Messages in this thread Patch in this message | | | From | Gilad Ben-Yossef <> | Subject | [v7 8/8] mm: add vmstat counters for tracking PCP drains | Date | Thu, 26 Jan 2012 12:02:01 +0200 |
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This patch introduces two new vmstat counters for testing purposes: pcp_global_drain that counts the number of times a per-cpu pages global drain was requested and pcp_global_ipi_saved that counts the number of times the number of CPUs with per-cpu pages in any zone were less then 1/2 of the number of online CPUs.
The patch purpose is to show the usefulness of only sending an IPI asking to drain per-cpu pages to CPUs that actually have them instead of a blind global IPI. It is probably not useful by itself.
Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com> CC: Christoph Lameter <cl@linux.com> CC: Chris Metcalf <cmetcalf@tilera.com> CC: Peter Zijlstra <a.p.zijlstra@chello.nl> CC: Frederic Weisbecker <fweisbec@gmail.com> CC: linux-mm@kvack.org CC: Pekka Enberg <penberg@kernel.org> CC: Matt Mackall <mpm@selenic.com> CC: Sasha Levin <levinsasha928@gmail.com> CC: Rik van Riel <riel@redhat.com> CC: Andi Kleen <andi@firstfloor.org> CC: Mel Gorman <mel@csn.ul.ie> CC: Andrew Morton <akpm@linux-foundation.org> CC: Alexander Viro <viro@zeniv.linux.org.uk> CC: Avi Kivity <avi@redhat.com> CC: Michal Nazarewicz <mina86@mina86.com> CC: Kosaki Motohiro <kosaki.motohiro@gmail.com> CC: Milton Miller <miltonm@bga.com> --- include/linux/vm_event_item.h | 1 + mm/page_alloc.c | 5 +++++ mm/vmstat.c | 2 ++ 3 files changed, 8 insertions(+), 0 deletions(-)
diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h index 03b90cd..3657f6f 100644 --- a/include/linux/vm_event_item.h +++ b/include/linux/vm_event_item.h @@ -58,6 +58,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, THP_COLLAPSE_ALLOC_FAILED, THP_SPLIT, #endif + PCP_GLOBAL_DRAIN, PCP_GLOBAL_IPI_SAVED, NR_VM_EVENT_ITEMS }; diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 4135983..1aa9031 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1195,6 +1195,11 @@ void drain_all_pages(void) cpumask_clear_cpu(cpu, &cpus_with_pcps); } on_each_cpu_mask(&cpus_with_pcps, drain_local_pages, NULL, 1); + + count_vm_event(PCP_GLOBAL_DRAIN); + if (cpumask_weight(&cpus_with_pcps) < + (cpumask_weight(cpu_online_mask) / 2)) + count_vm_event(PCP_GLOBAL_IPI_SAVED); } #ifdef CONFIG_HIBERNATION diff --git a/mm/vmstat.c b/mm/vmstat.c index f600557..3ee5f99 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -786,6 +786,8 @@ const char * const vmstat_text[] = { "thp_collapse_alloc_failed", "thp_split", #endif + "pcp_global_drain", + "pcp_global_ipi_saved" #endif /* CONFIG_VM_EVENTS_COUNTERS */ }; -- 1.7.0.4
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