From 182f3d7a02fddd9e4b1181c2ba710a930e05ddbb Mon Sep 17 00:00:00 2001 From: Muchun Song Date: Thu, 6 Aug 2020 23:26:01 -0700 Subject: [PATCH] mm/page_alloc.c: skip setting nodemask when we are in interrupt When we are in the interrupt context, it is irrelevant to the current task context. If we use current task's mems_allowed, we can be fair to alloc pages in the fast path and fall back to slow path memory allocation when the current node(which is the current task mems_allowed) does not have enough memory to allocate. In this case, it slows down the memory allocation speed of interrupt context. So we can skip setting the nodemask to allow any node to allocate memory, so that fast path allocation can success. Signed-off-by: Muchun Song Signed-off-by: Andrew Morton Reviewed-by: Pekka Enberg Cc: David Hildenbrand Link: http://lkml.kernel.org/r/20200706025921.53683-1-songmuchun@bytedance.com Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 2e49b18..9f9e15a 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -4788,7 +4788,11 @@ static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order, if (cpusets_enabled()) { *alloc_mask |= __GFP_HARDWALL; - if (!ac->nodemask) + /* + * When we are in the interrupt context, it is irrelevant + * to the current task context. It means that any node ok. + */ + if (!in_interrupt() && !ac->nodemask) ac->nodemask = &cpuset_current_mems_allowed; else *alloc_flags |= ALLOC_CPUSET; -- 2.7.4