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charset="utf-8" From: Barry Song In the case of a swap-in, a new anonymous folio is not necessarily exclusive. This patch updates the rmap flags to allow a new anonymous folio to be treated as either exclusive or non-exclusive. To maintain the existing behavior, we always use EXCLUSIVE as the default setting. Suggested-by: David Hildenbrand Signed-off-by: Barry Song Tested-by: Shuai Yuan Acked-by: David Hildenbrand --- include/linux/rmap.h | 2 +- kernel/events/uprobes.c | 2 +- mm/huge_memory.c | 2 +- mm/khugepaged.c | 2 +- mm/memory.c | 10 +++++----- mm/migrate_device.c | 2 +- mm/rmap.c | 17 ++++++++++------- mm/swapfile.c | 2 +- mm/userfaultfd.c | 2 +- 9 files changed, 22 insertions(+), 19 deletions(-) diff --git a/include/linux/rmap.h b/include/linux/rmap.h index b1bbe237ea4c..23d336e5d502 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -244,7 +244,7 @@ void folio_add_anon_rmap_ptes(struct folio *, struct pa= ge *, int nr_pages, void folio_add_anon_rmap_pmd(struct folio *, struct page *, struct vm_area_struct *, unsigned long address, rmap_t flags); void folio_add_new_anon_rmap(struct folio *, struct vm_area_struct *, - unsigned long address); + unsigned long address, rmap_t flags); void folio_add_file_rmap_ptes(struct folio *, struct page *, int nr_pages, struct vm_area_struct *); #define folio_add_file_rmap_pte(folio, page, vma) \ diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 2c83ba776fc7..c20368aa33dd 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -181,7 +181,7 @@ static int __replace_page(struct vm_area_struct *vma, u= nsigned long addr, =20 if (new_page) { folio_get(new_folio); - folio_add_new_anon_rmap(new_folio, vma, addr); + folio_add_new_anon_rmap(new_folio, vma, addr, RMAP_EXCLUSIVE); folio_add_lru_vma(new_folio, vma); } else /* no new page, just dec_mm_counter for old_page */ diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 425374ae06ed..9e2357ab9b9a 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -973,7 +973,7 @@ static vm_fault_t __do_huge_pmd_anonymous_page(struct v= m_fault *vmf, =20 entry =3D mk_huge_pmd(page, vma->vm_page_prot); entry =3D maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); - folio_add_new_anon_rmap(folio, vma, haddr); + folio_add_new_anon_rmap(folio, vma, haddr, RMAP_EXCLUSIVE); folio_add_lru_vma(folio, vma); pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 774a97e6e2da..4d759a7487d0 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1213,7 +1213,7 @@ static int collapse_huge_page(struct mm_struct *mm, u= nsigned long address, =20 spin_lock(pmd_ptl); BUG_ON(!pmd_none(*pmd)); - folio_add_new_anon_rmap(folio, vma, address); + folio_add_new_anon_rmap(folio, vma, address, RMAP_EXCLUSIVE); folio_add_lru_vma(folio, vma); pgtable_trans_huge_deposit(mm, pmd, pgtable); set_pmd_at(mm, address, pmd, _pmd); diff --git a/mm/memory.c b/mm/memory.c index b7137d9c99a9..1f24ecdafe05 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -930,7 +930,7 @@ copy_present_page(struct vm_area_struct *dst_vma, struc= t vm_area_struct *src_vma *prealloc =3D NULL; copy_user_highpage(&new_folio->page, page, addr, src_vma); __folio_mark_uptodate(new_folio); - folio_add_new_anon_rmap(new_folio, dst_vma, addr); + folio_add_new_anon_rmap(new_folio, dst_vma, addr, RMAP_EXCLUSIVE); folio_add_lru_vma(new_folio, dst_vma); rss[MM_ANONPAGES]++; =20 @@ -3400,7 +3400,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) * some TLBs while the old PTE remains in others. */ ptep_clear_flush(vma, vmf->address, vmf->pte); - folio_add_new_anon_rmap(new_folio, vma, vmf->address); + folio_add_new_anon_rmap(new_folio, vma, vmf->address, RMAP_EXCLUSIVE); folio_add_lru_vma(new_folio, vma); BUG_ON(unshare && pte_write(entry)); set_pte_at(mm, vmf->address, vmf->pte, entry); @@ -4337,7 +4337,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) =20 /* ksm created a completely new copy */ if (unlikely(folio !=3D swapcache && swapcache)) { - folio_add_new_anon_rmap(folio, vma, address); + folio_add_new_anon_rmap(folio, vma, address, RMAP_EXCLUSIVE); folio_add_lru_vma(folio, vma); } else { folio_add_anon_rmap_ptes(folio, page, nr_pages, vma, address, @@ -4592,7 +4592,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault *= vmf) #ifdef CONFIG_TRANSPARENT_HUGEPAGE count_mthp_stat(folio_order(folio), MTHP_STAT_ANON_FAULT_ALLOC); #endif - folio_add_new_anon_rmap(folio, vma, addr); + folio_add_new_anon_rmap(folio, vma, addr, RMAP_EXCLUSIVE); folio_add_lru_vma(folio, vma); setpte: if (vmf_orig_pte_uffd_wp(vmf)) @@ -4790,7 +4790,7 @@ void set_pte_range(struct vm_fault *vmf, struct folio= *folio, /* copy-on-write page */ if (write && !(vma->vm_flags & VM_SHARED)) { VM_BUG_ON_FOLIO(nr !=3D 1, folio); - folio_add_new_anon_rmap(folio, vma, addr); + folio_add_new_anon_rmap(folio, vma, addr, RMAP_EXCLUSIVE); folio_add_lru_vma(folio, vma); } else { folio_add_file_rmap_ptes(folio, page, nr, vma); diff --git a/mm/migrate_device.c b/mm/migrate_device.c index 051d0a3ccbee..6d66dc1c6ffa 100644 --- a/mm/migrate_device.c +++ b/mm/migrate_device.c @@ -658,7 +658,7 @@ static void migrate_vma_insert_page(struct migrate_vma = *migrate, goto unlock_abort; =20 inc_mm_counter(mm, MM_ANONPAGES); - folio_add_new_anon_rmap(folio, vma, addr); + folio_add_new_anon_rmap(folio, vma, addr, RMAP_EXCLUSIVE); if (!folio_is_zone_device(folio)) folio_add_lru_vma(folio, vma); folio_get(folio); diff --git a/mm/rmap.c b/mm/rmap.c index a3c99ac63155..2b19bb92eda5 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1406,25 +1406,26 @@ void folio_add_anon_rmap_pmd(struct folio *folio, s= truct page *page, * This means the inc-and-test can be bypassed. * The folio does not have to be locked. * - * If the folio is pmd-mappable, it is accounted as a THP. As the folio - * is new, it's assumed to be mapped exclusively by a single process. + * If the folio is pmd-mappable, it is accounted as a THP. */ void folio_add_new_anon_rmap(struct folio *folio, struct vm_area_struct *v= ma, - unsigned long address) + unsigned long address, rmap_t flags) { int nr =3D folio_nr_pages(folio); int nr_pmdmapped =3D 0; + bool exclusive =3D flags & RMAP_EXCLUSIVE; =20 VM_WARN_ON_FOLIO(folio_test_hugetlb(folio), folio); VM_BUG_ON_VMA(address < vma->vm_start || address + (nr << PAGE_SHIFT) > vma->vm_end, vma); __folio_set_swapbacked(folio); - __folio_set_anon(folio, vma, address, true); + __folio_set_anon(folio, vma, address, exclusive); =20 if (likely(!folio_test_large(folio))) { /* increment count (starts at -1) */ atomic_set(&folio->_mapcount, 0); - SetPageAnonExclusive(&folio->page); + if (exclusive) + SetPageAnonExclusive(&folio->page); } else if (!folio_test_pmd_mappable(folio)) { int i; =20 @@ -1433,7 +1434,8 @@ void folio_add_new_anon_rmap(struct folio *folio, str= uct vm_area_struct *vma, =20 /* increment count (starts at -1) */ atomic_set(&page->_mapcount, 0); - SetPageAnonExclusive(page); + if (exclusive) + SetPageAnonExclusive(page); } =20 /* increment count (starts at -1) */ @@ -1445,7 +1447,8 @@ void folio_add_new_anon_rmap(struct folio *folio, str= uct vm_area_struct *vma, /* increment count (starts at -1) */ atomic_set(&folio->_large_mapcount, 0); atomic_set(&folio->_nr_pages_mapped, ENTIRELY_MAPPED); - SetPageAnonExclusive(&folio->page); + if (exclusive) + SetPageAnonExclusive(&folio->page); nr_pmdmapped =3D nr; } =20 diff --git a/mm/swapfile.c b/mm/swapfile.c index 9c6d8e557c0f..ae1d2700f6a3 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1911,7 +1911,7 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_= t *pmd, =20 folio_add_anon_rmap_pte(folio, page, vma, addr, rmap_flags); } else { /* ksm created a completely new copy */ - folio_add_new_anon_rmap(folio, vma, addr); + folio_add_new_anon_rmap(folio, vma, addr, RMAP_EXCLUSIVE); folio_add_lru_vma(folio, vma); } new_pte =3D pte_mkold(mk_pte(page, vma->vm_page_prot)); diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 5e7f2801698a..8dedaec00486 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -216,7 +216,7 @@ int mfill_atomic_install_pte(pmd_t *dst_pmd, folio_add_lru(folio); 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Mon, 17 Jun 2024 16:12:06 -0700 (PDT) From: Barry Song <21cnbao@gmail.com> To: akpm@linux-foundation.org, david@redhat.com, linux-mm@kvack.org Cc: baolin.wang@linux.alibaba.com, chrisl@kernel.org, linux-kernel@vger.kernel.org, mhocko@suse.com, ryan.roberts@arm.com, shy828301@gmail.com, surenb@google.com, v-songbaohua@oppo.com, willy@infradead.org, ying.huang@intel.com, yosryahmed@google.com, yuzhao@google.com, Shuai Yuan Subject: [PATCH v2 2/3] mm: use folio_add_new_anon_rmap() if folio_test_anon(folio)==false Date: Tue, 18 Jun 2024 11:11:36 +1200 Message-Id: <20240617231137.80726-3-21cnbao@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240617231137.80726-1-21cnbao@gmail.com> References: <20240617231137.80726-1-21cnbao@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable From: Barry Song For the !folio_test_anon(folio) case, we can now invoke folio_add_new_anon_= rmap() with the rmap flags set to either EXCLUSIVE or non-EXCLUSIVE. This action w= ill suppress the VM_WARN_ON_FOLIO check within __folio_add_anon_rmap() while in= itiating the process of bringing up mTHP swapin. static __always_inline void __folio_add_anon_rmap(struct folio *folio, struct page *page, int nr_pages, struct vm_area_struct *vm= a, unsigned long address, rmap_t flags, enum rmap_level level) { ... if (unlikely(!folio_test_anon(folio))) { VM_WARN_ON_FOLIO(folio_test_large(folio) && level !=3D RMAP_LEVEL_PMD, folio); } ... } It also improves the code=E2=80=99s readability. Currently, all new anonymo= us folios calling folio_add_anon_rmap_ptes() are order-0. This ensures that new folios cannot be partially exclusive; they are either entirely exclusive or entirely shared. Suggested-by: David Hildenbrand Signed-off-by: Barry Song Tested-by: Shuai Yuan Acked-by: David Hildenbrand --- mm/memory.c | 8 ++++++++ mm/swapfile.c | 13 +++++++++++-- 2 files changed, 19 insertions(+), 2 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 1f24ecdafe05..620654c13b2f 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4339,6 +4339,14 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) if (unlikely(folio !=3D swapcache && swapcache)) { folio_add_new_anon_rmap(folio, vma, address, RMAP_EXCLUSIVE); folio_add_lru_vma(folio, vma); + } else if (!folio_test_anon(folio)) { + /* + * We currently only expect small !anon folios, for which we now + * that they are either fully exclusive or fully shared. If we + * ever get large folios here, we have to be careful. + */ + VM_WARN_ON_ONCE(folio_test_large(folio)); + folio_add_new_anon_rmap(folio, vma, address, rmap_flags); } else { folio_add_anon_rmap_ptes(folio, page, nr_pages, vma, address, rmap_flags); diff --git a/mm/swapfile.c b/mm/swapfile.c index ae1d2700f6a3..69efa1a57087 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1908,8 +1908,17 @@ static int unuse_pte(struct vm_area_struct *vma, pmd= _t *pmd, VM_BUG_ON_FOLIO(folio_test_writeback(folio), folio); if (pte_swp_exclusive(old_pte)) rmap_flags |=3D RMAP_EXCLUSIVE; - - folio_add_anon_rmap_pte(folio, page, vma, addr, rmap_flags); + /* + * We currently only expect small !anon folios, for which we now that + * they are either fully exclusive or fully shared. 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Mon, 17 Jun 2024 16:12:12 -0700 (PDT) From: Barry Song <21cnbao@gmail.com> To: akpm@linux-foundation.org, david@redhat.com, linux-mm@kvack.org Cc: baolin.wang@linux.alibaba.com, chrisl@kernel.org, linux-kernel@vger.kernel.org, mhocko@suse.com, ryan.roberts@arm.com, shy828301@gmail.com, surenb@google.com, v-songbaohua@oppo.com, willy@infradead.org, ying.huang@intel.com, yosryahmed@google.com, yuzhao@google.com, Shuai Yuan Subject: [PATCH v2 3/3] mm: remove folio_test_anon(folio)==false path in __folio_add_anon_rmap() Date: Tue, 18 Jun 2024 11:11:37 +1200 Message-Id: <20240617231137.80726-4-21cnbao@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240617231137.80726-1-21cnbao@gmail.com> References: <20240617231137.80726-1-21cnbao@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Barry Song The folio_test_anon(folio)=3D=3Dfalse cases has been relocated to folio_add_new_anon_rmap(). Additionally, four other callers consistently pass anonymous folios. stack 1: remove_migration_pmd -> folio_add_anon_rmap_pmd -> __folio_add_anon_rmap stack 2: __split_huge_pmd_locked -> folio_add_anon_rmap_ptes -> __folio_add_anon_rmap stack 3: remove_migration_pmd -> folio_add_anon_rmap_pmd -> __folio_add_anon_rmap (RMAP_LEVEL_PMD) stack 4: try_to_merge_one_page -> replace_page -> folio_add_anon_rmap_pte -> __folio_add_anon_rmap __folio_add_anon_rmap() only needs to handle the cases folio_test_anon(folio)=3D=3Dtrue now. We can remove the !folio_test_anon(folio)) path within __folio_add_anon_rmap() now. Suggested-by: David Hildenbrand Signed-off-by: Barry Song Tested-by: Shuai Yuan Acked-by: David Hildenbrand --- mm/rmap.c | 17 +++-------------- 1 file changed, 3 insertions(+), 14 deletions(-) diff --git a/mm/rmap.c b/mm/rmap.c index 2b19bb92eda5..ddcdda752982 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1297,23 +1297,12 @@ static __always_inline void __folio_add_anon_rmap(s= truct folio *folio, { int i, nr, nr_pmdmapped =3D 0; =20 + VM_WARN_ON_FOLIO(!folio_test_anon(folio), folio); + nr =3D __folio_add_rmap(folio, page, nr_pages, level, &nr_pmdmapped); =20 - if (unlikely(!folio_test_anon(folio))) { - VM_WARN_ON_FOLIO(!folio_test_locked(folio), folio); - /* - * For a PTE-mapped large folio, we only know that the single - * PTE is exclusive. Further, __folio_set_anon() might not get - * folio->index right when not given the address of the head - * page. - */ - VM_WARN_ON_FOLIO(folio_test_large(folio) && - level !=3D RMAP_LEVEL_PMD, folio); - __folio_set_anon(folio, vma, address, - !!(flags & RMAP_EXCLUSIVE)); - } else if (likely(!folio_test_ksm(folio))) { + if (likely(!folio_test_ksm(folio))) __page_check_anon_rmap(folio, page, vma, address); - } =20 __folio_mod_stat(folio, nr, nr_pmdmapped); =20 --=20 2.34.1