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sched/numa, mm: Remove p->numa_migrate_deferred

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Excessive migration of pages can hurt the performance of workloads
that span multiple NUMA nodes.  However, it turns out that the
p->numa_migrate_deferred knob is a really big hammer, which does
reduce migration rates, but does not actually help performance.

Now that the second stage of the automatic numa balancing code
has stabilized, it is time to replace the simplistic migration
deferral code with something smarter.

Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Chegu Vinod <chegu_vinod@hp.com>
Link: http://lkml.kernel.org/r/1390860228-21539-2-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Rik van Riel
2014-01-27 17:03:40 -05:00
committed by Ingo Molnar
parent a57beec5d4
commit 52bf84aa20
5 changed files with 1 additions and 70 deletions
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8
kernel/sched/fair.c
View File

@@ -819,14 +819,6 @@ unsigned int sysctl_numa_balancing_scan_size = 256;
/* Scan @scan_size MB every @scan_period after an initial @scan_delay in ms */
unsigned int sysctl_numa_balancing_scan_delay = 1000;
/*
* After skipping a page migration on a shared page, skip N more numa page
* migrations unconditionally. This reduces the number of NUMA migrations
* in shared memory workloads, and has the effect of pulling tasks towards
* where their memory lives, over pulling the memory towards the task.
*/
unsigned int sysctl_numa_balancing_migrate_deferred = 16;
static unsigned int task_nr_scan_windows(struct task_struct *p)
{
unsigned long rss = 0;

7
kernel/sysctl.c
View File

@@ -384,13 +384,6 @@ static struct ctl_table kern_table[] = {
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.procname = "numa_balancing_migrate_deferred",
.data = &sysctl_numa_balancing_migrate_deferred,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
#endif /* CONFIG_NUMA_BALANCING */
#endif /* CONFIG_SCHED_DEBUG */
{