lkml.org 
[lkml]   [2022]   [Jul]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH -V2 3/7] migrate_pages(): fix THP failure counting for -ENOMEM
    Date
    In unmap_and_move(), if the new THP cannot be allocated, -ENOMEM will
    be returned, and migrate_pages() will try to split the THP unless
    "reason" is MR_NUMA_MISPLACED (that is, nosplit == true). But when
    nosplit == true, the THP migration failure will not be counted. This
    is incorrect. So in this patch, the THP migration failure will be
    counted for -ENOMEM regardless of nosplit is true or false. The
    nr_failed counting isn't fixed because it's not used. Added some
    comments for it per Baolin's suggestion.

    Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
    Fixes: 5984fabb6e82 ("mm: move_pages: report the number of non-attempted pages")
    Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
    Cc: Zi Yan <ziy@nvidia.com>
    Cc: Yang Shi <shy828301@gmail.com>
    ---
    mm/migrate.c | 7 ++++---
    1 file changed, 4 insertions(+), 3 deletions(-)

    diff --git a/mm/migrate.c b/mm/migrate.c
    index 794312072eb3..38e2c789a9c3 100644
    --- a/mm/migrate.c
    +++ b/mm/migrate.c
    @@ -1426,11 +1426,11 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page,
    /*
    * When memory is low, don't bother to try to migrate
    * other pages, just exit.
    - * THP NUMA faulting doesn't split THP to retry.
    */
    - if (is_thp && !nosplit) {
    + if (is_thp) {
    nr_thp_failed++;
    - if (!try_split_thp(page, &thp_split_pages)) {
    + /* THP NUMA faulting doesn't split THP to retry. */
    + if (!nosplit && !try_split_thp(page, &thp_split_pages)) {
    nr_thp_split++;
    goto retry;
    }
    @@ -1446,6 +1446,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page,
    * the caller otherwise the page refcnt will be leaked.
    */
    list_splice_init(&thp_split_pages, from);
    + /* nr_failed isn't updated for not used */
    nr_thp_failed += thp_retry;
    goto out;
    case -EAGAIN:
    --
    2.30.2
    \
     
     \ /
      Last update: 2022-07-11 10:51    [W:4.505 / U:0.308 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site