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Diffstat (limited to 'Documentation/vm/page_owner.rst')
| -rw-r--r-- | Documentation/vm/page_owner.rst | 75 |
1 files changed, 64 insertions, 11 deletions
diff --git a/Documentation/vm/page_owner.rst b/Documentation/vm/page_owner.rst index 9837fc8147dd..c4de6f8dabe9 100644 --- a/Documentation/vm/page_owner.rst +++ b/Documentation/vm/page_owner.rst @@ -26,9 +26,9 @@ fragmentation statistics can be obtained through gfp flag information of each page. It is already implemented and activated if page owner is enabled. Other usages are more than welcome. -page owner is disabled in default. So, if you'd like to use it, you need -to add "page_owner=on" into your boot cmdline. If the kernel is built -with page owner and page owner is disabled in runtime due to no enabling +page owner is disabled by default. So, if you'd like to use it, you need +to add "page_owner=on" to your boot cmdline. If the kernel is built +with page owner and page owner is disabled in runtime due to not enabling boot option, runtime overhead is marginal. If disabled in runtime, it doesn't require memory to store owner information, so there is no runtime memory overhead. And, page owner inserts just two unlikely branches into @@ -78,33 +78,86 @@ Usage 2) Enable page owner: add "page_owner=on" to boot cmdline. -3) Do the job what you want to debug +3) Do the job that you want to debug. 4) Analyze information from page owner:: cat /sys/kernel/debug/page_owner > page_owner_full.txt ./page_owner_sort page_owner_full.txt sorted_page_owner.txt - The general output of ``page_owner_full.txt`` is as follows: + The general output of ``page_owner_full.txt`` is as follows:: Page allocated via order XXX, ... PFN XXX ... - // Detailed stack + // Detailed stack Page allocated via order XXX, ... PFN XXX ... - // Detailed stack + // Detailed stack 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 - and pages of buf, and finally sorts them according to the times. + and pages of buf, and finally sorts them according to the parameter(s). See the result about who allocated each page - in the ``sorted_page_owner.txt``. General output: + in the ``sorted_page_owner.txt``. General output:: XXX times, XXX pages: Page allocated via order XXX, ... - // Detailed stack + // Detailed stack By default, ``page_owner_sort`` is sorted according to the times of buf. - If you want to sort by the pages nums of buf, use the ``-m`` parameter. + If you want to sort by the page nums of buf, use the ``-m`` parameter. + The detailed parameters are: + + fundamental function: + + Sort: + -a Sort by memory allocation time. + -m Sort by total memory. + -p Sort by pid. + -P Sort by tgid. + -n Sort by task command name. + -r Sort by memory release time. + -s Sort by stack trace. + -t Sort by times (default). + + additional function: + + Cull: + -c Cull by comparing stacktrace instead of total block. + --cull <rules> + Specify culling rules.Culling syntax is key[,key[,...]].Choose a + multi-letter key from the **STANDARD FORMAT SPECIFIERS** section. + + + <rules> is a single argument in the form of a comma-separated list, + which offers a way to specify individual culling rules. The recognized + keywords are described in the **STANDARD FORMAT SPECIFIERS** section below. + <rules> can be specified by the sequence of keys k1,k2, ..., as described in + the STANDARD SORT KEYS section below. Mixed use of abbreviated and + complete-form of keys is allowed. + + + Examples: + ./page_owner_sort <input> <output> --cull=stacktrace + ./page_owner_sort <input> <output> --cull=st,pid,name + ./page_owner_sort <input> <output> --cull=n,f + + Filter: + -f Filter out the information of blocks whose memory has been released. + + Select: + --pid <PID> Select by pid. + --tgid <TGID> Select by tgid. + --name <command> Select by task command name. + +STANDARD FORMAT SPECIFIERS +========================== + + KEY LONG DESCRIPTION + p pid process ID + tg tgid thread group ID + n name task command name + f free whether the page has been released or not + st stacktrace stace trace of the page allocation |