From: Suren Baghdasaryan <surenb@google.com>
To: akpm@linux-foundation.org
Cc: michel@lespinasse.org, jglisse@google.com, mhocko@suse.com,
vbabka@suse.cz, hannes@cmpxchg.org, mgorman@techsingularity.net,
dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com,
peterz@infradead.org, ldufour@linux.ibm.com, paulmck@kernel.org,
mingo@redhat.com, will@kernel.org, luto@kernel.org,
songliubraving@fb.com, peterx@redhat.com, david@redhat.com,
dhowells@redhat.com, hughd@google.com, bigeasy@linutronix.de,
kent.overstreet@linux.dev, punit.agrawal@bytedance.com,
lstoakes@gmail.com, peterjung1337@gmail.com, rientjes@google.com,
chriscli@google.com, axelrasmussen@google.com, joelaf@google.com,
minchan@google.com, rppt@kernel.org, jannh@google.com,
shakeelb@google.com, tatashin@google.com, edumazet@google.com,
gthelen@google.com, gurua@google.com, arjunroy@google.com,
soheil@google.com, leewalsh@google.com, posk@google.com,
michalechner92@googlemail.com, linux-mm@kvack.org,
linux-arm-kernel@lists.infradead.org,
linuxppc-dev@lists.ozlabs.org, x86@kernel.org,
linux-kernel@vger.kernel.org, kernel-team@android.com,
Suren Baghdasaryan <surenb@google.com>
Subject: [PATCH v3 15/35] mm/khugepaged: write-lock VMA while collapsing a huge page
Date: Wed, 15 Feb 2023 21:17:30 -0800 [thread overview]
Message-ID: <20230216051750.3125598-16-surenb@google.com> (raw)
In-Reply-To: <20230216051750.3125598-1-surenb@google.com>
Protect VMA from concurrent page fault handler while collapsing a huge
page. Page fault handler needs a stable PMD to use PTL and relies on
per-VMA lock to prevent concurrent PMD changes. pmdp_collapse_flush(),
set_huge_pmd() and collapse_and_free_pmd() can modify a PMD, which will
not be detected by a page fault handler without proper locking.
Before this patch, page tables can be walked under any one of the
mmap_lock, the mapping lock, and the anon_vma lock; so when khugepaged
unlinks and frees page tables, it must ensure that all of those either
are locked or don't exist. This patch adds a fourth lock under which
page tables can be traversed, and so khugepaged must also lock out that
one.
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
---
mm/khugepaged.c | 5 +++++
mm/rmap.c | 31 ++++++++++++++++---------------
2 files changed, 21 insertions(+), 15 deletions(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 8dbc39896811..d9376acf1fbe 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1140,6 +1140,7 @@ static int collapse_huge_page(struct mm_struct *mm, unsigned long address,
if (result != SCAN_SUCCEED)
goto out_up_write;
+ vma_start_write(vma);
anon_vma_lock_write(vma->anon_vma);
mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, mm, address,
@@ -1607,6 +1608,9 @@ int collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr,
goto drop_hpage;
}
+ /* Lock the vma before taking i_mmap and page table locks */
+ vma_start_write(vma);
+
/*
* We need to lock the mapping so that from here on, only GUP-fast and
* hardware page walks can access the parts of the page tables that
@@ -1812,6 +1816,7 @@ static int retract_page_tables(struct address_space *mapping, pgoff_t pgoff,
result = SCAN_PTE_UFFD_WP;
goto unlock_next;
}
+ vma_start_write(vma);
collapse_and_free_pmd(mm, vma, addr, pmd);
if (!cc->is_khugepaged && is_target)
result = set_huge_pmd(vma, addr, pmd, hpage);
diff --git a/mm/rmap.c b/mm/rmap.c
index 15ae24585fc4..8e1a2ad9ca53 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -25,21 +25,22 @@
* mapping->invalidate_lock (in filemap_fault)
* page->flags PG_locked (lock_page)
* hugetlbfs_i_mmap_rwsem_key (in huge_pmd_share, see hugetlbfs below)
- * mapping->i_mmap_rwsem
- * anon_vma->rwsem
- * mm->page_table_lock or pte_lock
- * swap_lock (in swap_duplicate, swap_info_get)
- * mmlist_lock (in mmput, drain_mmlist and others)
- * mapping->private_lock (in block_dirty_folio)
- * folio_lock_memcg move_lock (in block_dirty_folio)
- * i_pages lock (widely used)
- * lruvec->lru_lock (in folio_lruvec_lock_irq)
- * inode->i_lock (in set_page_dirty's __mark_inode_dirty)
- * bdi.wb->list_lock (in set_page_dirty's __mark_inode_dirty)
- * sb_lock (within inode_lock in fs/fs-writeback.c)
- * i_pages lock (widely used, in set_page_dirty,
- * in arch-dependent flush_dcache_mmap_lock,
- * within bdi.wb->list_lock in __sync_single_inode)
+ * vma_start_write
+ * mapping->i_mmap_rwsem
+ * anon_vma->rwsem
+ * mm->page_table_lock or pte_lock
+ * swap_lock (in swap_duplicate, swap_info_get)
+ * mmlist_lock (in mmput, drain_mmlist and others)
+ * mapping->private_lock (in block_dirty_folio)
+ * folio_lock_memcg move_lock (in block_dirty_folio)
+ * i_pages lock (widely used)
+ * lruvec->lru_lock (in folio_lruvec_lock_irq)
+ * inode->i_lock (in set_page_dirty's __mark_inode_dirty)
+ * bdi.wb->list_lock (in set_page_dirty's __mark_inode_dirty)
+ * sb_lock (within inode_lock in fs/fs-writeback.c)
+ * i_pages lock (widely used, in set_page_dirty,
+ * in arch-dependent flush_dcache_mmap_lock,
+ * within bdi.wb->list_lock in __sync_single_inode)
*
* anon_vma->rwsem,mapping->i_mmap_rwsem (memory_failure, collect_procs_anon)
* ->tasklist_lock
--
2.39.1
next prev parent reply other threads:[~2023-02-16 5:20 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-16 5:17 [PATCH v3 00/35] Per-VMA locks Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 01/35] maple_tree: Be more cautious about dead nodes Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 02/35] maple_tree: Detect dead nodes in mas_start() Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 03/35] maple_tree: Fix freeing of nodes in rcu mode Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 04/35] maple_tree: remove extra smp_wmb() from mas_dead_leaves() Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 05/35] maple_tree: Fix write memory barrier of nodes once dead for RCU mode Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 06/35] maple_tree: Add smp_rmb() to dead node detection Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 07/35] maple_tree: Add RCU lock checking to rcu callback functions Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 08/35] mm: Enable maple tree RCU mode by default Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 09/35] mm: introduce CONFIG_PER_VMA_LOCK Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 10/35] mm: rcu safe VMA freeing Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 11/35] mm: move mmap_lock assert function definitions Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 12/35] mm: add per-VMA lock and helper functions to control it Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 13/35] mm: mark VMA as being written when changing vm_flags Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 14/35] mm/mmap: move VMA locking before vma_adjust_trans_huge call Suren Baghdasaryan
2023-02-16 5:17 ` Suren Baghdasaryan [this message]
2023-02-16 5:17 ` [PATCH v3 16/35] mm/mmap: write-lock VMAs before merging, splitting or expanding them Suren Baghdasaryan
2023-02-23 14:51 ` Hyeonggon Yoo
2023-02-23 14:59 ` Hyeonggon Yoo
2023-02-23 17:46 ` Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 17/35] mm/mmap: write-lock VMA before shrinking or expanding it Suren Baghdasaryan
2023-02-23 20:20 ` Liam R. Howlett
2023-02-23 20:28 ` Liam R. Howlett
2023-02-23 21:16 ` Suren Baghdasaryan
2023-02-24 1:46 ` Liam R. Howlett
2023-02-24 2:06 ` Suren Baghdasaryan
2023-02-24 16:14 ` Liam R. Howlett
2023-02-24 16:19 ` Suren Baghdasaryan
2023-02-27 17:33 ` Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 18/35] mm/mremap: write-lock VMA while remapping it to a new address range Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 19/35] mm: write-lock VMAs before removing them from VMA tree Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 20/35] mm: conditionally write-lock VMA in free_pgtables Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 21/35] mm/mmap: write-lock adjacent VMAs if they can grow into unmapped area Suren Baghdasaryan
2023-02-16 15:34 ` Liam R. Howlett
2023-02-16 19:36 ` Suren Baghdasaryan
2023-02-17 14:50 ` Liam R. Howlett
2023-02-17 15:54 ` Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 22/35] kernel/fork: assert no VMA readers during its destruction Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 23/35] mm/mmap: prevent pagefault handler from racing with mmu_notifier registration Suren Baghdasaryan
2023-02-23 20:06 ` Liam R. Howlett
2023-02-23 20:29 ` Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 24/35] mm: introduce vma detached flag Suren Baghdasaryan
2023-02-23 20:08 ` Liam R. Howlett
2023-02-23 20:34 ` Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 25/35] mm: introduce lock_vma_under_rcu to be used from arch-specific code Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 26/35] mm: fall back to mmap_lock if vma->anon_vma is not yet set Suren Baghdasaryan
2023-02-16 15:44 ` Matthew Wilcox
2023-02-16 19:43 ` Suren Baghdasaryan
2023-02-17 2:14 ` Suren Baghdasaryan
2023-02-17 10:21 ` Hyeonggon Yoo
2023-02-17 16:13 ` Suren Baghdasaryan
2023-02-17 18:49 ` Hyeonggon Yoo
2023-02-17 16:05 ` Matthew Wilcox
2023-02-17 16:10 ` Suren Baghdasaryan
2023-04-03 19:49 ` Matthew Wilcox
2023-02-16 5:17 ` [PATCH v3 27/35] mm: add FAULT_FLAG_VMA_LOCK flag Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 28/35] mm: prevent do_swap_page from handling page faults under VMA lock Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 29/35] mm: prevent userfaults to be handled under per-vma lock Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 30/35] mm: introduce per-VMA lock statistics Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 31/35] x86/mm: try VMA lock-based page fault handling first Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 32/35] arm64/mm: " Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 33/35] powerc/mm: " Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 34/35] mm/mmap: free vm_area_struct without call_rcu in exit_mmap Suren Baghdasaryan
2023-02-16 5:17 ` [PATCH v3 35/35] mm: separate vma->lock from vm_area_struct Suren Baghdasaryan
2023-02-24 9:21 ` [PATCH v3 00/35] Per-VMA locks freak07
2023-02-27 16:50 ` Davidlohr Bueso
2023-02-27 17:22 ` Suren Baghdasaryan
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