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Received: from localhost(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0XAj7wOz_1789099483 cluster:ay36) by smtp.aliyun-inc.com; Fri, 11 Sep 2026 12:04:43 +0800 From: Baolin Wang To: akpm@linux-foundation.org, hughd@google.com, david@kernel.org Cc: ziy@nvidia.com, liam@infradead.org, nico.pache@linux.dev, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, usama.arif@linux.dev, kas@kernel.org, ljs@kernel.org, baolin.wang@linux.alibaba.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH] mm: shmem: ignore sysfs configs for shmem forced collapse Date: Fri, 11 Sep 2026 12:04:33 +0800 Message-ID: X-Mailer: git-send-email 2.43.5 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: E2D79A0002 X-Stat-Signature: u984twgjwxat9mbxahup3rnriofrb7oq X-Rspam-User: X-HE-Tag: 1789099488-423950 X-HE-Meta: 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 Hz7IkZSE W8BttqlKxfjCOVLpLgf5C5SL9KSqm0y09tg0FxJGLJq9wIulC10ruCkyQdh701Zomt3GHF2tOE6iD5g1mxdCvsVDOidsvkOuQagIh3pk3Gs6v18rqX4TEF1ph8ppy3nnvwvyyh4b0ukekSbh/Rt788Z2HBkeHJACq6aF2LuYlHLLEdW9BI1TIh4/hnmKQwlvxur4cul4eVaG9bayXT/hXPTmlbNeMAciZ0T1mz8LEc5Kroo6iLDNO9FsP+RgZVn/eJtIMr4u2PSayFVxe/o4PFqohgg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: According to Documentation/mm/transhuge.rst, MADV_COLLAPSE is expected to ignore any THP or mTHP interface settings. However, after commit 6beeab870e70 ("mm: shmem: move shmem_huge_global_enabled() into shmem_allowable_huge_orders()"), performing MADV_COLLAPSE on shmem will depend on /sys/.../hugepages-2048kB/shmem_enabled being set to "inherit" (although that is the default), which can cause MADV_COLLAPSE to fail unexpectedly. Fix this by returning the result of shmem_huge_global_enabled() directly when MADV_COLLAPSE is requested, allowing PMD-order collapse while ignoring shmem THP/mTHP settings. Fixes: 6beeab870e70 ("mm: shmem: move shmem_huge_global_enabled() into shmem_allowable_huge_orders()") Reported-by: Kiryl Shutsemau (Meta) Closes: https://lore.kernel.org/all/20260908125105.1510704-7-kirill@shutemov.name/ Signed-off-by: Baolin Wang --- Hi Kiryl, I did not update the selftests, as I hope this fix will be merged first. After this fix has landed, I can send a patch to update the selftests. --- mm/shmem.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index c92ed17dbc4a..b572c60f2af8 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2049,8 +2049,11 @@ unsigned long shmem_allowable_huge_orders(struct inode *inode, global_orders = shmem_huge_global_enabled(inode, index, write_end, shmem_huge_force, vma, vm_flags); - /* Tmpfs huge pages allocation */ - if (!vma || !vma_is_anon_shmem(vma)) + /* + * Tmpfs huge pages allocation or forced collapse ignores + * sysfs configs. + */ + if (!vma || !vma_is_anon_shmem(vma) || shmem_huge_force) return global_orders; /* -- 2.47.3