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bh=UyYy92siVxlbkOAXrPBxCpNpLxro7gVqdyR2tGshRfw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=RlH6/ki13MdccZ31W7ZNOHZHNU4dwl06XOwI2e3Zs1ynQ6VT8B2LvBFPuM4eKNb+q XtG2X2mKPQQflf5m/g4gwv8A6jrvYRbRz9V+3mWLpAYW8kWBw1GHcFpBBaHG+xcqDD tpbANPB6ufF7J7sNbeg8ps2RMyNK08Zx9kBKfZg/sAdyq/hFCi4PjFOWU6PmUmcvWQ cqSXj0BEyNspI5CBipxiw3UneGVz4VuhEIRCSxWsD03V+Is5hxLKAO1k+HE2Wo8/Ch p+HI5RtpQHx9q2+sTQVOxUB1GgprMBo6jc1y1Jem/KJdrPuoVxIGpM+nlgPdq4DKUa KUUfaDwuw3bBw== From: SJ Park To: "Gregory Price (Meta)" Cc: SJ Park , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@meta.com, akpm@linux-foundation.org, david@kernel.org, ziy@nvidia.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, ying.huang@linux.alibaba.com Subject: Re: [PATCH] mm/mempolicy: ignore a bind policy whose nodes have no memory Date: Fri, 13 Nov 2026 17:14:16 -0800 Message-ID: <20261114011417.85494-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20261113192642.2618878-1-gourry@gourry.net> References: X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=4.0.1 X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 42FDA100004 X-Stat-Signature: 45rad7q4ipqsekhomhtt8eb97ik9jhup X-Rspam-User: X-HE-Tag: 1794618865-534866 X-HE-Meta: U2FsdGVkX18jSref1wSFcguMbzJ/oZMrqUo5fdxPVfxysp/oMv3wPQpKZZl1GhVgtTKJsuPc99fp8fEV59VYCKXGYAAwpsQKvamIoedsDNVupQwcXKgATQ9Mj+/Bv8rVHpNF2owh3cF7b10CRunDpdUjRFO7/8x+L7zojYSJOlnoK1oJXNz+6QoGcS0YMH3941pH4BD9Ttm7tKppQpJenGL/IdJwj47r9BdqFQLHQqI7LpuJqGKoffIspmH92MYx0Jre1FMcEDa0pIzwp1Mzi2w1anaSPTlPJsKmwbk0bVdZFLY8nvrarM15CPpNfJaIqxi37RSUJg1w3kr86wPXIbNaiGVXIDfHkEpiBAd714hScm3GE3NkoPtk1pkrAAXu5Bd0Tp4/rkWAXzgOfm3KRXUiHjcbnxAvcn7Lzxv+AwrJ9trm6a7VaL4GbRnoUyQ//IAySJ7EFh6XdDfImvy2IJjZJq0T+UTmczCUw3wF9hpi/trNZz2CSAvuHLc0hdrgCD9x+uSzAoHDgNsmr22noLf3wzD4wVuLVLfMwEcDpO8TfbelFhkXLRSKpX+nY7ymnhEees4475LO61thj5l4m4FkyRz1ar4s5copOvNyYyFZaYwaxQuGjVAiDm+oHWLya+7ncBs8WQvjoPLY5VCsjwhDzN3bGjo9opFlXfNDfMdKO781tGUhgoXpL6+4qoqFbFfXeXz5GCxbgJq/a5peLqtAf/YN1bnkodQO2lPC4BFiQq6rIosj8gj4AIiVir2vdHEjaa5uVD/+AvC/uQ8s62HW1VswlR7h75TzdeZtEFs8/GqNLwagIakyuWAkCPkNIiepZRor78bDxttcNvEdmXscXv0heWQ+F2NEwOX3IRrmeV7nGoS84E4Si1CEGcHxxojxPdfjuXHmsjYOg2z9VDQYzCdoj+2HfNcdtSIIyYGedndmJrNeNJ3AhIlTVwArJ5nQZp1MmKdAL5aN/Kb h/XwWdSE y3w7DD2GA2Op9tZikbzCoUKvmJCMFaWi2K4llmLoHj0GMu/ixSb895WPWZFv/BBb6nLIp0enSjoV1VUUSFclRUEjJVEinuVwGGuQJDTfs1EOTa+g8IfsFzIWo1Xf+Wn4fuCZb5W8Bb+syA8j4dMJzfJ+67nDj238PFW96FnPExpK0DWyXjMghT/57AicLckchHxjjgyTv8WyFKcerh3XVK8d9y3qDD4YoHb/r/AS2/fRGfHKBSctdVCqu9y41RG7exiICEz7Bzz9Lup6hXX8PBy0G/6Oo56FVWZVOSenS5xW3rtpV3GdQ3mvE+QYQS40LH2t875DxTRdRrwKJnG0qQcpYdSk3OaUVIZpVdKmms4EPYF4= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Fri, 13 Nov 2026 14:26:42 -0500 "Gregory Price (Meta)" wrote: > apply_policy_zone() assumes that policy->nodes intersects N_MEMORY, so > it reads a bind policy with no N_HIGH_MEMORY node as movable-only. > > On systems with CONFIG_CPUSETS=n, nothing rebinds policies when memory > is removed, so offlining all memory on the nodes a bind policy names > leaves it with none. The policy is then treated as movable-only, and > movable allocations are restricted to nodes without memory. > > This results in allocations failures, a VM_FAULT_OOM leak, and then > an infinitely retrying fault that hangs the process. > > page allocation failure: order:0, mode:0x140dca ... nodemask=2 > Huh VM_FAULT_OOM leaked out to the #PF handler. Retrying PF > > Ignore a bind policy whose nodes have no memory. policy_nodemask() > already ignores a bind policy that does not intersect the cpuset. > This covers hugetlb's policy_mbind_nodemask() as well. > > If the nodes regain memory, the policy applies again. > > CPUSETS=n with HOTREMOVE=y is unlikely a common configuration, so this > isn't marked for stable. Makes sense and looks good to me. > > Signed-off-by: Gregory Price (Meta) Reviewed-by: SJ Park Thanks, SJ [...]