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GET /api/1.1/patches/2230788/?format=api
{ "id": 2230788, "url": "http://patchwork.ozlabs.org/api/1.1/patches/2230788/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linuxppc-dev/patch/20260430040427.4672-5-baohua@kernel.org/", "project": { "id": 2, "url": "http://patchwork.ozlabs.org/api/1.1/projects/2/?format=api", "name": "Linux PPC development", "link_name": "linuxppc-dev", "list_id": "linuxppc-dev.lists.ozlabs.org", "list_email": "linuxppc-dev@lists.ozlabs.org", "web_url": "https://github.com/linuxppc/wiki/wiki", "scm_url": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git", "webscm_url": "https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/" }, "msgid": "<20260430040427.4672-5-baohua@kernel.org>", "date": "2026-04-30T04:04:26", "name": "[v2,4/5] mm: Don't retry page fault if folio is uptodate during swap-in", "commit_ref": null, "pull_url": null, "state": "handled-elsewhere", "archived": false, "hash": "d4ff5396b36456015d1ff1f7c486b4e1e503e87c", "submitter": { "id": 48512, "url": "http://patchwork.ozlabs.org/api/1.1/people/48512/?format=api", "name": "Barry Song", "email": "baohua@kernel.org" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/linuxppc-dev/patch/20260430040427.4672-5-baohua@kernel.org/mbox/", "series": [ { "id": 502184, "url": "http://patchwork.ozlabs.org/api/1.1/series/502184/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=502184", "date": "2026-04-30T04:04:27", "name": "mm: reduce mmap_lock contention and improve page fault performance", "version": 2, "mbox": "http://patchwork.ozlabs.org/series/502184/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2230788/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2230788/checks/", "tags": {}, "headers": { "Return-Path": "\n <linuxppc-dev+bounces-20327-incoming=patchwork.ozlabs.org@lists.ozlabs.org>", "X-Original-To": [ "incoming@patchwork.ozlabs.org", "linuxppc-dev@lists.ozlabs.org" ], "Delivered-To": "patchwork-incoming@legolas.ozlabs.org", "Authentication-Results": [ "legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256\n header.s=k20201202 header.b=uJyCN/cP;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org\n (client-ip=2404:9400:21b9:f100::1; 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a=rsa-sha256; c=relaxed/simple; d=kernel.org;\n\ts=k20201202; t=1777521914;\n\tbh=6MPYWPf1QbIXw7VCTkYtFV9yBQTJYYcQnuchAn2u66s=;\n\th=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n\tb=uJyCN/cPD0/zuU5TMG/FWh17eVTVcTCG22wyND+Ln22vdCzvScs+KeOLVG9RmOssZ\n\t jDw1d8PhCAGGbMI/IFgx4Z5EBNcmkVO03z+9/CJtVz3K4wxUxjDLHuhXQrygfZY0vj\n\t Mz9EPYWMtvXMUkv1GvrXcIXqYy7f2Nbz3f61nlophvJmqpD4ikN6UOlFyXJonZi3kU\n\t apK9iwjy49sl7fMM6lNjIBPwaa1bmY1pG/z4xtRWqVUh4kt9XKZhnZLwyhRWE61vDF\n\t fxzmTVdxergJndpikZIoTxLjBRYHAUamicyvLwT/yqUnIVLaZSAeOqCic0yYJ36c4O\n\t EWCGitvEei8LA==", "From": "\"Barry Song (Xiaomi)\" <baohua@kernel.org>", "To": "akpm@linux-foundation.org,\n\tlinux-mm@kvack.org,\n\twilly@infradead.org", "Cc": "david@kernel.org,\n\tljs@kernel.org,\n\tliam@infradead.org,\n\tvbabka@kernel.org,\n\trppt@kernel.org,\n\tsurenb@google.com,\n\tmhocko@suse.com,\n\tjack@suse.cz,\n\tpfalcato@suse.de,\n\twanglian@kylinos.cn,\n\tchentao@kylinos.cn,\n\tlianux.mm@gmail.com,\n\tkunwu.chan@gmail.com,\n\tliyangouwen1@oppo.com,\n\tchrisl@kernel.org,\n\tkasong@tencent.com,\n\tshikemeng@huaweicloud.com,\n\tnphamcs@gmail.com,\n\tbhe@redhat.com,\n\tyoungjun.park@lge.com,\n\tlinux-arm-kernel@lists.infradead.org,\n\tlinux-kernel@vger.kernel.org,\n\tloongarch@lists.linux.dev,\n\tlinuxppc-dev@lists.ozlabs.org,\n\tlinux-riscv@lists.infradead.org,\n\tlinux-s390@vger.kernel.org,\n\t\"Barry Song (Xiaomi)\" <baohua@kernel.org>", "Subject": "[PATCH v2 4/5] mm: Don't retry page fault if folio is uptodate during\n swap-in", "Date": "Thu, 30 Apr 2026 12:04:26 +0800", "Message-Id": "<20260430040427.4672-5-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": "<linuxppc-dev.lists.ozlabs.org>", "List-Help": "<mailto:linuxppc-dev+help@lists.ozlabs.org>", "List-Owner": "<mailto:linuxppc-dev+owner@lists.ozlabs.org>", "List-Post": "<mailto:linuxppc-dev@lists.ozlabs.org>", "List-Archive": "<https://lore.kernel.org/linuxppc-dev/>,\n <https://lists.ozlabs.org/pipermail/linuxppc-dev/>", "List-Subscribe": "<mailto:linuxppc-dev+subscribe@lists.ozlabs.org>,\n <mailto:linuxppc-dev+subscribe-digest@lists.ozlabs.org>,\n <mailto:linuxppc-dev+subscribe-nomail@lists.ozlabs.org>", "List-Unsubscribe": "<mailto:linuxppc-dev+unsubscribe@lists.ozlabs.org>", "Precedence": "list", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "X-Spam-Status": "No, score=-0.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED,\n\tDKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS\n\tautolearn=disabled version=4.0.1 OzLabs 8", "X-Spam-Checker-Version": "SpamAssassin 4.0.1 (2024-03-25) on lists.ozlabs.org" }, "content": "If we are waiting for long I/O to complete, it makes sense to\navoid holding locks for too long. However, if the folio is\nuptodate, we are likely only waiting for a concurrent PTE\nupdate to finish. Retrying the entire page fault seems\nexcessive.\n\nSigned-off-by: Barry Song (Xiaomi) <baohua@kernel.org>\n---\n mm/memory.c | 7 +++++++\n 1 file changed, 7 insertions(+)", "diff": "diff --git a/mm/memory.c b/mm/memory.c\nindex 0c740ca363cc..a2e4f2d87ec8 100644\n--- a/mm/memory.c\n+++ b/mm/memory.c\n@@ -4949,6 +4949,13 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)\n \t}\n \n \tswapcache = folio;\n+\t/*\n+\t * If the folio is uptodate, we are likely only waiting for\n+\t * another concurrent PTE mapping to complete, which should\n+\t * be brief. No need to drop the lock and retry the fault.\n+\t */\n+\tif (folio_test_uptodate(folio))\n+\t\tvmf->flags &= ~FAULT_FLAG_ALLOW_RETRY;\n \tret |= folio_lock_or_retry(folio, vmf);\n \tif (ret & VM_FAULT_RETRY) {\n \t\tif (fault_flag_allow_retry_first(vmf->flags) &&\n", "prefixes": [ "v2", "4/5" ] }