From: Zhou Guanghui zhouguanghui1@huawei.com
hulk inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I612UG CVE: NA
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Since the current condition ignores the cpuset enforcement by adding __GFP_THISNODEi to the gfp_mask, this will result in allocations that specify __GFP_THISNODE and non-cdm nodes not subject to cpuset restrictions.
For example, procA pid 1000: node 0 cpus: 0 1 2 3 node 0 free: 57199MB node 1 cpus: 4 5 6 7 node 1 free: 55930MB
cpuset/test/cpuset.mems 1 cpuset/test/tasks 1000 cpuset/test/cpuset.cpus 0-3
No cdm node exists. When procA malloc 100MB memory, the result is: node 0 cpus: 0 1 2 3 node 0 free: 57099MB node 1 cpus: 4 5 6 7 node 1 free: 55930MB This is not what we expected, and in fact 100 MB of memory should be allocated from node1. The reason for this problem is that THP specifies __GFP_THISNODE to attempt to allocate from the local node.
Therefore, the cpuset enforcement should be ignored only when explicitly allocating memory from the cdm node using __GFP_ THISNODE.
Signed-off-by: Zhou Guanghui zhouguanghui1@huawei.com --- v2: fix commit message warning mm/page_alloc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index df3723c0a819..d090465de32b 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -4946,7 +4946,8 @@ static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order, ac->migratetype = gfp_migratetype(gfp_mask);
#ifdef CONFIG_COHERENT_DEVICE - if (cpusets_enabled() && !(*alloc_gfp & __GFP_THISNODE)) { + if (cpusets_enabled() && + (!(*alloc_gfp & __GFP_THISNODE) || !is_cdm_node(preferred_nid))) { #else if (cpusets_enabled()) { #endif