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AJvYcCWvsAGHLd0XkXrrmRO4MK+ix4PM/QzLID85bGa8+65Oz1K0layk4Pkul+/gkXvwnk0grQt9kDusmUOxI6t5K8TDPOg= X-Gm-Message-State: AOJu0YyRejAm8Jg2Onxh3mdrjtAuSWAYUI5f3ID9LlBeWKDAEtJ/6TRe sH0RMgQfS53o9f8XcBnGC3gqP9ZGu+sfPVzqo39Poh8Jk/Ckvpas X-Google-Smtp-Source: AGHT+IEIpuabuqonhYE79on+MmpCBMiXOyD1MynjuJ+zgMt6P3Xc90pOg4tUdHHFiZ9X3J2Nmmenng== X-Received: by 2002:a05:6a00:4f8f:b0:6ea:d114:5ea1 with SMTP id d2e1a72fcca58-6f4e02cae54mr13273237b3a.17.1715586480465; Mon, 13 May 2024 00:48:00 -0700 (PDT) Received: from LancedeMBP.lan.lan ([2403:2c80:6::304b]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-6f4d2a66621sm7008967b3a.13.2024.05.13.00.47.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 13 May 2024 00:48:00 -0700 (PDT) From: Lance Yang To: akpm@linux-foundation.org Cc: willy@infradead.org, sj@kernel.org, baolin.wang@linux.alibaba.com, 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 RESEND v5 2/4] mm/rmap: integrate PMD-mapped folio splitting into pagewalk loop Date: Mon, 13 May 2024 15:47:10 +0800 Message-Id: <20240513074712.7608-3-ioworker0@gmail.com> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20240513074712.7608-1-ioworker0@gmail.com> References: <20240513074712.7608-1-ioworker0@gmail.com> MIME-Version: 1.0 X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: A1484180007 X-Rspam-User: X-Stat-Signature: 6fjyi3srxn61rpof9cqgs9zp3jmrea7s X-HE-Tag: 1715586481-830930 X-HE-Meta: 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 QKL6dO2J qC7nnga40/caZ5OGm+rjLef7vZGhEeH9bX1h7CFO5hep686g7Tol+g38TofNi/Z6KKwmzJkKF+E9A3UfUlRNyUp8iL1wA/E4NpDhFhZh397SI8+7Qwq3SErpkvlzFjXu/nIXKjbQTJ2qi8C6Z0yu2DToV2gsq6taODZqNcun0UK0SW16/Q/veow3+ADWeraoHRyWLMeWlepPWYaIBS2bzJh7v7YAtmTFrm0keCcAp6ChJVKPSLCRKP6QL+da36zQrdrmkVUnyT0XY2JgDAeNPwxiF991GPeVlSEWQsIqHtnLVonNlvF2jijab9SuPpibzAz4baP5/hY+hHBIVWiK+YQGQ5quZarQw2eh2BomBo9JU0dVgqU6bSgSTmhOaJLPacwfAAkm0diPhhD5wYiHb9zzSgasvbdcUj6/yWwdxYgHpsjGFLwEttkWjmJc20S8ON21HcoYlL4BZMfOP3bMOEEGHRH1FaCrVYQ7j 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: In preparation for supporting try_to_unmap_one() to unmap PMD-mapped folios, start the pagewalk first, then call split_huge_pmd_address() to split the folio. Suggested-by: David Hildenbrand Signed-off-by: Lance Yang --- include/linux/huge_mm.h | 6 ++++++ mm/huge_memory.c | 42 +++++++++++++++++++++-------------------- mm/rmap.c | 23 ++++++++++++++++------ 3 files changed, 45 insertions(+), 26 deletions(-) diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index c8d3ec116e29..9fcb0b0b6ed1 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -409,6 +409,9 @@ static inline bool thp_migration_supported(void) return IS_ENABLED(CONFIG_ARCH_ENABLE_THP_MIGRATION); } +void split_huge_pmd_locked(struct vm_area_struct *vma, unsigned long address, + pmd_t *pmd, bool freeze, struct folio *folio); + #else /* CONFIG_TRANSPARENT_HUGEPAGE */ static inline bool folio_test_pmd_mappable(struct folio *folio) @@ -471,6 +474,9 @@ static inline void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, unsigned long address, bool freeze, struct folio *folio) {} static inline void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, bool freeze, struct folio *folio) {} +static inline void split_huge_pmd_locked(struct vm_area_struct *vma, + unsigned long address, pmd_t *pmd, + bool freeze, struct folio *folio) {} #define split_huge_pud(__vma, __pmd, __address) \ do { } while (0) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 317de2afd371..425272c6c50b 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2581,6 +2581,27 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, pmd_populate(mm, pmd, pgtable); } +void split_huge_pmd_locked(struct vm_area_struct *vma, unsigned long address, + pmd_t *pmd, bool freeze, struct folio *folio) +{ + VM_WARN_ON_ONCE(folio && !folio_test_pmd_mappable(folio)); + VM_WARN_ON_ONCE(!IS_ALIGNED(address, HPAGE_PMD_SIZE)); + VM_WARN_ON_ONCE(folio && !folio_test_locked(folio)); + VM_BUG_ON(freeze && !folio); + + /* + * When the caller requests to set up a migration entry, we + * require a folio to check the PMD against. Otherwise, there + * is a risk of replacing the wrong folio. + */ + if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd) || + is_pmd_migration_entry(*pmd)) { + if (folio && folio != pmd_folio(*pmd)) + return; + __split_huge_pmd_locked(vma, pmd, address, freeze); + } +} + void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, unsigned long address, bool freeze, struct folio *folio) { @@ -2592,26 +2613,7 @@ void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE); mmu_notifier_invalidate_range_start(&range); ptl = pmd_lock(vma->vm_mm, pmd); - - /* - * If caller asks to setup a migration entry, we need a folio to check - * pmd against. Otherwise we can end up replacing wrong folio. - */ - VM_BUG_ON(freeze && !folio); - VM_WARN_ON_ONCE(folio && !folio_test_locked(folio)); - - if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd) || - is_pmd_migration_entry(*pmd)) { - /* - * It's safe to call pmd_page when folio is set because it's - * guaranteed that pmd is present. - */ - if (folio && folio != pmd_folio(*pmd)) - goto out; - __split_huge_pmd_locked(vma, pmd, range.start, freeze); - } - -out: + split_huge_pmd_locked(vma, range.start, pmd, freeze, folio); spin_unlock(ptl); mmu_notifier_invalidate_range_end(&range); } diff --git a/mm/rmap.c b/mm/rmap.c index ddffa30c79fb..4c4d14325f2e 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1640,9 +1640,6 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, if (flags & TTU_SYNC) pvmw.flags = PVMW_SYNC; - if (flags & TTU_SPLIT_HUGE_PMD) - split_huge_pmd_address(vma, address, false, folio); - /* * For THP, we have to assume the worse case ie pmd for invalidation. * For hugetlb, it could be much worse if we need to do pud @@ -1668,9 +1665,6 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, mmu_notifier_invalidate_range_start(&range); while (page_vma_mapped_walk(&pvmw)) { - /* Unexpected PMD-mapped THP? */ - VM_BUG_ON_FOLIO(!pvmw.pte, folio); - /* * If the folio is in an mlock()d vma, we must not swap it out. */ @@ -1682,6 +1676,23 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, goto walk_done_err; } + if (!pvmw.pte && (flags & TTU_SPLIT_HUGE_PMD)) { + /* + * We temporarily have to drop the PTL and start once + * again from that now-PTE-mapped page table. + */ + split_huge_pmd_locked(vma, range.start, pvmw.pmd, false, + folio); + pvmw.pmd = NULL; + spin_unlock(pvmw.ptl); + pvmw.ptl = NULL; + flags &= ~TTU_SPLIT_HUGE_PMD; + continue; + } + + /* Unexpected PMD-mapped THP? */ + VM_BUG_ON_FOLIO(!pvmw.pte, folio); + pfn = pte_pfn(ptep_get(pvmw.pte)); subpage = folio_page(folio, pfn - folio_pfn(folio)); address = pvmw.address;