From: Michel Lespinasse <michel@lespinasse.org>
To: Linux-MM <linux-mm@kvack.org>
Cc: Laurent Dufour <ldufour@linux.ibm.com>,
Peter Zijlstra <peterz@infradead.org>,
Michal Hocko <mhocko@suse.com>,
Matthew Wilcox <willy@infradead.org>,
Rik van Riel <riel@surriel.com>,
Paul McKenney <paulmck@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Suren Baghdasaryan <surenb@google.com>,
Joel Fernandes <joelaf@google.com>,
Rom Lemarchand <romlem@google.com>,
Linux-Kernel <linux-kernel@vger.kernel.org>,
Michel Lespinasse <michel@lespinasse.org>
Subject: [RFC PATCH 19/37] mm: implement speculative handling in wp_page_copy()
Date: Tue, 6 Apr 2021 18:44:44 -0700 [thread overview]
Message-ID: <20210407014502.24091-20-michel@lespinasse.org> (raw)
In-Reply-To: <20210407014502.24091-1-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, 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 | 31 ++++++++++++++++++++++---------
1 file changed, 22 insertions(+), 9 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c
index eea72bd78d06..547d9d0ee962 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2911,20 +2911,27 @@ 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)) {
/*
@@ -2941,7 +2948,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
}
if (mem_cgroup_charge(new_page, mm, GFP_KERNEL))
- goto oom_free_new;
+ goto out_free_new;
cgroup_throttle_swaprate(new_page, GFP_KERNEL);
__SetPageUptodate(new_page);
@@ -2954,7 +2961,11 @@ 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_free_new;
+ }
if (likely(pte_same(*vmf->pte, vmf->orig_pte))) {
if (old_page) {
if (!PageAnon(old_page)) {
@@ -3042,12 +3053,12 @@ 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_free_new:
put_page(new_page);
-oom:
+out:
if (old_page)
put_page(old_page);
- return VM_FAULT_OOM;
+ return ret;
}
/**
@@ -3190,6 +3201,7 @@ 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);
}
@@ -3228,6 +3240,7 @@ 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:[~2021-04-07 1:52 UTC|newest]
Thread overview: 85+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-07 1:44 [RFC PATCH 00/37] Speculative page faults Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 01/37] mmap locking API: mmap_lock_is_contended returns a bool Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 02/37] mmap locking API: name the return values Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 03/37] do_anonymous_page: use update_mmu_tlb() Michel Lespinasse
2021-04-07 2:06 ` Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 04/37] do_anonymous_page: reduce code duplication Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 05/37] mm: introduce CONFIG_SPECULATIVE_PAGE_FAULT Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 06/37] x86/mm: define ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 07/37] mm: add FAULT_FLAG_SPECULATIVE flag Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 08/37] mm: add do_handle_mm_fault() Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 09/37] mm: add per-mm mmap sequence counter for speculative page fault handling Michel Lespinasse
2021-04-07 14:47 ` Peter Zijlstra
2021-04-07 20:50 ` Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 10/37] mm: rcu safe vma freeing Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 11/37] x86/mm: attempt speculative mm faults first Michel Lespinasse
2021-04-07 14:48 ` Peter Zijlstra
2021-04-07 15:35 ` Matthew Wilcox
2021-04-07 20:32 ` Michel Lespinasse
2021-04-07 20:14 ` Michel Lespinasse
2021-04-07 20:18 ` Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 12/37] mm: refactor __handle_mm_fault() / handle_pte_fault() Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 13/37] mm: implement speculative handling in __handle_mm_fault() Michel Lespinasse
2021-04-07 15:36 ` Andy Lutomirski
2021-04-28 14:58 ` Michel Lespinasse
2021-04-28 15:13 ` Andy Lutomirski
2021-04-28 16:11 ` Paul E. McKenney
2021-04-29 0:02 ` Michel Lespinasse
2021-04-29 0:05 ` Andy Lutomirski
2021-04-29 16:12 ` Matthew Wilcox
2021-04-29 18:04 ` Andy Lutomirski
2021-04-29 19:14 ` Michel Lespinasse
2021-04-29 19:34 ` Matthew Wilcox
2021-04-29 23:56 ` Michel Lespinasse
2021-04-29 15:52 ` Paul E. McKenney
2021-04-29 18:34 ` Paul E. McKenney
2021-04-29 18:49 ` Matthew Wilcox
2021-05-03 3:14 ` Paul E. McKenney
2021-04-29 21:17 ` Michel Lespinasse
2021-05-03 3:40 ` Paul E. McKenney
2021-05-03 4:34 ` Michel Lespinasse
2021-05-03 16:32 ` Paul E. McKenney
2021-04-07 1:44 ` [RFC PATCH 14/37] mm: add pte_map_lock() and pte_spinlock() Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 15/37] mm: implement speculative handling in do_anonymous_page() Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 16/37] mm: enable speculative fault handling through do_anonymous_page() Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 17/37] mm: implement speculative handling in do_numa_page() Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 18/37] mm: enable speculative fault " Michel Lespinasse
2021-04-07 1:44 ` Michel Lespinasse [this message]
2021-04-07 1:44 ` [RFC PATCH 20/37] mm: implement and enable speculative fault handling in handle_pte_fault() Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 21/37] mm: implement speculative handling in do_swap_page() Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 22/37] mm: enable speculative fault handling through do_swap_page() Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 23/37] mm: rcu safe vma->vm_file freeing Michel Lespinasse
2021-04-08 5:12 ` [mm] 87b1c39af4: nvml.blk_rw_mt_TEST0_check_pmem_debug.fail kernel test robot
2021-04-07 1:44 ` [RFC PATCH 24/37] mm: implement speculative handling in __do_fault() Michel Lespinasse
2021-04-07 2:35 ` Matthew Wilcox
2021-04-07 2:53 ` Michel Lespinasse
2021-04-07 3:01 ` Matthew Wilcox
2021-04-07 14:40 ` Peter Zijlstra
2021-04-07 21:20 ` Michel Lespinasse
2021-04-07 21:27 ` Matthew Wilcox
2021-04-08 7:00 ` Peter Zijlstra
2021-04-08 7:13 ` Matthew Wilcox
2021-04-08 8:18 ` Peter Zijlstra
2021-04-08 8:37 ` Michel Lespinasse
2021-04-08 11:28 ` Matthew Wilcox
2021-04-07 1:44 ` [RFC PATCH 25/37] mm: implement speculative handling in filemap_fault() Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 26/37] mm: implement speculative fault handling in finish_fault() Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 27/37] mm: implement speculative handling in do_fault_around() Michel Lespinasse
2021-04-07 2:37 ` Matthew Wilcox
2021-04-07 1:44 ` [RFC PATCH 28/37] mm: implement speculative handling in filemap_map_pages() Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 29/37] fs: list file types that support speculative faults Michel Lespinasse
2021-04-07 2:39 ` Matthew Wilcox
2021-04-07 1:44 ` [RFC PATCH 30/37] mm: enable speculative fault handling for supported file types Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 31/37] ext4: implement speculative fault handling Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 32/37] f2fs: " Michel Lespinasse
2021-04-07 1:44 ` [RFC PATCH 33/37] mm: enable speculative fault handling only for multithreaded user space Michel Lespinasse
2021-04-07 2:48 ` Matthew Wilcox
2021-04-07 1:44 ` [RFC PATCH 34/37] mm: rcu safe vma freeing " Michel Lespinasse
2021-04-07 2:50 ` Matthew Wilcox
2021-04-08 7:53 ` Michel Lespinasse
2021-04-07 1:45 ` [RFC PATCH 35/37] mm: spf statistics Michel Lespinasse
2021-04-07 1:45 ` [RFC PATCH 36/37] arm64/mm: define ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT Michel Lespinasse
2021-04-07 1:45 ` [RFC PATCH 37/37] arm64/mm: attempt speculative mm faults first Michel Lespinasse
2021-04-21 1:44 ` [RFC PATCH 00/37] Speculative page faults Chinwen Chang
2021-06-28 22:14 ` Axel Rasmussen
2021-07-21 11:33 ` vjitta
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