On 29 Oct 2020, at 20:28, Andrew Morton wrote: > On Thu, 29 Oct 2020 17:31:28 -0400 Zi Yan <ziy@xxxxxxxxxx> wrote: > >>> >>> Shall you add Fixes tag to commit >>> 1da2f328fa643bd72197dfed0c655148af31e4eb? And may cc stable. >> >> Sure. >> >> Fixes: 1da2f328fa64 (“mm,thp,compaction,cma: allow THP migration for CMA allocations”) >> >> stable cc'ed. > > A think a cc:stable really requires a description of the end-user > visible effects of the bug. Could you please provide that? Sure. For example, in a system with 16GB memory and an 8GB CMA region reserved by hugetlb_cma, if we first allocate 10GB THPs and mlock them (so some THPs are allocated in the CMA region and mlocked), reserving 6 1GB hugetlb pages via /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages will get stuck (looping in too_many_isolated function) until we kill either task. With the patch applied, oom will kill the application with 10GB THPs and let hugetlb page reservation finish. — Best Regards, Yan Zi
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