From: Baolin Wang baolin.wang@linux.alibaba.com
next inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I9OCYO CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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Commit 44042b449872 ("mm/page_alloc: allow high-order pages to be stored on the per-cpu lists") extends the PCP allocator to store THP pages, and it determines whether to cache THP pages in PCP by comparing with pageblock_order. But the pageblock_order is not always equal to THP order. It might also be MAX_PAGE_ORDER, which could prevent PCP from caching THP pages.
Therefore, using HPAGE_PMD_ORDER instead to determine the need for caching THP for PCP will fix this issue
Link: https://lkml.kernel.org/r/a25c9e14cd03907d5978b60546a69e6aa3fc2a7d.171215183... Fixes: 44042b449872 ("mm/page_alloc: allow high-order pages to be stored on the per-cpu lists") Signed-off-by: Baolin Wang baolin.wang@linux.alibaba.com Acked-by: Vlastimil Babka vbabka@suse.cz Cc: Mel Gorman mgorman@techsingularity.net Reviewed-by: Barry Song baohua@kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Liu Shixin liushixin2@huawei.com --- mm/page_alloc.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 95bd8f6f7889..4652dc453964 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -529,7 +529,7 @@ static inline unsigned int order_to_pindex(int migratetype, int order) { #ifdef CONFIG_TRANSPARENT_HUGEPAGE if (order > PAGE_ALLOC_COSTLY_ORDER) { - VM_BUG_ON(order != pageblock_order); + VM_BUG_ON(order != HPAGE_PMD_ORDER); return NR_LOWORDER_PCP_LISTS; } #else @@ -545,7 +545,7 @@ static inline int pindex_to_order(unsigned int pindex)
#ifdef CONFIG_TRANSPARENT_HUGEPAGE if (pindex == NR_LOWORDER_PCP_LISTS) - order = pageblock_order; + order = HPAGE_PMD_ORDER; #else VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER); #endif @@ -558,7 +558,7 @@ static inline bool pcp_allowed_order(unsigned int order) if (order <= PAGE_ALLOC_COSTLY_ORDER) return true; #ifdef CONFIG_TRANSPARENT_HUGEPAGE - if (order == pageblock_order) + if (order == HPAGE_PMD_ORDER) return true; #endif return false;