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Diffstat (limited to '')
| -rw-r--r-- | Documentation/mm/page_owner.rst | 25 |
1 files changed, 9 insertions, 16 deletions
diff --git a/Documentation/mm/page_owner.rst b/Documentation/mm/page_owner.rst index f5c954afe97c..127514955a5e 100644 --- a/Documentation/mm/page_owner.rst +++ b/Documentation/mm/page_owner.rst @@ -38,22 +38,10 @@ not affect to allocation performance, especially if the static keys jump label patching functionality is available. Following is the kernel's code size change due to this facility. -- Without page owner:: - - text data bss dec hex filename - 48392 2333 644 51369 c8a9 mm/page_alloc.o - -- With page owner:: - - text data bss dec hex filename - 48800 2445 644 51889 cab1 mm/page_alloc.o - 6662 108 29 6799 1a8f mm/page_owner.o - 1025 8 8 1041 411 mm/page_ext.o - -Although, roughly, 8 KB code is added in total, page_alloc.o increase by -520 bytes and less than half of it is in hotpath. Building the kernel with -page owner and turning it on if needed would be great option to debug -kernel memory problem. +Although enabling page owner increases kernel size by several kilobytes, +most of this code is outside page allocator and its hot path. Building +the kernel with page owner and turning it on if needed would be great +option to debug kernel memory problem. There is one notice that is caused by implementation detail. page owner stores information into the memory from struct page extension. This memory @@ -94,6 +82,11 @@ Usage Page allocated via order XXX, ... PFN XXX ... // Detailed stack + By default, it will do full pfn dump, to start with a given pfn, + page_owner supports fseek. + + FILE *fp = fopen("/sys/kernel/debug/page_owner", "r"); + fseek(fp, pfn_start, SEEK_SET); The ``page_owner_sort`` tool ignores ``PFN`` rows, puts the remaining rows in buf, uses regexp to extract the page order value, counts the times |