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Thu, 30 Apr 2026 04:05:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777521919; bh=pbXcAk16+rZv3mixELQ0Ipha1GpoRaVFtegxsWu8Zqk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ocBfK8O4Ywas1DnfVulkPf8JAygFLLLSXfSSIhFab5aPydgPGyQRMZl4VC0fcDxzh ZSF8ZjBo9bGMKXhwl/M9RckUdNTcuoEDs1sQYC8HxwbacO47214ueIB5PuN5R9qPyl 7/vXQCjK6DhEeLKCFGPA8mBl5pi8Xir7/uhc151Nze4/YpDG2oez+rIhbMYqevbaCB eLjkznrbZrf9uMIIMqF0/apYtZGMqURcRmb3l4AFBitMcYEDgyMeHrj8n9yVB0vf4O no7KHvYOh/5gIxhaiyHe3dpMaQbh59rmzxY6J3CuNafpQ/IRafc5BIkfCVPTmXqOYt bTDK/08BVuABA== From: "Barry Song (Xiaomi)" To: akpm@linux-foundation.org, linux-mm@kvack.org, willy@infradead.org Cc: david@kernel.org, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, jack@suse.cz, pfalcato@suse.de, wanglian@kylinos.cn, chentao@kylinos.cn, lianux.mm@gmail.com, kunwu.chan@gmail.com, liyangouwen1@oppo.com, chrisl@kernel.org, kasong@tencent.com, shikemeng@huaweicloud.com, nphamcs@gmail.com, bhe@redhat.com, youngjun.park@lge.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, "Barry Song (Xiaomi)" Subject: [PATCH v2 5/5] mm/filemap: Avoid retrying page faults on uptodate folios in filemap faults Date: Thu, 30 Apr 2026 12:04:27 +0800 Message-Id: <20260430040427.4672-6-baohua@kernel.org> X-Mailer: git-send-email 2.39.3 (Apple Git-146) In-Reply-To: <20260430040427.4672-1-baohua@kernel.org> References: <20260430040427.4672-1-baohua@kernel.org> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit For uptodate folios, we are not waiting on I/O. We should be able to acquire the folio lock shortly, so there is no need to drop per-vma locks and perform a full PF retry. Signed-off-by: Barry Song (Xiaomi) --- mm/filemap.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/mm/filemap.c b/mm/filemap.c index b532d6cbafc8..0d2f6af5d0fe 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -3533,6 +3533,13 @@ vm_fault_t filemap_fault(struct vm_fault *vmf) } } + /* + * If the folio is uptodate, we are likely only waiting for + * another concurrent PTE mapping to complete, which should + * be brief. No need to drop the lock and retry the fault. + */ + if (folio_test_uptodate(folio)) + vmf->flags &= ~FAULT_FLAG_ALLOW_RETRY; if (!lock_folio_maybe_drop_mmap(vmf, folio, &fpin)) goto out_retry; -- 2.39.3 (Apple Git-146)