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author | Barry Song <v-songbaohua@oppo.com> | 2024-04-12 14:48:57 +0300 |
---|---|---|
committer | Andrew Morton <akpm@linux-foundation.org> | 2024-05-06 03:53:36 +0300 |
commit | 42248b9d34ea1be1b959d343fff465906cb787fc (patch) | |
tree | 1e1774be22d374796dd924ad57ad1bde178b3c5d /Documentation/admin-guide | |
parent | d0f048ac39f6a71566d3f49a5922dfd7fa0d585b (diff) | |
download | linux-42248b9d34ea1be1b959d343fff465906cb787fc.tar.xz |
mm: add docs for per-order mTHP counters and transhuge_page ABI
This patch includes documentation for mTHP counters and an ABI file for
sys-kernel-mm-transparent-hugepage, which appears to have been missing for
some time.
[v-songbaohua@oppo.com: fix the name and unexpected indentation]
Link: https://lkml.kernel.org/r/20240415054538.17071-1-21cnbao@gmail.com
Link: https://lkml.kernel.org/r/20240412114858.407208-4-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'Documentation/admin-guide')
-rw-r--r-- | Documentation/admin-guide/mm/transhuge.rst | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst index 04eb45a2f940..e0fe17affeb3 100644 --- a/Documentation/admin-guide/mm/transhuge.rst +++ b/Documentation/admin-guide/mm/transhuge.rst @@ -447,6 +447,34 @@ thp_swpout_fallback Usually because failed to allocate some continuous swap space for the huge page. +In /sys/kernel/mm/transparent_hugepage/hugepages-<size>kB/stats, There are +also individual counters for each huge page size, which can be utilized to +monitor the system's effectiveness in providing huge pages for usage. Each +counter has its own corresponding file. + +anon_fault_alloc + is incremented every time a huge page is successfully + allocated and charged to handle a page fault. + +anon_fault_fallback + is incremented if a page fault fails to allocate or charge + a huge page and instead falls back to using huge pages with + lower orders or small pages. + +anon_fault_fallback_charge + is incremented if a page fault fails to charge a huge page and + instead falls back to using huge pages with lower orders or + small pages even though the allocation was successful. + +anon_swpout + is incremented every time a huge page is swapped out in one + piece without splitting. + +anon_swpout_fallback + is incremented if a huge page has to be split before swapout. + Usually because failed to allocate some continuous swap space + for the huge page. + 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 |