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authorRik van Riel <riel@redhat.com>2014-01-27 17:03:40 -0500
committerIngo Molnar <mingo@kernel.org>2014-01-28 13:17:04 +0100
commit52bf84aa206cd2c2516dfa3e03b578edf8a3242f (patch)
treee8acbb2c3ce90b7aed27046c7efc5a082f6ef684 /kernel
parenta57beec5d427086cdc8d75fd51164577193fa7f4 (diff)
sched/numa, mm: Remove p->numa_migrate_deferred
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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched/fair.c8
-rw-r--r--kernel/sysctl.c7
2 files changed, 0 insertions, 15 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index efe6457ac5c8..7cdde913b4dc 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -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;
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index c8da99f905cf..b41d61d95c14 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -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 */
{