From d8a8e1f0da3d29d7268b3300c96a059d63901b76 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Wed, 12 Dec 2012 13:51:09 -0800 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 Signed-off-by: Linus Torvalds --- 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..60aeedd54615 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. +thp_zero_page_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. + +thp_zero_page_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 3d3114594370..fe786f07d2bd 100644 --- a/include/linux/vm_event_item.h +++ b/include/linux/vm_event_item.h @@ -58,6 +58,8 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, THP_COLLAPSE_ALLOC, THP_COLLAPSE_ALLOC_FAILED, THP_SPLIT, + THP_ZERO_PAGE_ALLOC, + THP_ZERO_PAGE_ALLOC_FAILED, #endif NR_VM_EVENT_ITEMS }; diff --git a/mm/huge_memory.c b/mm/huge_memory.c index d89220cb1d9f..9a5d45dfad44 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -184,8 +184,11 @@ static unsigned long get_huge_zero_page(void) zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, HPAGE_PMD_ORDER); - if (!zero_page) + if (!zero_page) { + count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); return 0; + } + count_vm_event(THP_ZERO_PAGE_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 c7370579111b..5da4b19023c3 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -801,6 +801,8 @@ const char * const vmstat_text[] = { "thp_collapse_alloc", "thp_collapse_alloc_failed", "thp_split", + "thp_zero_page_alloc", + "thp_zero_page_alloc_failed", #endif #endif /* CONFIG_VM_EVENTS_COUNTERS */