From d235a154899abbbc6aad6615a38bd3728a905208 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Thu, 5 Dec 2024 10:05:07 +0100 Subject: [PATCH] mm/page_alloc: don't use __GFP_HARDWALL when migrating pages via alloc_contig*() Patch series "mm: don't use __GFP_HARDWALL when migrating remote pages". __GFP_HARDWALL means that we will be respecting the cpuset of the caller when allocating a page. However, when we are migrating remote allocations (pages allocated from other context), the cpuset of the current context is irrelevant. For memory offlining + alloc_contig_*(), this is rather obvious. There might be other such page migration users, let's start with the obvious ones. This patch (of 2): We'll migrate pages allocated by other contexts; respecting the cpuset of the alloc_contig*() caller when allocating a migration target does not make sense. Drop the __GFP_HARDWALL. Note that in an ideal world, migration code could figure out the cpuset of the original context and take that into consideration. Link: https://lkml.kernel.org/r/20241205090508.2095225-1-david@redhat.com Link: https://lkml.kernel.org/r/20241205090508.2095225-2-david@redhat.com Signed-off-by: David Hildenbrand Suggested-by: Vlastimil Babka Reviewed-by: Vlastimil Babka Reviewed-by: Oscar Salvador Cc: Zi Yan Signed-off-by: Andrew Morton --- 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 a52c6022c65c..dde19db204b2 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6412,11 +6412,11 @@ static int __alloc_contig_verify_gfp_mask(gfp_t gfp_mask, gfp_t *gfp_cc_mask) * page range. Migratable pages are movable, __GFP_MOVABLE is implied * for them. * - * Traditionally we always had __GFP_HARDWALL|__GFP_RETRY_MAYFAIL set, - * keep doing that to not degrade callers. + * Traditionally we always had __GFP_RETRY_MAYFAIL set, keep doing that + * to not degrade callers. */ *gfp_cc_mask = (gfp_mask & (reclaim_mask | cc_action_mask)) | - __GFP_HARDWALL | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL; + __GFP_MOVABLE | __GFP_RETRY_MAYFAIL; return 0; }