It's possible that the crime interrupt handler is called without
pending interrupts (probably a hardware issue). To avoid irritating
"unexpected irq 71" messages, we now just ignore the spurious crime
interrupts.
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The non-NUMA case of build_zonelist_cache() would initialize the
zlcache_ptr for both node_zonelists[] to NULL.
Which is problematic, since non-NUMA only has a single node_zonelists[]
entry, and trying to zero the non-existent second one just overwrote the
nr_zones field instead.
As kswapd uses this value to determine what reclaim work is necessary,
the result is that kswapd never reclaims. This causes processes to
stall frequently in low-memory situations as they always direct reclaim.
This patch initialises zlcache_ptr correctly.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Tested-by: Dan Williams <dan.j.williams@intel.com>
[ Simplified patch a bit ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The 192 byte cache is not necessary if we have a basic alignment of 128
byte. If it would be used then the 192 would be aligned to the next 128 byte
boundary which would result in another 256 byte cache. Two 256 kmalloc caches
cause sysfs to complain about a duplicate entry.
MIPS needs 128 byte aligned kmalloc caches and spits out warnings on boot without
this patch.
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
The legacy protocol's open operation doesn't handle an append operation
(it is expected that the client take care of it). We were incorrectly
passing the extended protocol's flag through even in legacy mode. This
was reported in bugzilla report #10689. This patch fixes the problem
by disallowing extended protocol open modes from being passed in legacy
mode and implemented append functionality on the client side by adding
a seek after the open.
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
fix this warning:
arch/x86/mm/init_64.c: In function 'early_memtest':
arch/x86/mm/init_64.c:524: warning: passing argument 2 of 'find_e820_area_size' from incompatible pointer type
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Fedora reports that mem_init()'s zap_low_mappings(), extended to SMP in
61165d7a03 x86: fix app crashes after SMP
resume causes 32-bit Intel Mac machines to reboot very early when
booting with EFI.
The EFI code appears to manage low mappings for itself when needed; but
like many before it, confuses PSE with PAE. So it has only been mapping
half the space it needed when PSE but not PAE. This remained unnoticed
until we moved the SMP zap_low_mappings() before
efi_enter_virtual_mode(). Presumably could have been noticed years ago
if anyone ran a UP kernel on such machines?
Reported-by: Peter Jones <pjones@redhat.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Peter Jones <pjones@redhat.com>
Cc: Glauber Costa <gcosta@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Tested-by: Peter Jones <pjones@redhat.com>
* 'i2c-fix' of git://aeryn.fluff.org.uk/bjdooks/linux:
I2C: S3C2410: Add MODULE_ALIAS() for s3c2440 device.
I2C: S3C2410: Fixup error codes returned rom a transfer.
I2C: S3C2410: Check ACK on byte transmission
* 'for-2.6.26' of git://git.kernel.dk/linux-2.6-block:
Properly notify block layer of sync writes
block: Fix the starving writes bug in the anticipatory IO scheduler
* git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/v4l-dvb:
V4L/DVB (8178): uvc: Fix compilation breakage for the other drivers, if uvc is selected
V4L/DVB (8145a): USB Video Class driver
* master.kernel.org:/home/rmk/linux-2.6-arm:
[ARM] 5131/1: Annotate platform_secondary_init with trace_hardirqs_off
[ARM] 5117/1: pxafb: fix __devinit/exit annotations
[ARM] Export dma_sync_sg_for_device()
[ARM] 5109/1: Mark rtc sa1100 driver as wakeup source before registering it
[ARM] 5116/1: pxafb: cleanup and fix order of failure handling
[ARM] 5115/1: pxafb: fix ifdef for command line option handling
ARM: OMAP: Correcting the gpmc prefetch control register address
ARM: OMAP: DMA: Don't mark channel active in omap_enable_channel_irq
Not sure how this came to get inverted but it appears to have been my
mess up.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
sched: fix divide error when trying to configure rt_period to zero
* 'i2c-for-linus' of git://jdelvare.pck.nerim.net/jdelvare-2.6:
i2c: Fix bad hint about irqs in i2c.h
i2c: Documentation: fix device matching description
* 'for-2.6.26' of git://neil.brown.name/md:
Fix error paths if md_probe fails.
Don't acknowlege that stripe-expand is complete until it really is.
Ensure interrupted recovery completed properly (v1 metadata plus bitmap)
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc:
powerpc/mpc5200: Fix lite5200b suspend/resume
powerpc/legacy_serial: Bail if reg-offset/shift properties are present
powerpc/bootwrapper: update for initrd with simpleImage
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (55 commits)
net: fib_rules: fix error code for unsupported families
netdevice: Fix wrong string handle in kernel command line parsing
net: Tyop of sk_filter() comment
netlink: Unneeded local variable
net-sched: fix filter destruction in atm/hfsc qdisc destruction
net-sched: change tcf_destroy_chain() to clear start of filter list
ipv4: fix sysctl documentation of time related values
mac80211: don't accept WEP keys other than WEP40 and WEP104
hostap: fix sparse warnings
hostap: don't report useless WDS frames by default
textsearch: fix Boyer-Moore text search bug
netfilter: nf_conntrack_tcp: fixing to check the lower bound of valid ACK
ipv6 route: Convert rt6_device_match() to use RT6_LOOKUP_F_xxx flags.
netlabel: Fix a problem when dumping the default IPv6 static labels
net/inet_lro: remove setting skb->ip_summed when not LRO-able
inet fragments: fix race between inet_frag_find and inet_frag_secret_rebuild
CONNECTOR: add a proc entry to list connectors
netlink: Fix some doc comments in net/netlink/attr.c
tcp: /proc/net/tcp rto,ato values not scaled properly (v2)
include/linux/netdevice.h: don't export MAX_HEADER to userspace
...
When scheduled swaps occur, we need to blit between front & back
buffers. If the buffers are tiled, we need to set the appropriate
XY_SRC_COPY tile bit, but only on 965 chips, since it will cause
corruption on pre-965 (e.g. 945).
Bug reported by and fix tested by Tomas Janousek <tomi@nomi.cz>.
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Acked-by: Dave Airlie <airlied@linux.ie>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 656acd2bbc ("Input: fix locking in
force-feedback core") causes the following regression on m68k:
| linux/drivers/input/ff-core.c: In function 'input_ff_upload':
| linux/drivers/input/ff-core.c:172: error: dereferencing pointer to incomplete type
| linux/drivers/input/ff-core.c: In function 'erase_effect':
| linux/drivers/input/ff-core.c:197: error: dereferencing pointer to incomplete type
| linux/drivers/input/ff-core.c:204: error: dereferencing pointer to incomplete type
| make[4]: *** [drivers/input/ff-core.o] Error 1
As the incomplete type is `struct task_struct', including <linux/sched.h> fixes
it.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
During the development of the physical PCI slot patch series, Gary Hade
kept on reporting strange oopses due to interactions between pci_slot
and acpiphp.
http://lkml.org/lkml/2007/11/28/319
find_root_bridges() unconditionally installs
handle_hotplug_event_bridge() as an ACPI_SYSTEM_NOTIFY handler for all
root bridges.
However, during module cleanup, remove_bridge() will only remove the
notify handler iff the root bridge had a hot-pluggable slot directly
underneath. That is:
root bridge -> hotplug slot
But, if the topology looks like either of the following:
root bridge -> non-hotplug slot
root bridge -> p2p bridge -> hotplug slot
Then we currently do not remove the notify handler from that root
bridge.
This can cause a kernel oops if we modprobe acpiphp later and it gets
loaded somewhere else in memory. If the root bridge then receives a
hotplug event, it will then attempt to call a stale, non-existent notify
handler and we blow up.
Much thanks goes to Gary Hade for his persistent debugging efforts.
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Gary Hade <garyhade@us.ibm.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
For Broadcom 5706, 5708, 5709 rev. A nics, any read beyond the
VPD end tag will hang the device. This problem was initially
observed when a vpd entry was created in sysfs
('/sys/bus/pci/devices/<id>/vpd'). A read to this sysfs entry
will dump 32k of data. Reading a full 32k will cause an access
beyond the VPD end tag causing the device to hang. Once the device
is hung, the bnx2 driver will not be able to reset the device.
We believe that it is legal to read beyond the end tag and
therefore the solution is to limit the read/write length.
A majority of this patch is from Matthew Wilcox who gave code for
reworking the PCI vpd size information. A PCI quirk added for the
Broadcom NIC's to limit the read/write's.
Signed-off-by: Benjamin Li <benli@broadcom.com>
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
UVC makefile defines obj as:
obj-$(CONFIG_USB_VIDEO_CLASS) := uvcvideo.o
Instead of:
obj-$(CONFIG_USB_VIDEO_CLASS) += uvcvideo.o
Due to that, if uvc is selected, all obj-y or obj-m that were added to
compilation were forget. This breaks a proper kernel build.
Acked-by: Laurent Pinchart <laurent.pinchart@skynet.be>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
Add cond_resched() to prevent monopolising CPU when processing large bios.
dm-crypt processes encryption of bios in sector units. If the bio request
is big it can spend a long time in the encryption call.
Signed-off-by: Milan Broz <mbroz@redhat.com>
Tested-by: Yan Li <elliot.li.tech@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
The errno code returned must be negative.
Fixes "RTNETLINK answers: Unknown error 18446744073709551519".
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
v1->v2: Use strlcpy() to ensure s[i].name be null-termination.
1. In netdev_boot_setup_add(), a long name will leak.
ex. : dev=21,0x1234,0x1234,0x2345,eth123456789verylongname.........
2. In netdev_boot_setup_check(), mismatch will happen if s[i].name
is a substring of dev->name.
ex. : dev=...eth1 dev=...eth11
[ With feedback from Ben Hutchings. ]
Signed-off-by: Wang Chen <wangchen@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We already have a variable, which has the same capability.
Signed-off-by: Wang Chen <wangchen@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Filters need to be destroyed before beginning to destroy classes
since the destination class needs to still be alive to unbind the
filter.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pass double tcf_proto pointers to tcf_destroy_chain() to make it
clear the start of the filter list for more consistency.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
These sysctl values are time related and all use the same routine
(proc_dointvec_jiffies) that internally converts from seconds to jiffies.
The code is fine, the documentation is just wrong.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Suspend/resume ("echo mem > /sys/power/state") does not work with
vanilla kernels -- the system does not suspend correctly and just
hangs. This patch fixes this so suspend/resume works:
1) of_iomap does not map the whole 0xC000 of the MPC5200 immr so
saving registers does not work.
2) PCI registers need to be saved and restored.
Signed-off-by: Tim Yamin <plasm@roo.me.uk>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
The legacy serial driver does not work with an 8250 type UART that is
described in the device tree with the reg-offset and reg-shift
properties. This change makes legacy_serial ignore these devices.
Signed-off-by: John Linn <john.linn@xilinx.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
i2c.h mentions -1 as a not-issued irq. This false hint was taken by
of_i2c and caused crashes. Don't give any advice as 'no irq' is not
consistent across all architectures yet and it is not needed internally
by the i2c-core.
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The matching process described for new style clients in
Documentation/i2c/writing-clients is classed as out-of-date
as it requires the presence of an .id_table entry in the
driver's i2c_driver entry.
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
This change to the makefile corrects the build of a simpleImage with initrd.
Signed-off-by: John Linn <john.linn@xilinx>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Some PCI devices will lock up if we attempt to read from VPD addresses
beyond some device-dependent limit. Until we can identify these
devices and adjust the file size accordingly, only let root read VPD
through sysfs to prevent a DoS by normal users.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Add a MODULE_ALIAS() statement for the i2c-s3c2410 controller
to ensure that it can be autoloaded on the S3C2440 systems that
we support.
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
The driver should be returning -ENXIO for transfers that do not
pass the initial address byte stage.
Note, also small tidyups to the driver comments in the area.
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
We should check for the reception of an ACK after transmitting each
data byte. The address send has been correctly checking this, but the
data write byte state should have also been checking for these failures.
As part of the same fix, we remove the ACK checking from the receive
path where it should not have been checking for an ACK which our hardware
was sending.
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Dhaval Giani reported this warning during cpu hotplug stress-tests:
| On running kernel compiles in parallel with cpu hotplug:
|
| WARNING: at arch/x86/kernel/smp.c:118
| native_smp_send_reschedule+0x21/0x36()
| Modules linked in:
| Pid: 27483, comm: cc1 Not tainted 2.6.26-rc7 #1
| [...]
| [<c0110355>] native_smp_send_reschedule+0x21/0x36
| [<c014fe8f>] force_quiescent_state+0x47/0x57
| [<c014fef0>] call_rcu+0x51/0x6d
| [<c01713b3>] __fput+0x130/0x158
| [<c0171231>] fput+0x17/0x19
| [<c016fd99>] filp_close+0x4d/0x57
| [<c016fdff>] sys_close+0x5c/0x97
IMHO the warning is a spurious one.
cpu_online_map is updated by the _cpu_down() using stop_machine_run().
Since force_quiescent_state is invoked from irqs disabled section,
stop_machine_run() won't be executing while a cpu is executing
force_quiescent_state(). Hence the cpu_online_map is stable while we're
in the irq disabled section.
However, a cpu might have been offlined _just_ before we disabled irqs
while entering force_quiescent_state(). And rcu subsystem might not yet
have handled the CPU_DEAD notification, leading to the offlined cpu's
bit being set in the rcp->cpumask.
Hence cpumask = (rcp->cpumask & cpu_online_map) to prevent sending
smp_reschedule() to an offlined CPU.
Here's the timeline:
CPU_A CPU_B
--------------------------------------------------------------
cpu_down(): .
. .
. .
stop_machine(): /* disables preemption, .
* and irqs */ .
. .
. .
take_cpu_down(); .
. .
. .
. .
cpu_disable(); /*this removes cpu .
*from cpu_online_map .
*/ .
. .
. .
restart_machine(); /* enables irqs */ .
------WINDOW DURING WHICH rcp->cpumask is stale ---------------
. call_rcu();
. /* disables irqs here */
. .force_quiescent_state();
.CPU_DEAD: .for_each_cpu(rcp->cpumask)
. . smp_send_reschedule();
. .
. . WARN_ON() for offlined CPU!
.
.
.
rcu_cpu_notify:
.
-------- WINDOW ENDS ------------------------------------------
rcu_offline_cpu() /* Which calls cpu_quiet()
* which removes
* cpu from rcp->cpumask.
*/
If a new batch was started just before calling stop_machine_run(), the
"tobe-offlined" cpu is still present in rcp-cpumask.
During a cpu-offline, from take_cpu_down(), we queue an rt-prio idle
task as the next task to be picked by the scheduler. We also call
cpu_disable() which will disable any further interrupts and remove the
cpu's bit from the cpu_online_map.
Once the stop_machine_run() successfully calls take_cpu_down(), it calls
schedule(). That's the last time a schedule is called on the offlined
cpu, and hence the last time when rdp->passed_quiesc will be set to 1
through rcu_qsctr_inc().
But the cpu_quiet() will be on this cpu will be called only when the
next RCU_SOFTIRQ occurs on this CPU. So at this time, the offlined CPU
is still set in rcp->cpumask.
Now coming back to the idle_task which truely offlines the CPU, it does
check for a pending RCU and raises the softirq, since it will find
rdp->passed_quiesc to be 0 in this case. However, since the cpu is
offline I am not sure if the softirq will trigger on the CPU.
Even if it doesn't the rcu_offline_cpu() will find that rcp->completed
is not the same as rcp->cur, which means that our cpu could be holding
up the grace period progression. Hence we call cpu_quiet() and move
ahead.
But because of the window explained in the timeline, we could still have
a call_rcu() before the RCU subsystem executes it's CPU_DEAD
notification, and we send smp_send_reschedule() to offlined cpu while
trying to force the quiescent states. The appended patch adds comments
and prevents checking for offlined cpu everytime.
cpu_online_map is updated by the _cpu_down() using stop_machine_run().
Since force_quiescent_state is invoked from irqs disabled section,
stop_machine_run() won't be executing while a cpu is executing
force_quiescent_state(). Hence the cpu_online_map is stable while we're
in the irq disabled section.
Reported-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Acked-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Rusty Russel <rusty@rustcorp.com.au>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
fsync_buffers_list() and sync_dirty_buffer() both issue async writes and
then immediately wait on them. Conceptually, that makes them sync writes
and we should treat them as such so that the IO schedulers can handle
them appropriately.
This patch fixes a write starvation issue that Lin Ming reported, where
xx is stuck for more than 2 minutes because of a large number of
synchronous IO in the system:
INFO: task kjournald:20558 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this
message.
kjournald D ffff810010820978 6712 20558 2
ffff81022ddb1d10 0000000000000046 ffff81022e7baa10 ffffffff803ba6f2
ffff81022ecd0000 ffff8101e6dc9160 ffff81022ecd0348 000000008048b6cb
0000000000000086 ffff81022c4e8d30 0000000000000000 ffffffff80247537
Call Trace:
[<ffffffff803ba6f2>] kobject_get+0x12/0x17
[<ffffffff80247537>] getnstimeofday+0x2f/0x83
[<ffffffff8029c1ac>] sync_buffer+0x0/0x3f
[<ffffffff8066d195>] io_schedule+0x5d/0x9f
[<ffffffff8029c1e7>] sync_buffer+0x3b/0x3f
[<ffffffff8066d3f0>] __wait_on_bit+0x40/0x6f
[<ffffffff8029c1ac>] sync_buffer+0x0/0x3f
[<ffffffff8066d48b>] out_of_line_wait_on_bit+0x6c/0x78
[<ffffffff80243909>] wake_bit_function+0x0/0x23
[<ffffffff8029e3ad>] sync_dirty_buffer+0x98/0xcb
[<ffffffff8030056b>] journal_commit_transaction+0x97d/0xcb6
[<ffffffff8023a676>] lock_timer_base+0x26/0x4b
[<ffffffff8030300a>] kjournald+0xc1/0x1fb
[<ffffffff802438db>] autoremove_wake_function+0x0/0x2e
[<ffffffff80302f49>] kjournald+0x0/0x1fb
[<ffffffff802437bb>] kthread+0x47/0x74
[<ffffffff8022de51>] schedule_tail+0x28/0x5d
[<ffffffff8020cac8>] child_rip+0xa/0x12
[<ffffffff80243774>] kthread+0x0/0x74
[<ffffffff8020cabe>] child_rip+0x0/0x12
Lin Ming confirms that this patch fixes the issue. I've run tests with
it for the past week and no ill effects have been observed, so I'm
proposing it for inclusion into 2.6.26.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
AS scheduler alternates between issuing read and write batches. It does
the batch switch only after all requests from the previous batch are
completed.
When switching to a write batch, if there is an on-going read request,
it waits for its completion and indicates its intention of switching by
setting ad->changed_batch and the new direction but does not update the
batch_expire_time for the new write batch which it does in the case of
no previous pending requests.
On completion of the read request, it sees that we were waiting for the
switch and schedules work for kblockd right away and resets the
ad->changed_data flag.
Now when kblockd enters dispatch_request where it is expected to pick
up a write request, it in turn ends the write batch because the
batch_expire_timer was not updated and shows the expire timestamp for
the previous batch.
This results in the write starvation for all the cases where there is
the intention for switching to a write batch, but there is a previous
in-flight read request and the batch gets reverted to a read_batch
right away.
This also holds true in the reverse case (switching from a write batch
to a read batch with an in-flight write request).
I've checked that this bug exists on 2.6.11, 2.6.18, 2.6.24 and
linux-2.6-block git HEAD. I've tested the fix on x86 platforms with
SCSI drives where the driver asks for the next request while a current
request is in-flight.
This patch is based off linux-2.6-block git HEAD.
Bug reproduction:
A simple scenario which reproduces this bug is:
- dd if=/dev/hda3 of=/dev/null &
- lilo
The lilo takes forever to complete.
This can also be reproduced fairly easily with the earlier dd and
another test
program doing msync().
The example test program below should print out a message after every
iteration
but it simply hangs forever. With this bugfix it makes forward progress.
====
Example test program using msync() (thanks to suleiman AT google DOT
com)
inline uint64_t
rdtsc(void)
{
int64_t tsc;
__asm __volatile("rdtsc" : "=A" (tsc));
return (tsc);
}
int
main(int argc, char **argv)
{
struct stat st;
uint64_t e, s, t;
char *p, q;
long i;
int fd;
if (argc < 2) {
printf("Usage: %s <file>\n", argv[0]);
return (1);
}
if ((fd = open(argv[1], O_RDWR | O_NOATIME)) < 0)
err(1, "open");
if (fstat(fd, &st) < 0)
err(1, "fstat");
p = mmap(NULL, st.st_size, PROT_READ | PROT_WRITE,
MAP_SHARED, fd, 0);
t = 0;
for (i = 0; i < 1000; i++) {
*p = 0;
msync(p, 4096, MS_SYNC);
s = rdtsc();
*p = 0;
__asm __volatile(""::: "memory");
e = rdtsc();
if (argc > 2)
printf("%d: %lld cycles %jd %jd\n",
i, e - s, (intmax_t)s, (intmax_t)e);
t += e - s;
}
printf("average time: %lld cycles\n", t / 1000);
return (0);
}
Cc: <stable@kernel.org>
Acked-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
