From patchwork Wed May 1 04:27:00 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lance Yang X-Patchwork-Id: 13650208 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 067CDC4345F for ; Wed, 1 May 2024 04:27:29 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 90CB06B008A; Wed, 1 May 2024 00:27:28 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8BD096B008C; Wed, 1 May 2024 00:27:28 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 737AE6B0092; Wed, 1 May 2024 00:27:28 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 540B56B008A for ; Wed, 1 May 2024 00:27:28 -0400 (EDT) Received: from smtpin22.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id C89DFA16A5 for ; Wed, 1 May 2024 04:27:27 +0000 (UTC) X-FDA: 82068542934.22.130B7C3 Received: from mail-pf1-f173.google.com (mail-pf1-f173.google.com [209.85.210.173]) by imf19.hostedemail.com (Postfix) with ESMTP id 05CC81A000B for ; Wed, 1 May 2024 04:27:25 +0000 (UTC) Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b="eC/5nZlL"; spf=pass (imf19.hostedemail.com: domain of ioworker0@gmail.com designates 209.85.210.173 as permitted sender) smtp.mailfrom=ioworker0@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1714537646; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=hOzQapCM9/nhQFCiXcuQFHHgx8BSo7e2vP87qJAgbT0=; b=ZYT9dQsHrAeHhN39/AUAnBHyJ+R9fSrGlgxQ8btfahVfOOSxrLHZzE3kgwyLGeTuGrRSvv cdwx2EW3D3f+W/M4VNr87HNsUOyUtciZ6Gnuw7EnLFaIoeovvSTD1ySx1r/A8XVqybhqLB 00oxgs3jTKVUXAiYVKc3tw4drV765fI= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b="eC/5nZlL"; spf=pass (imf19.hostedemail.com: domain of ioworker0@gmail.com designates 209.85.210.173 as permitted sender) smtp.mailfrom=ioworker0@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1714537646; a=rsa-sha256; cv=none; b=DNMHwqDDOlY/Eyd2hJlScxL9OtxUx86eQ3GfCnuGlqfGDmv5U8NuE9L/Xy+uxqoJETVKh7 eWVfVxo+iKFpeihFEiTrb6VcQ+M3/M8e/DogXV1++8xC9w7zdiHiBz/W+gyC/VnQDonbT+ gjwVrE4chjGn/45/GQi5hNCMLjSdfsE= Received: by mail-pf1-f173.google.com with SMTP id d2e1a72fcca58-6effe9c852eso5767910b3a.3 for ; Tue, 30 Apr 2024 21:27:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1714537645; x=1715142445; darn=kvack.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=hOzQapCM9/nhQFCiXcuQFHHgx8BSo7e2vP87qJAgbT0=; b=eC/5nZlLP5acP1YfnY0MUc1mgioLhu+OLi5KMLolAr/eKTOJPkapcIO/1azaFIiNrC J3PaL46p09BxBIjjFjaw/taYu1FEadWrMWBYN8OIdQktWQ3eYj0vQomoq3RKI4JEUmgG WPwJGDzMSLLdca/NVamT41u3a5Grfr4WftqZjCEIrF8nCXKFsjO0hmRztx3fsaPDZPzf i/BHvfZIacxZ/LfPclv1pTLGLSL0EHXCDujxTW3cdIKnWaK90dz17kyGBIsxHXnWzBhv mPHY/bSxKHzeLJKMtm0jS8gqZOtrAT6aHc0fZf6jveHMx5JSdgnZcJ7oZkbh1N8nSZ7X Iqyw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1714537645; x=1715142445; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=hOzQapCM9/nhQFCiXcuQFHHgx8BSo7e2vP87qJAgbT0=; b=QNdtrgt6bSoTpmZT7u1vrqbg2OxnkY3nJcWVjOqvTpel0fEFQIMGyDenltx3mW+Zea byaFKoK72iv7+1D7S39LX0S1w7McLFOCE1CCTa5JGZPe9HKzK3/wFey/u+ATOM1Uaqee dSDfju9pE635BgRPD9AzfcNwpXHE4Uthw/GYjcaOCnciKiMNMMqtaykWwaavW5uCOqbA Q9bxqeBWYzFteXsaIoYAjZXujLywO2mgnpvV/cBy4uCuVMvenSuZli5eIzUo2PpaKbY/ D/D+kVzIP9p5dR2tn+he2aWuUqbeoK+C6v+5nSniF9E/+4gX97vfB6MNJvW7lmQ4e42P TT9w== X-Forwarded-Encrypted: i=1; AJvYcCV0Hj8eTx6sRFmgSzxU1il4Us8gTwKeAzKR0Uen/Kboz88CQpHIzFUG5+kzTpqkM60vLH81KuHg8OT1eCHVzffmksI= X-Gm-Message-State: AOJu0YyJ85DSZHvhdnxVEQ+psKszzLm0U6jmTAkQ9FP1igUokcMmTlV4 oRbggDmZ7lzKjvPq4G327hctXtSMMIy7E1IMPO8KKlUj6+MFOpbP X-Google-Smtp-Source: AGHT+IExH8/mQKcC+a0yuiE7nJbe/y3Zn478CUKsgvKf8sffmUuOcVVFi/q1aIYi5BB/0pju90QCCg== X-Received: by 2002:a05:6a00:2345:b0:6ed:d8d2:503d with SMTP id j5-20020a056a00234500b006edd8d2503dmr2150218pfj.20.1714537644912; Tue, 30 Apr 2024 21:27:24 -0700 (PDT) Received: from LancedeMBP.lan ([112.10.225.242]) by smtp.gmail.com with ESMTPSA id m15-20020a656a0f000000b005dc4806ad7dsm19165970pgu.40.2024.04.30.21.27.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Apr 2024 21:27:24 -0700 (PDT) From: Lance Yang To: akpm@linux-foundation.org Cc: willy@infradead.org, sj@kernel.org, maskray@google.com, ziy@nvidia.com, ryan.roberts@arm.com, david@redhat.com, 21cnbao@gmail.com, mhocko@suse.com, fengwei.yin@intel.com, zokeefe@google.com, shy828301@gmail.com, xiehuan09@gmail.com, libang.li@antgroup.com, wangkefeng.wang@huawei.com, songmuchun@bytedance.com, peterx@redhat.com, minchan@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Lance Yang Subject: [PATCH v4 3/3] mm/vmscan: avoid split lazyfree THP during shrink_folio_list() Date: Wed, 1 May 2024 12:27:00 +0800 Message-Id: <20240501042700.83974-4-ioworker0@gmail.com> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20240501042700.83974-1-ioworker0@gmail.com> References: <20240501042700.83974-1-ioworker0@gmail.com> MIME-Version: 1.0 X-Rspamd-Queue-Id: 05CC81A000B X-Rspam-User: X-Rspamd-Server: rspam04 X-Stat-Signature: tqtue8wdumt8xg86horfi6i35ercahdz X-HE-Tag: 1714537645-90837 X-HE-Meta: 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 zrR9BFt+ 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 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: When the user no longer requires the pages, they would use madvise(MADV_FREE) to mark the pages as lazy free. Subsequently, they typically would not re-write to that memory again. During memory reclaim, if we detect that the large folio and its PMD are both still marked as clean and there are no unexpected references (such as GUP), so we can just discard the memory lazily, improving the efficiency of memory reclamation in this case. On an Intel i5 CPU, reclaiming 1GiB of lazyfree THPs using mem_cgroup_force_empty() results in the following runtimes in seconds (shorter is better): -------------------------------------------- | Old | New | Change | -------------------------------------------- | 0.683426 | 0.049197 | -92.80% | -------------------------------------------- Suggested-by: Zi Yan Suggested-by: David Hildenbrand Signed-off-by: Lance Yang --- include/linux/huge_mm.h | 9 +++++ mm/huge_memory.c | 73 +++++++++++++++++++++++++++++++++++++++++ mm/rmap.c | 3 ++ 3 files changed, 85 insertions(+) diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index 38c4b5537715..017cee864080 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -411,6 +411,8 @@ static inline bool thp_migration_supported(void) void split_huge_pmd_locked(struct vm_area_struct *vma, unsigned long address, pmd_t *pmd, bool freeze, struct folio *folio); +bool unmap_huge_pmd_locked(struct vm_area_struct *vma, unsigned long addr, + pmd_t *pmdp, struct folio *folio); static inline void align_huge_pmd_range(struct vm_area_struct *vma, unsigned long *start, @@ -492,6 +494,13 @@ static inline void align_huge_pmd_range(struct vm_area_struct *vma, unsigned long *start, unsigned long *end) {} +static inline bool unmap_huge_pmd_locked(struct vm_area_struct *vma, + unsigned long addr, pmd_t *pmdp, + struct folio *folio) +{ + return false; +} + #define split_huge_pud(__vma, __pmd, __address) \ do { } while (0) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 145505a1dd05..90fdef847a88 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2690,6 +2690,79 @@ static void unmap_folio(struct folio *folio) try_to_unmap_flush(); } +static bool __discard_trans_pmd_locked(struct vm_area_struct *vma, + unsigned long addr, pmd_t *pmdp, + struct folio *folio) +{ + struct mm_struct *mm = vma->vm_mm; + int ref_count, map_count; + pmd_t orig_pmd = *pmdp; + struct mmu_gather tlb; + struct page *page; + + if (pmd_dirty(orig_pmd) || folio_test_dirty(folio)) + return false; + if (unlikely(!pmd_present(orig_pmd) || !pmd_trans_huge(orig_pmd))) + return false; + + page = pmd_page(orig_pmd); + if (unlikely(page_folio(page) != folio)) + return false; + + tlb_gather_mmu(&tlb, mm); + orig_pmd = pmdp_huge_get_and_clear(mm, addr, pmdp); + tlb_remove_pmd_tlb_entry(&tlb, pmdp, addr); + + /* + * Syncing against concurrent GUP-fast: + * - clear PMD; barrier; read refcount + * - inc refcount; barrier; read PMD + */ + smp_mb(); + + ref_count = folio_ref_count(folio); + map_count = folio_mapcount(folio); + + /* + * Order reads for folio refcount and dirty flag + * (see comments in __remove_mapping()). + */ + smp_rmb(); + + /* + * If the PMD or folio is redirtied at this point, or if there are + * unexpected references, we will give up to discard this folio + * and remap it. + * + * The only folio refs must be one from isolation plus the rmap(s). + */ + if (ref_count != map_count + 1 || folio_test_dirty(folio) || + pmd_dirty(orig_pmd)) { + set_pmd_at(mm, addr, pmdp, orig_pmd); + return false; + } + + folio_remove_rmap_pmd(folio, page, vma); + zap_deposited_table(mm, pmdp); + add_mm_counter(mm, MM_ANONPAGES, -HPAGE_PMD_NR); + folio_put(folio); + + return true; +} + +bool unmap_huge_pmd_locked(struct vm_area_struct *vma, unsigned long addr, + pmd_t *pmdp, struct folio *folio) +{ + VM_WARN_ON_FOLIO(!folio_test_pmd_mappable(folio), folio); + VM_WARN_ON_FOLIO(!folio_test_locked(folio), folio); + VM_WARN_ON_ONCE(!IS_ALIGNED(addr, HPAGE_PMD_SIZE)); + + if (folio_test_anon(folio) && !folio_test_swapbacked(folio)) + return __discard_trans_pmd_locked(vma, addr, pmdp, folio); + + return false; +} + static void remap_page(struct folio *folio, unsigned long nr) { int i = 0; diff --git a/mm/rmap.c b/mm/rmap.c index 432601154583..1d3d30cb752c 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1675,6 +1675,9 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, } if (!pvmw.pte && (flags & TTU_SPLIT_HUGE_PMD)) { + if (unmap_huge_pmd_locked(vma, range.start, pvmw.pmd, + folio)) + goto walk_done; /* * We temporarily have to drop the PTL and start once * again from that now-PTE-mapped page table.