Messages in this thread | | | From | Zi Yan <> | Subject | Re: [PATCH 3/6] mm: page_alloc: move free pages when converting block during isolation | Date | Mon, 11 Sep 2023 16:17:07 -0400 |
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On 11 Sep 2023, at 15:41, Johannes Weiner wrote:
> When claiming a block during compaction isolation, move any remaining > free pages to the correct freelists as well, instead of stranding them > on the wrong list. Otherwise, this encourages incompatible page mixing > down the line, and thus long-term fragmentation. > > Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> > --- > mm/page_alloc.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 3db405414174..f6f658c3d394 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -2548,9 +2548,12 @@ int __isolate_free_page(struct page *page, unsigned int order) > * Only change normal pageblocks (i.e., they can merge > * with others) > */ > - if (migratetype_is_mergeable(mt)) > + if (migratetype_is_mergeable(mt)) { > set_pageblock_migratetype(page, > MIGRATE_MOVABLE); > + move_freepages_block(zone, page, > + MIGRATE_MOVABLE, NULL); > + } > } > } > > -- > 2.42.0
Is this needed? And is this correct?
__isolate_free_page() removes the free page from a free list, but the added move_freepages_block() puts the page back to another free list, making __isolate_free_page() not do its work. OK. the for loop is going through the pages within the pageblock, so move_freepages_block() should be used on the rest of the pages on the pageblock.
So to make this correct, the easies change might be move del_page_from_free_list(page, zone, order) below this code chunk.
-- Best Regards, Yan, Zi [unhandled content-type:application/pgp-signature] | |