diff options
| -rw-r--r-- | Documentation/vm/transhuge.txt | 8 | ||||
| -rw-r--r-- | include/linux/vm_event_item.h | 2 | ||||
| -rw-r--r-- | mm/huge_memory.c | 5 | ||||
| -rw-r--r-- | mm/vmstat.c | 2 |
4 files changed, 16 insertions, 1 deletions
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 @@ retry: 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 */ |