From: Michel Lespinasse <michel@lespinasse.org>
To: Linux-MM <linux-mm@kvack.org>,
linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>
Cc: kernel-team@fb.com, Laurent Dufour <ldufour@linux.ibm.com>,
Jerome Glisse <jglisse@google.com>,
Peter Zijlstra <peterz@infradead.org>,
Michal Hocko <mhocko@suse.com>, Vlastimil Babka <vbabka@suse.cz>,
Davidlohr Bueso <dave@stgolabs.net>,
Matthew Wilcox <willy@infradead.org>,
Liam Howlett <liam.howlett@oracle.com>,
Rik van Riel <riel@surriel.com>,
Paul McKenney <paulmck@kernel.org>,
Song Liu <songliubraving@fb.com>,
Suren Baghdasaryan <surenb@google.com>,
Minchan Kim <minchan@google.com>,
Joel Fernandes <joelaf@google.com>,
David Rientjes <rientjes@google.com>,
Axel Rasmussen <axelrasmussen@google.com>,
Andy Lutomirski <luto@kernel.org>,
Michel Lespinasse <michel@lespinasse.org>
Subject: [PATCH v2 26/35] mm: implement speculative handling in wp_page_copy()
Date: Fri, 28 Jan 2022 05:09:57 -0800 [thread overview]
Message-ID: <20220128131006.67712-27-michel@lespinasse.org> (raw)
In-Reply-To: <20220128131006.67712-1-michel@lespinasse.org>
Change wp_page_copy() to handle the speculative case. This involves
aborting speculative faults if they have to allocate an anon_vma,
read-locking the mmu_notifier_lock to avoid races with
mmu_notifier_register(), and using pte_map_lock() instead of
pte_offset_map_lock() to complete the page fault.
Also change call sites to clear vmf->pte after unmapping the page table,
in order to satisfy pte_map_lock()'s preconditions.
Signed-off-by: Michel Lespinasse <michel@lespinasse.org>
---
mm/memory.c | 42 +++++++++++++++++++++++++++++++++---------
1 file changed, 33 insertions(+), 9 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c
index 73b1a328b797..fd8984d89109 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3087,20 +3087,27 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
pte_t entry;
int page_copied = 0;
struct mmu_notifier_range range;
+ vm_fault_t ret = VM_FAULT_OOM;
- if (unlikely(anon_vma_prepare(vma)))
- goto oom;
+ if (unlikely(!vma->anon_vma)) {
+ if (vmf->flags & FAULT_FLAG_SPECULATIVE) {
+ ret = VM_FAULT_RETRY;
+ goto out;
+ }
+ if (__anon_vma_prepare(vma))
+ goto out;
+ }
if (is_zero_pfn(pte_pfn(vmf->orig_pte))) {
new_page = alloc_zeroed_user_highpage_movable(vma,
vmf->address);
if (!new_page)
- goto oom;
+ goto out;
} else {
new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma,
vmf->address);
if (!new_page)
- goto oom;
+ goto out;
if (!cow_user_page(new_page, old_page, vmf)) {
/*
@@ -3117,11 +3124,16 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
}
if (mem_cgroup_charge(page_folio(new_page), mm, GFP_KERNEL))
- goto oom_free_new;
+ goto out_free_new;
cgroup_throttle_swaprate(new_page, GFP_KERNEL);
__SetPageUptodate(new_page);
+ if ((vmf->flags & FAULT_FLAG_SPECULATIVE) &&
+ !mmu_notifier_trylock(mm)) {
+ ret = VM_FAULT_RETRY;
+ goto out_free_new;
+ }
mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm,
vmf->address & PAGE_MASK,
(vmf->address & PAGE_MASK) + PAGE_SIZE);
@@ -3130,7 +3142,11 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
/*
* Re-check the pte - we dropped the lock
*/
- vmf->pte = pte_offset_map_lock(mm, vmf->pmd, vmf->address, &vmf->ptl);
+ if (!pte_map_lock(vmf)) {
+ ret = VM_FAULT_RETRY;
+ /* put_page() will uncharge the page */
+ goto out_notify;
+ }
if (likely(pte_same(*vmf->pte, vmf->orig_pte))) {
if (old_page) {
if (!PageAnon(old_page)) {
@@ -3205,6 +3221,8 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
* the above ptep_clear_flush_notify() did already call it.
*/
mmu_notifier_invalidate_range_only_end(&range);
+ if (vmf->flags & FAULT_FLAG_SPECULATIVE)
+ mmu_notifier_unlock(mm);
if (old_page) {
/*
* Don't let another task, with possibly unlocked vma,
@@ -3221,12 +3239,16 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
put_page(old_page);
}
return page_copied ? VM_FAULT_WRITE : 0;
-oom_free_new:
+out_notify:
+ mmu_notifier_invalidate_range_only_end(&range);
+ if (vmf->flags & FAULT_FLAG_SPECULATIVE)
+ mmu_notifier_unlock(mm);
+out_free_new:
put_page(new_page);
-oom:
+out:
if (old_page)
put_page(old_page);
- return VM_FAULT_OOM;
+ return ret;
}
/**
@@ -3369,6 +3391,7 @@ static vm_fault_t do_wp_page(struct vm_fault *vmf)
return wp_pfn_shared(vmf);
pte_unmap_unlock(vmf->pte, vmf->ptl);
+ vmf->pte = NULL;
return wp_page_copy(vmf);
}
@@ -3407,6 +3430,7 @@ static vm_fault_t do_wp_page(struct vm_fault *vmf)
get_page(vmf->page);
pte_unmap_unlock(vmf->pte, vmf->ptl);
+ vmf->pte = NULL;
return wp_page_copy(vmf);
}
--
2.20.1
next prev parent reply other threads:[~2022-01-28 13:20 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-28 13:09 [PATCH v2 00/35] Speculative page faults Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 01/35] mm: export dump_mm Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 02/35] mmap locking API: mmap_lock_is_contended returns a bool Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 03/35] mmap locking API: name the return values Michel Lespinasse
2022-01-31 16:17 ` Liam Howlett
2022-02-07 17:39 ` Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 04/35] do_anonymous_page: use update_mmu_tlb() Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 05/35] do_anonymous_page: reduce code duplication Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 06/35] mm: introduce CONFIG_SPECULATIVE_PAGE_FAULT Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 07/35] x86/mm: define ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 08/35] mm: add FAULT_FLAG_SPECULATIVE flag Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 09/35] mm: add do_handle_mm_fault() Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 10/35] mm: add per-mm mmap sequence counter for speculative page fault handling Michel Lespinasse
2022-08-25 11:23 ` Pavan Kondeti
2022-01-28 13:09 ` [PATCH v2 11/35] mm: rcu safe vma freeing Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 12/35] mm: separate mmap locked assertion from find_vma Michel Lespinasse
2022-01-29 0:08 ` kernel test robot
2022-01-29 0:33 ` Michel Lespinasse
2022-01-31 14:44 ` Matthew Wilcox
2022-02-04 22:41 ` Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 13/35] x86/mm: attempt speculative mm faults first Michel Lespinasse
2022-02-01 17:16 ` Liam Howlett
2022-02-07 17:39 ` Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 14/35] mm: add speculative_page_walk_begin() and speculative_page_walk_end() Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 15/35] mm: refactor __handle_mm_fault() / handle_pte_fault() Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 16/35] mm: implement speculative handling in __handle_mm_fault() Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 17/35] mm: add pte_map_lock() and pte_spinlock() Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 18/35] mm: implement speculative handling in do_anonymous_page() Michel Lespinasse
2022-01-28 21:03 ` kernel test robot
2022-01-28 22:08 ` Michel Lespinasse
2022-01-30 2:54 ` [mm] fa5331bae2: canonical_address#:#[##] kernel test robot
2022-01-30 5:08 ` Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 19/35] mm: enable speculative fault handling through do_anonymous_page() Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 20/35] mm: implement speculative handling in do_numa_page() Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 21/35] mm: enable speculative fault " Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 22/35] percpu-rwsem: enable percpu_sem destruction in atomic context Michel Lespinasse
[not found] ` <20220129121319.3593-1-hdanton@sina.com>
2022-01-31 18:04 ` Suren Baghdasaryan
[not found] ` <20220201020958.3720-1-hdanton@sina.com>
2022-02-07 19:31 ` Suren Baghdasaryan
[not found] ` <20220208002059.2670-1-hdanton@sina.com>
2022-02-08 1:31 ` Suren Baghdasaryan
2022-01-28 13:09 ` [PATCH v2 23/35] mm: add mmu_notifier_lock Michel Lespinasse
2022-07-27 7:34 ` Pavan Kondeti
2022-07-27 20:30 ` Suren Baghdasaryan
2022-01-28 13:09 ` [PATCH v2 24/35] mm: write lock mmu_notifier_lock when registering mmu notifiers Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 25/35] mm: add mmu_notifier_trylock() and mmu_notifier_unlock() Michel Lespinasse
2022-01-28 13:09 ` Michel Lespinasse [this message]
2022-01-28 13:09 ` [PATCH v2 27/35] mm: implement and enable speculative fault handling in handle_pte_fault() Michel Lespinasse
2022-01-28 13:09 ` [PATCH v2 28/35] mm: disable speculative faults for single threaded user space Michel Lespinasse
2022-01-28 13:10 ` [PATCH v2 29/35] mm: disable rcu safe vma freeing " Michel Lespinasse
2022-01-28 13:10 ` [PATCH v2 30/35] mm: create new include/linux/vm_event.h header file Michel Lespinasse
2022-01-28 13:10 ` [PATCH v2 31/35] mm: anon spf statistics Michel Lespinasse
2022-01-28 13:10 ` [PATCH v2 32/35] arm64/mm: define ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT Michel Lespinasse
2022-01-28 13:10 ` [PATCH v2 33/35] arm64/mm: attempt speculative mm faults first Michel Lespinasse
2022-01-30 9:13 ` Mike Rapoport
2022-01-31 8:07 ` Michel Lespinasse
2022-02-01 8:58 ` Mike Rapoport
2022-02-07 17:39 ` Michel Lespinasse
2022-02-08 9:07 ` Mike Rapoport
2022-01-28 13:10 ` [PATCH v2 34/35] powerpc/mm: define ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT Michel Lespinasse
2022-01-28 13:10 ` [PATCH v2 35/35] powerpc/mm: attempt speculative mm faults first Michel Lespinasse
2022-01-31 9:56 ` [PATCH v2 00/35] Speculative page faults David Hildenbrand
2022-01-31 17:00 ` Suren Baghdasaryan
2022-02-01 1:14 ` Andrew Morton
2022-02-01 2:20 ` Matthew Wilcox
2022-02-07 17:39 ` Michel Lespinasse
2022-02-01 17:17 ` Sebastian Andrzej Siewior
2022-02-23 16:11 ` Mel Gorman
2022-03-08 5:37 ` Suren Baghdasaryan
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