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    SubjectRe: [PATCH v5 1/5] mm,page_alloc: Bail out earlier on -ENOMEM in alloc_contig_migrate_range
    On Wed, Mar 17, 2021 at 03:05:40PM +0100, Michal Hocko wrote:
    > That being said, bailing out early makes sense to me. But now that
    > you've made me look into the migrate_pages excellent error state reporting
    > I suspect we have a bug here. Note the
    > "Returns the number of pages that were not migrated, or an error code."
    >
    > but I do not see putback_movable_pages for ret > 0 so it seems we might
    > leak some pages.

    I fell for the same thing when looking at that code.
    It took a while until I realized what was really going on.

    > > Signed-off-by: Oscar Salvador <osalvador@suse.de>
    > > Acked-by: Vlastimil Babka <vbabka@suse.cz>
    > > Reviewed-by: David Hildenbrand <david@redhat.com>
    >
    > The patch itself looks reasonable but make sure to mention this is mere
    > cosmetic change unless there is a real problem fixed by this.
    > Acked-by: Michal Hocko <mhocko@suse.com>

    What about appending the following in the changelog:

    "Note that this is not fixing a real issue, just a cosmetic change. Although
    we can save some cycles by backing off ealier."


    --
    Oscar Salvador
    SUSE L3

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