• Mel Gorman's avatar
    tracing, page-allocator: add trace events for page allocation and page freeing · 4b4f278c
    Mel Gorman authored
    This patch adds trace events for the allocation and freeing of pages,
    including the freeing of pagevecs.  Using the events, it will be known
    what struct page and pfns are being allocated and freed and what the call
    site was in many cases.
    The page alloc tracepoints be used as an indicator as to whether the
    workload was heavily dependant on the page allocator or not.  You can make
    a guess based on vmstat but you can't get a per-process breakdown.
    Depending on the call path, the call_site for page allocation may be
    __get_free_pages() instead of a useful callsite.  Instead of passing down
    a return address similar to slab debugging, the user should enable the
    stacktrace and seg-addr options to get a proper stack trace.
    The pagevec free tracepoint has a different usecase.  It can be used to
    get a idea of how many pages are being dumped off the LRU and whether it
    is kswapd doing the work or a process doing direct reclaim.
    Signed-off-by: default avatarMel Gorman <mel@csn.ul.ie>
    Acked-by: default avatarRik van Riel <riel@redhat.com>
    Reviewed-by: default avatarIngo Molnar <mingo@elte.hu>
    Cc: Larry Woodman <lwoodman@redhat.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Li Ming Chun <macli@brc.ubc.ca>
    Reviewed-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
page_alloc.c 137 KB