linux/net/core/dst.c

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/*
* net/core/dst.c Protocol independent destination cache.
*
* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
*
*/
#include <linux/bitops.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kernel.h>
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
#include <linux/workqueue.h>
#include <linux/mm.h>
#include <linux/module.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#include <linux/slab.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/string.h>
#include <linux/types.h>
#include <net/net_namespace.h>
#include <linux/sched.h>
#include <linux/prefetch.h>
#include <net/lwtunnel.h>
#include <net/dst.h>
#include <net/dst_metadata.h>
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
/*
* Theory of operations:
* 1) We use a list, protected by a spinlock, to add
* new entries from both BH and non-BH context.
* 2) In order to keep spinlock held for a small delay,
* we use a second list where are stored long lived
* entries, that are handled by the garbage collect thread
* fired by a workqueue.
* 3) This list is guarded by a mutex,
* so that the gc_task and dst_dev_event() can be synchronized.
*/
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
/*
* We want to keep lock & list close together
* to dirty as few cache lines as possible in __dst_free().
* As this is not a very strong hint, we dont force an alignment on SMP.
*/
static struct {
spinlock_t lock;
struct dst_entry *list;
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
unsigned long timer_inc;
unsigned long timer_expires;
} dst_garbage = {
.lock = __SPIN_LOCK_UNLOCKED(dst_garbage.lock),
.timer_inc = DST_GC_MAX,
};
static void dst_gc_task(struct work_struct *work);
static void ___dst_free(struct dst_entry *dst);
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
static DECLARE_DELAYED_WORK(dst_gc_work, dst_gc_task);
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
static DEFINE_MUTEX(dst_gc_mutex);
/*
* long lived entries are maintained in this list, guarded by dst_gc_mutex
*/
static struct dst_entry *dst_busy_list;
static void dst_gc_task(struct work_struct *work)
{
int delayed = 0;
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
int work_performed = 0;
unsigned long expires = ~0L;
struct dst_entry *dst, *next, head;
struct dst_entry *last = &head;
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
mutex_lock(&dst_gc_mutex);
next = dst_busy_list;
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
loop:
while ((dst = next) != NULL) {
next = dst->next;
prefetch(&next->next);
cond_resched();
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
if (likely(atomic_read(&dst->__refcnt))) {
last->next = dst;
last = dst;
delayed++;
continue;
}
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
work_performed++;
dst = dst_destroy(dst);
if (dst) {
/* NOHASH and still referenced. Unless it is already
* on gc list, invalidate it and add to gc list.
*
* Note: this is temporary. Actually, NOHASH dst's
* must be obsoleted when parent is obsoleted.
* But we do not have state "obsoleted, but
* referenced by parent", so it is right.
*/
if (dst->obsolete > 0)
continue;
___dst_free(dst);
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
dst->next = next;
next = dst;
}
}
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
spin_lock_bh(&dst_garbage.lock);
next = dst_garbage.list;
if (next) {
dst_garbage.list = NULL;
spin_unlock_bh(&dst_garbage.lock);
goto loop;
}
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
last->next = NULL;
dst_busy_list = head.next;
if (!dst_busy_list)
dst_garbage.timer_inc = DST_GC_MAX;
else {
/*
* if we freed less than 1/10 of delayed entries,
* we can sleep longer.
*/
if (work_performed <= delayed/10) {
dst_garbage.timer_expires += dst_garbage.timer_inc;
if (dst_garbage.timer_expires > DST_GC_MAX)
dst_garbage.timer_expires = DST_GC_MAX;
dst_garbage.timer_inc += DST_GC_INC;
} else {
dst_garbage.timer_inc = DST_GC_INC;
dst_garbage.timer_expires = DST_GC_MIN;
}
expires = dst_garbage.timer_expires;
/*
* if the next desired timer is more than 4 seconds in the
* future then round the timer to whole seconds
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
*/
if (expires > 4*HZ)
expires = round_jiffies_relative(expires);
schedule_delayed_work(&dst_gc_work, expires);
}
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
spin_unlock_bh(&dst_garbage.lock);
mutex_unlock(&dst_gc_mutex);
}
int dst_discard_sk(struct sock *sk, struct sk_buff *skb)
{
kfree_skb(skb);
return 0;
}
EXPORT_SYMBOL(dst_discard_sk);
const u32 dst_default_metrics[RTAX_MAX + 1] = {
/* This initializer is needed to force linker to place this variable
* into const section. Otherwise it might end into bss section.
* We really want to avoid false sharing on this variable, and catch
* any writes on it.
*/
[RTAX_MAX] = 0xdeadbeef,
};
void dst_init(struct dst_entry *dst, struct dst_ops *ops,
struct net_device *dev, int initial_ref, int initial_obsolete,
unsigned short flags)
{
dst->child = NULL;
dst->dev = dev;
if (dev)
dev_hold(dev);
dst->ops = ops;
net: Implement read-only protection and COW'ing of metrics. Routing metrics are now copy-on-write. Initially a route entry points it's metrics at a read-only location. If a routing table entry exists, it will point there. Else it will point at the all zero metric place-holder called 'dst_default_metrics'. The writeability state of the metrics is stored in the low bits of the metrics pointer, we have two bits left to spare if we want to store more states. For the initial implementation, COW is implemented simply via kmalloc. However future enhancements will change this to place the writable metrics somewhere else, in order to increase sharing. Very likely this "somewhere else" will be the inetpeer cache. Note also that this means that metrics updates may transiently fail if we cannot COW the metrics successfully. But even by itself, this patch should decrease memory usage and increase cache locality especially for routing workloads. In those cases the read-only metric copies stay in place and never get written to. TCP workloads where metrics get updated, and those rare cases where PMTU triggers occur, will take a very slight performance hit. But that hit will be alleviated when the long-term writable metrics move to a more sharable location. Since the metrics storage went from a u32 array of RTAX_MAX entries to what is essentially a pointer, some retooling of the dst_entry layout was necessary. Most importantly, we need to preserve the alignment of the reference count so that it doesn't share cache lines with the read-mostly state, as per Eric Dumazet's alignment assertion checks. The only non-trivial bit here is the move of the 'flags' member into the writeable cacheline. This is OK since we are always accessing the flags around the same moment when we made a modification to the reference count. Signed-off-by: David S. Miller <davem@davemloft.net>
2011-01-27 04:51:05 +00:00
dst_init_metrics(dst, dst_default_metrics, true);
dst->expires = 0UL;
dst->path = dst;
ipv6: fix race condition regarding dst->expires and dst->from. Eric Dumazet wrote: | Some strange crashes happen in rt6_check_expired(), with access | to random addresses. | | At first glance, it looks like the RTF_EXPIRES and | stuff added in commit 1716a96101c49186b | (ipv6: fix problem with expired dst cache) | are racy : same dst could be manipulated at the same time | on different cpus. | | At some point, our stack believes rt->dst.from contains a dst pointer, | while its really a jiffie value (as rt->dst.expires shares the same area | of memory) | | rt6_update_expires() should be fixed, or am I missing something ? | | CC Neil because of https://bugzilla.redhat.com/show_bug.cgi?id=892060 Because we do not have any locks for dst_entry, we cannot change essential structure in the entry; e.g., we cannot change reference to other entity. To fix this issue, split 'from' and 'expires' field in dst_entry out of union. Once it is 'from' is assigned in the constructor, keep the reference until the very last stage of the life time of the object. Of course, it is unsafe to change 'from', so make rt6_set_from simple just for fresh entries. Reported-by: Eric Dumazet <eric.dumazet@gmail.com> Reported-by: Neil Horman <nhorman@tuxdriver.com> CC: Gao Feng <gaofeng@cn.fujitsu.com> Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Reported-by: Steinar H. Gunderson <sesse@google.com> Reviewed-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-02-20 00:29:08 +00:00
dst->from = NULL;
#ifdef CONFIG_XFRM
dst->xfrm = NULL;
#endif
dst->input = dst_discard;
dst->output = dst_discard_sk;
dst->error = 0;
dst->obsolete = initial_obsolete;
dst->header_len = 0;
dst->trailer_len = 0;
#ifdef CONFIG_IP_ROUTE_CLASSID
dst->tclassid = 0;
#endif
dst->lwtstate = NULL;
atomic_set(&dst->__refcnt, initial_ref);
dst->__use = 0;
dst->lastuse = jiffies;
dst->flags = flags;
dst->pending_confirm = 0;
dst->next = NULL;
if (!(flags & DST_NOCOUNT))
dst_entries_add(ops, 1);
}
EXPORT_SYMBOL(dst_init);
void *dst_alloc(struct dst_ops *ops, struct net_device *dev,
int initial_ref, int initial_obsolete, unsigned short flags)
{
struct dst_entry *dst;
if (ops->gc && dst_entries_get_fast(ops) > ops->gc_thresh) {
if (ops->gc(ops))
return NULL;
}
dst = kmem_cache_alloc(ops->kmem_cachep, GFP_ATOMIC);
if (!dst)
return NULL;
dst_init(dst, ops, dev, initial_ref, initial_obsolete, flags);
return dst;
}
EXPORT_SYMBOL(dst_alloc);
static void ___dst_free(struct dst_entry *dst)
{
/* The first case (dev==NULL) is required, when
protocol module is unloaded.
*/
if (dst->dev == NULL || !(dst->dev->flags&IFF_UP)) {
dst->input = dst_discard;
dst->output = dst_discard_sk;
}
dst->obsolete = DST_OBSOLETE_DEAD;
}
void __dst_free(struct dst_entry *dst)
{
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
spin_lock_bh(&dst_garbage.lock);
___dst_free(dst);
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
dst->next = dst_garbage.list;
dst_garbage.list = dst;
if (dst_garbage.timer_inc > DST_GC_INC) {
dst_garbage.timer_inc = DST_GC_INC;
dst_garbage.timer_expires = DST_GC_MIN;
workqueue: use mod_delayed_work() instead of cancel + queue Convert delayed_work users doing cancel_delayed_work() followed by queue_delayed_work() to mod_delayed_work(). Most conversions are straight-forward. Ones worth mentioning are, * drivers/edac/edac_mc.c: edac_mc_workq_setup() converted to always use mod_delayed_work() and cancel loop in edac_mc_reset_delay_period() is dropped. * drivers/platform/x86/thinkpad_acpi.c: No need to remember whether watchdog is active or not. @fan_watchdog_active and related code dropped. * drivers/power/charger-manager.c: Seemingly a lot of delayed_work_pending() abuse going on here. [delayed_]work_pending() are unsynchronized and racy when used like this. I converted one instance in fullbatt_handler(). Please conver the rest so that it invokes workqueue APIs for the intended target state rather than trying to game work item pending state transitions. e.g. if timer should be modified - call mod_delayed_work(), canceled - call cancel_delayed_work[_sync](). * drivers/thermal/thermal_sys.c: thermal_zone_device_set_polling() simplified. Note that round_jiffies() calls in this function are meaningless. round_jiffies() work on absolute jiffies not delta delay used by delayed_work. v2: Tomi pointed out that __cancel_delayed_work() users can't be safely converted to mod_delayed_work(). They could be calling it from irq context and if that happens while delayed_work_timer_fn() is running, it could deadlock. __cancel_delayed_work() users are dropped. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Acked-by: Anton Vorontsov <cbouatmailru@gmail.com> Acked-by: David Howells <dhowells@redhat.com> Cc: Tomi Valkeinen <tomi.valkeinen@ti.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Doug Thompson <dougthompson@xmission.com> Cc: David Airlie <airlied@linux.ie> Cc: Roland Dreier <roland@kernel.org> Cc: "John W. Linville" <linville@tuxdriver.com> Cc: Zhang Rui <rui.zhang@intel.com> Cc: Len Brown <len.brown@intel.com> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Johannes Berg <johannes@sipsolutions.net>
2012-08-03 17:30:47 +00:00
mod_delayed_work(system_wq, &dst_gc_work,
dst_garbage.timer_expires);
}
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
spin_unlock_bh(&dst_garbage.lock);
}
EXPORT_SYMBOL(__dst_free);
struct dst_entry *dst_destroy(struct dst_entry * dst)
{
struct dst_entry *child;
smp_rmb();
again:
child = dst->child;
if (!(dst->flags & DST_NOCOUNT))
dst_entries_add(dst->ops, -1);
if (dst->ops->destroy)
dst->ops->destroy(dst);
if (dst->dev)
dev_put(dst->dev);
if (dst->flags & DST_METADATA)
kfree(dst);
else
kmem_cache_free(dst->ops->kmem_cachep, dst);
lwtstate_put(dst->lwtstate);
dst = child;
if (dst) {
int nohash = dst->flags & DST_NOHASH;
if (atomic_dec_and_test(&dst->__refcnt)) {
/* We were real parent of this dst, so kill child. */
if (nohash)
goto again;
} else {
/* Child is still referenced, return it for freeing. */
if (nohash)
return dst;
/* Child is still in his hash table */
}
}
return NULL;
}
EXPORT_SYMBOL(dst_destroy);
static void dst_destroy_rcu(struct rcu_head *head)
{
struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
dst = dst_destroy(dst);
if (dst)
__dst_free(dst);
}
void dst_release(struct dst_entry *dst)
{
if (dst) {
int newrefcnt;
net: speedup dst_release() During tbench/oprofile sessions, I found that dst_release() was in third position. CPU: Core 2, speed 2999.68 MHz (estimated) Counted CPU_CLK_UNHALTED events (Clock cycles when not halted) with a unit mask of 0x00 (Unhalted core cycles) count 100000 samples % symbol name 483726 9.0185 __copy_user_zeroing_intel 191466 3.5697 __copy_user_intel 185475 3.4580 dst_release 175114 3.2648 ip_queue_xmit 153447 2.8608 tcp_sendmsg 108775 2.0280 tcp_recvmsg 102659 1.9140 sysenter_past_esp 101450 1.8914 tcp_current_mss 95067 1.7724 __copy_from_user_ll 86531 1.6133 tcp_transmit_skb Of course, all CPUS fight on the dst_entry associated with 127.0.0.1 Instead of first checking the refcount value, then decrement it, we use atomic_dec_return() to help CPU to make the right memory transaction (ie getting the cache line in exclusive mode) dst_release() is now at the fifth position, and tbench a litle bit faster ;) CPU: Core 2, speed 3000.1 MHz (estimated) Counted CPU_CLK_UNHALTED events (Clock cycles when not halted) with a unit mask of 0x00 (Unhalted core cycles) count 100000 samples % symbol name 647107 8.8072 __copy_user_zeroing_intel 258840 3.5229 ip_queue_xmit 258302 3.5155 __copy_user_intel 209629 2.8531 tcp_sendmsg 165632 2.2543 dst_release 149232 2.0311 tcp_current_mss 147821 2.0119 tcp_recvmsg 137893 1.8767 sysenter_past_esp 127473 1.7349 __copy_from_user_ll 121308 1.6510 ip_finish_output 118510 1.6129 tcp_transmit_skb 109295 1.4875 tcp_v4_rcv Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-14 08:53:54 +00:00
newrefcnt = atomic_dec_return(&dst->__refcnt);
if (unlikely(newrefcnt < 0))
net_warn_ratelimited("%s: dst:%p refcnt:%d\n",
__func__, dst, newrefcnt);
if (unlikely(dst->flags & DST_NOCACHE) && !newrefcnt)
call_rcu(&dst->rcu_head, dst_destroy_rcu);
}
}
EXPORT_SYMBOL(dst_release);
net: Implement read-only protection and COW'ing of metrics. Routing metrics are now copy-on-write. Initially a route entry points it's metrics at a read-only location. If a routing table entry exists, it will point there. Else it will point at the all zero metric place-holder called 'dst_default_metrics'. The writeability state of the metrics is stored in the low bits of the metrics pointer, we have two bits left to spare if we want to store more states. For the initial implementation, COW is implemented simply via kmalloc. However future enhancements will change this to place the writable metrics somewhere else, in order to increase sharing. Very likely this "somewhere else" will be the inetpeer cache. Note also that this means that metrics updates may transiently fail if we cannot COW the metrics successfully. But even by itself, this patch should decrease memory usage and increase cache locality especially for routing workloads. In those cases the read-only metric copies stay in place and never get written to. TCP workloads where metrics get updated, and those rare cases where PMTU triggers occur, will take a very slight performance hit. But that hit will be alleviated when the long-term writable metrics move to a more sharable location. Since the metrics storage went from a u32 array of RTAX_MAX entries to what is essentially a pointer, some retooling of the dst_entry layout was necessary. Most importantly, we need to preserve the alignment of the reference count so that it doesn't share cache lines with the read-mostly state, as per Eric Dumazet's alignment assertion checks. The only non-trivial bit here is the move of the 'flags' member into the writeable cacheline. This is OK since we are always accessing the flags around the same moment when we made a modification to the reference count. Signed-off-by: David S. Miller <davem@davemloft.net>
2011-01-27 04:51:05 +00:00
u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old)
{
u32 *p = kmalloc(sizeof(u32) * RTAX_MAX, GFP_ATOMIC);
if (p) {
u32 *old_p = __DST_METRICS_PTR(old);
unsigned long prev, new;
memcpy(p, old_p, sizeof(u32) * RTAX_MAX);
new = (unsigned long) p;
prev = cmpxchg(&dst->_metrics, old, new);
if (prev != old) {
kfree(p);
p = __DST_METRICS_PTR(prev);
if (prev & DST_METRICS_READ_ONLY)
p = NULL;
}
}
return p;
}
EXPORT_SYMBOL(dst_cow_metrics_generic);
/* Caller asserts that dst_metrics_read_only(dst) is false. */
void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old)
{
unsigned long prev, new;
new = ((unsigned long) dst_default_metrics) | DST_METRICS_READ_ONLY;
net: Implement read-only protection and COW'ing of metrics. Routing metrics are now copy-on-write. Initially a route entry points it's metrics at a read-only location. If a routing table entry exists, it will point there. Else it will point at the all zero metric place-holder called 'dst_default_metrics'. The writeability state of the metrics is stored in the low bits of the metrics pointer, we have two bits left to spare if we want to store more states. For the initial implementation, COW is implemented simply via kmalloc. However future enhancements will change this to place the writable metrics somewhere else, in order to increase sharing. Very likely this "somewhere else" will be the inetpeer cache. Note also that this means that metrics updates may transiently fail if we cannot COW the metrics successfully. But even by itself, this patch should decrease memory usage and increase cache locality especially for routing workloads. In those cases the read-only metric copies stay in place and never get written to. TCP workloads where metrics get updated, and those rare cases where PMTU triggers occur, will take a very slight performance hit. But that hit will be alleviated when the long-term writable metrics move to a more sharable location. Since the metrics storage went from a u32 array of RTAX_MAX entries to what is essentially a pointer, some retooling of the dst_entry layout was necessary. Most importantly, we need to preserve the alignment of the reference count so that it doesn't share cache lines with the read-mostly state, as per Eric Dumazet's alignment assertion checks. The only non-trivial bit here is the move of the 'flags' member into the writeable cacheline. This is OK since we are always accessing the flags around the same moment when we made a modification to the reference count. Signed-off-by: David S. Miller <davem@davemloft.net>
2011-01-27 04:51:05 +00:00
prev = cmpxchg(&dst->_metrics, old, new);
if (prev == old)
kfree(__DST_METRICS_PTR(old));
}
EXPORT_SYMBOL(__dst_destroy_metrics_generic);
static struct dst_ops md_dst_ops = {
.family = AF_UNSPEC,
};
static int dst_md_discard_sk(struct sock *sk, struct sk_buff *skb)
{
WARN_ONCE(1, "Attempting to call output on metadata dst\n");
kfree_skb(skb);
return 0;
}
static int dst_md_discard(struct sk_buff *skb)
{
WARN_ONCE(1, "Attempting to call input on metadata dst\n");
kfree_skb(skb);
return 0;
}
static void __metadata_dst_init(struct metadata_dst *md_dst, u8 optslen)
{
struct dst_entry *dst;
dst = &md_dst->dst;
dst_init(dst, &md_dst_ops, NULL, 1, DST_OBSOLETE_NONE,
DST_METADATA | DST_NOCACHE | DST_NOCOUNT);
dst->input = dst_md_discard;
dst->output = dst_md_discard_sk;
memset(dst + 1, 0, sizeof(*md_dst) + optslen - sizeof(*dst));
md_dst->opts_len = optslen;
}
struct metadata_dst *metadata_dst_alloc(u8 optslen, gfp_t flags)
{
struct metadata_dst *md_dst;
md_dst = kmalloc(sizeof(*md_dst) + optslen, flags);
if (!md_dst)
return NULL;
__metadata_dst_init(md_dst, optslen);
return md_dst;
}
EXPORT_SYMBOL_GPL(metadata_dst_alloc);
struct metadata_dst __percpu *metadata_dst_alloc_percpu(u8 optslen, gfp_t flags)
{
int cpu;
struct metadata_dst __percpu *md_dst;
md_dst = __alloc_percpu_gfp(sizeof(struct metadata_dst) + optslen,
__alignof__(struct metadata_dst), flags);
if (!md_dst)
return NULL;
for_each_possible_cpu(cpu)
__metadata_dst_init(per_cpu_ptr(md_dst, cpu), optslen);
return md_dst;
}
EXPORT_SYMBOL_GPL(metadata_dst_alloc_percpu);
/* Dirty hack. We did it in 2.2 (in __dst_free),
* we have _very_ good reasons not to repeat
* this mistake in 2.3, but we have no choice
* now. _It_ _is_ _explicit_ _deliberate_
* _race_ _condition_.
*
* Commented and originally written by Alexey.
*/
static void dst_ifdown(struct dst_entry *dst, struct net_device *dev,
int unregister)
{
if (dst->ops->ifdown)
dst->ops->ifdown(dst, dev, unregister);
if (dev != dst->dev)
return;
if (!unregister) {
dst->input = dst_discard;
dst->output = dst_discard_sk;
} else {
dst->dev = dev_net(dst->dev)->loopback_dev;
dev_hold(dst->dev);
dev_put(dev);
}
}
static int dst_dev_event(struct notifier_block *this, unsigned long event,
void *ptr)
{
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
struct dst_entry *dst, *last = NULL;
switch (event) {
case NETDEV_UNREGISTER_FINAL:
case NETDEV_DOWN:
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
mutex_lock(&dst_gc_mutex);
for (dst = dst_busy_list; dst; dst = dst->next) {
last = dst;
dst_ifdown(dst, dev, event != NETDEV_DOWN);
}
spin_lock_bh(&dst_garbage.lock);
dst = dst_garbage.list;
dst_garbage.list = NULL;
spin_unlock_bh(&dst_garbage.lock);
if (last)
last->next = dst;
else
dst_busy_list = dst;
for (; dst; dst = dst->next)
dst_ifdown(dst, dev, event != NETDEV_DOWN);
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
mutex_unlock(&dst_gc_mutex);
break;
}
return NOTIFY_DONE;
}
static struct notifier_block dst_dev_notifier = {
.notifier_call = dst_dev_event,
.priority = -10, /* must be called after other network notifiers */
};
void __init dst_subsys_init(void)
{
register_netdevice_notifier(&dst_dev_notifier);
}