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Fri, 19 Dec 2025 11:44:40 -0800 (PST) Received: from [127.0.0.1] ([101.32.222.185]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2a2f3d76ceesm30170985ad.91.2025.12.19.11.44.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 19 Dec 2025 11:44:40 -0800 (PST) From: Kairui Song Date: Sat, 20 Dec 2025 03:43:34 +0800 Subject: [PATCH v5 05/19] mm, swap: simplify the code and reduce indention MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20251220-swap-table-p2-v5-5-8862a265a033@tencent.com> References: <20251220-swap-table-p2-v5-0-8862a265a033@tencent.com> In-Reply-To: <20251220-swap-table-p2-v5-0-8862a265a033@tencent.com> To: linux-mm@kvack.org Cc: Andrew Morton , Baoquan He , Barry Song , Chris Li , Nhat Pham , Yosry Ahmed , David Hildenbrand , Johannes Weiner , Youngjun Park , Hugh Dickins , Baolin Wang , Ying Huang , Kemeng Shi , Lorenzo Stoakes , "Matthew Wilcox (Oracle)" , linux-kernel@vger.kernel.org, Kairui Song X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1766173451; l=4358; i=kasong@tencent.com; s=kasong-sign-tencent; h=from:subject:message-id; bh=WUlfqihUv3ek+SR5ujgLz5PJkzf/2opJSuBs8ZAe3co=; b=5zhzoyx9NhY5k8vy0xE845tIjN0SJyVbaayX0A9+sCQM/9BpbC2Wev4bEf8+OrAh1BYgpzVEQ x+ACNzZBtbLDjPpCsNLDna8i2F8PX7MlhrwS7H0O5mv4yfWltV71Xmw X-Developer-Key: i=kasong@tencent.com; a=ed25519; pk=kCdoBuwrYph+KrkJnrr7Sm1pwwhGDdZKcKrqiK8Y1mI= X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: E7D681C0006 X-Stat-Signature: j3gnp5chadrwsk9h9mr3ddapk7sg9hn6 X-Rspam-User: X-HE-Tag: 1766173481-816346 X-HE-Meta: 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 1pbrWWVr b3Bl0c7/kPIiWO12+CLeGLs6DnI8qUTa0EEPDibyWdL2mMkpt1JxXXX9NC2jkFMEH1xRDJeak1e5QdlwD3ArGKzmXkejwsJ6I0vAYwH7ltlN3/tO7cUpFxBsDRmw5Q94u5J34igW9CaII8D9RG3IyyCTj7Ie7QFPcsPMFpw/YA/MkVpUvlxTXejWNXZ4kY0Ke/I+gjfoJirc/fdqaygLc4zFHRha4gBrenE2erMA6xvy4OHLGFWRkMIn468pgdRubl/B69rf/oyIfs3j3YYBEFG0UCh6FBRWlonbNy+WgYWNd9rUaUDbmHbZKPi/D0wzUHZtw7xZZdhrIXf7HF+stUY8ETJa6DSPZO98Dl0FqD3EYtFgQMRH7qLh/G6mKcU5Sxn2H5Sngv/xB/lA= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Kairui Song Now swap cache is always used, multiple swap cache checks are no longer useful, remove them and reduce the code indention. No behavior change. Signed-off-by: Kairui Song --- mm/memory.c | 89 +++++++++++++++++++++++++++++-------------------------------- 1 file changed, 43 insertions(+), 46 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 9e391a283946..ca54009cd586 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4764,55 +4764,52 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) goto out_release; page = folio_file_page(folio, swp_offset(entry)); - if (swapcache) { - /* - * Make sure folio_free_swap() or swapoff did not release the - * swapcache from under us. The page pin, and pte_same test - * below, are not enough to exclude that. Even if it is still - * swapcache, we need to check that the page's swap has not - * changed. - */ - if (unlikely(!folio_matches_swap_entry(folio, entry))) - goto out_page; - - if (unlikely(PageHWPoison(page))) { - /* - * hwpoisoned dirty swapcache pages are kept for killing - * owner processes (which may be unknown at hwpoison time) - */ - ret = VM_FAULT_HWPOISON; - goto out_page; - } - - /* - * KSM sometimes has to copy on read faults, for example, if - * folio->index of non-ksm folios would be nonlinear inside the - * anon VMA -- the ksm flag is lost on actual swapout. - */ - folio = ksm_might_need_to_copy(folio, vma, vmf->address); - if (unlikely(!folio)) { - ret = VM_FAULT_OOM; - folio = swapcache; - goto out_page; - } else if (unlikely(folio == ERR_PTR(-EHWPOISON))) { - ret = VM_FAULT_HWPOISON; - folio = swapcache; - goto out_page; - } - if (folio != swapcache) - page = folio_page(folio, 0); + /* + * Make sure folio_free_swap() or swapoff did not release the + * swapcache from under us. The page pin, and pte_same test + * below, are not enough to exclude that. Even if it is still + * swapcache, we need to check that the page's swap has not + * changed. + */ + if (unlikely(!folio_matches_swap_entry(folio, entry))) + goto out_page; + if (unlikely(PageHWPoison(page))) { /* - * If we want to map a page that's in the swapcache writable, we - * have to detect via the refcount if we're really the exclusive - * owner. Try removing the extra reference from the local LRU - * caches if required. + * hwpoisoned dirty swapcache pages are kept for killing + * owner processes (which may be unknown at hwpoison time) */ - if ((vmf->flags & FAULT_FLAG_WRITE) && folio == swapcache && - !folio_test_ksm(folio) && !folio_test_lru(folio)) - lru_add_drain(); + ret = VM_FAULT_HWPOISON; + goto out_page; } + /* + * KSM sometimes has to copy on read faults, for example, if + * folio->index of non-ksm folios would be nonlinear inside the + * anon VMA -- the ksm flag is lost on actual swapout. + */ + folio = ksm_might_need_to_copy(folio, vma, vmf->address); + if (unlikely(!folio)) { + ret = VM_FAULT_OOM; + folio = swapcache; + goto out_page; + } else if (unlikely(folio == ERR_PTR(-EHWPOISON))) { + ret = VM_FAULT_HWPOISON; + folio = swapcache; + goto out_page; + } else if (folio != swapcache) + page = folio_page(folio, 0); + + /* + * If we want to map a page that's in the swapcache writable, we + * have to detect via the refcount if we're really the exclusive + * owner. Try removing the extra reference from the local LRU + * caches if required. + */ + if ((vmf->flags & FAULT_FLAG_WRITE) && + !folio_test_ksm(folio) && !folio_test_lru(folio)) + lru_add_drain(); + folio_throttle_swaprate(folio, GFP_KERNEL); /* @@ -5002,7 +4999,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) pte, pte, nr_pages); folio_unlock(folio); - if (folio != swapcache && swapcache) { + if (unlikely(folio != swapcache)) { /* * Hold the lock to avoid the swap entry to be reused * until we take the PT lock for the pte_same() check @@ -5040,7 +5037,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) folio_unlock(folio); out_release: folio_put(folio); - if (folio != swapcache && swapcache) { + if (folio != swapcache) { folio_unlock(swapcache); folio_put(swapcache); } -- 2.52.0