From 3b077c13d3e17aa73f0b7261c6a0838e07e06d7f Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Thu, 29 Nov 2012 14:18:01 +1100 Subject: [PATCH] thp, vmstat: implement HZP_ALLOC and HZP_ALLOC_FAILED events hzp_alloc is incremented every time a huge zero page is successfully allocated. It includes allocations which where dropped due race with other allocation. Note, it doesn't count every map of the huge zero page, only its allocation. hzp_alloc_failed is incremented if kernel fails to allocate huge zero page and falls back to using small pages. Signed-off-by: Kirill A. Shutemov Cc: Andrea Arcangeli Cc: Andi Kleen Cc: "H. Peter Anvin" Cc: Mel Gorman Cc: David Rientjes Signed-off-by: Andrew Morton --- Documentation/vm/transhuge.txt | 8 ++++++++ include/linux/vm_event_item.h | 2 ++ mm/huge_memory.c | 5 ++++- mm/vmstat.c | 2 ++ 4 files changed, 16 insertions(+), 1 deletion(-) diff --git a/Documentation/vm/transhuge.txt b/Documentation/vm/transhuge.txt index 8f5b41db314c..197e93d34c96 100644 --- a/Documentation/vm/transhuge.txt +++ b/Documentation/vm/transhuge.txt @@ -197,6 +197,14 @@ thp_split is incremented every time a huge page is split into base pages. This can happen for a variety of reasons but a common reason is that a huge page is old and is being reclaimed. +hzp_alloc is incremented every time a huge zero page is successfully + allocated. It includes allocations which where dropped due + race with other allocation. Note, it doesn't count every map + of the huge zero page, only its allocation. + +hzp_alloc_failed is incremented if kernel fails to allocate huge zero + page and falls back to using small pages. + As the system ages, allocating huge pages may be expensive as the system uses memory compaction to copy data around memory to free a huge page for use. There are some counters in /proc/vmstat to help diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h index bd67c3f79b4e..de74d6e0212e 100644 --- a/include/linux/vm_event_item.h +++ b/include/linux/vm_event_item.h @@ -63,6 +63,8 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, THP_COLLAPSE_ALLOC, THP_COLLAPSE_ALLOC_FAILED, THP_SPLIT, + HZP_ALLOC, + HZP_ALLOC_FAILED, #endif NR_VM_EVENT_ITEMS }; diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 0b841d315262..fc00c064df22 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -185,8 +185,11 @@ retry: zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, HPAGE_PMD_ORDER); - if (!zero_page) + if (!zero_page) { + count_vm_event(HZP_ALLOC_FAILED); return 0; + } + count_vm_event(HZP_ALLOC); preempt_disable(); if (cmpxchg(&huge_zero_pfn, 0, page_to_pfn(zero_page))) { preempt_enable(); diff --git a/mm/vmstat.c b/mm/vmstat.c index 18a76ea6d012..e931e1daa9aa 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -808,6 +808,8 @@ const char * const vmstat_text[] = { "thp_collapse_alloc", "thp_collapse_alloc_failed", "thp_split", + "hzp_alloc", + "hzp_alloc_failed", #endif #endif /* CONFIG_VM_EVENTS_COUNTERS */ -- 2.39.5