From: Hugh Dickins <hughd@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Mike Rapoport <rppt@kernel.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Matthew Wilcox <willy@infradead.org>,
David Hildenbrand <david@redhat.com>,
Suren Baghdasaryan <surenb@google.com>,
Qi Zheng <zhengqi.arch@bytedance.com>,
Yang Shi <shy828301@gmail.com>,
Mel Gorman <mgorman@techsingularity.net>,
Peter Xu <peterx@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Will Deacon <will@kernel.org>, Yu Zhao <yuzhao@google.com>,
Alistair Popple <apopple@nvidia.com>,
Ralph Campbell <rcampbell@nvidia.com>,
Ira Weiny <ira.weiny@intel.com>,
Steven Price <steven.price@arm.com>,
SeongJae Park <sj@kernel.org>,
Lorenzo Stoakes <lstoakes@gmail.com>,
Huang Ying <ying.huang@intel.com>,
Naoya Horiguchi <naoya.horiguchi@nec.com>,
Christophe Leroy <christophe.leroy@csgroup.eu>,
Zack Rusin <zackr@vmware.com>, Jason Gunthorpe <jgg@ziepe.ca>,
Axel Rasmussen <axelrasmussen@google.com>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Pasha Tatashin <pasha.tatashin@soleen.com>,
Miaohe Lin <linmiaohe@huawei.com>,
Minchan Kim <minchan@kernel.org>,
Christoph Hellwig <hch@infradead.org>, Song Liu <song@kernel.org>,
Thomas Hellstrom <thomas.hellstrom@linux.intel.com>,
Ryan Roberts <ryan.roberts@arm.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH v2 28/32] mm/memory: allow pte_offset_map[_lock]() to fail
Date: Fri, 9 Jun 2023 13:11:18 -0700 (PDT) [thread overview]
Message-ID: <11a9744a-e7f-33d0-474-c2f2eb7e079@google.com> (raw)
In-Reply-To: <20230609130632.ec6ffe72fc5f7952af4a3e54@linux-foundation.org>
On Fri, 9 Jun 2023, Andrew Morton wrote:
> On Thu, 8 Jun 2023 18:43:38 -0700 (PDT) Hugh Dickins <hughd@google.com> wrote:
>
> > copy_pte_range(): use pte_offset_map_nolock(), and allow for it to fail;
> > but with a comment on some further assumptions that are being made there.
> >
> > zap_pte_range() and zap_pmd_range(): adjust their interaction so that
> > a pte_offset_map_lock() failure in zap_pte_range() leads to a retry in
> > zap_pmd_range(); remove call to pmd_none_or_trans_huge_or_clear_bad().
> >
> > Allow pte_offset_map_lock() to fail in many functions. Update comment
> > on calling pte_alloc() in do_anonymous_page(). Remove redundant calls
> > to pmd_trans_unstable(), pmd_devmap_trans_unstable(), pmd_none() and
> > pmd_bad(); but leave pmd_none_or_clear_bad() calls in free_pmd_range()
> > and copy_pmd_range(), those do simplify the next level down.
> >
> > ...
> >
> > @@ -3728,11 +3737,9 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
> > vmf->page = pfn_swap_entry_to_page(entry);
> > vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd,
> > vmf->address, &vmf->ptl);
> > - if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) {
> > - spin_unlock(vmf->ptl);
> > - goto out;
> > - }
> > -
> > + if (unlikely(!vmf->pte ||
> > + !pte_same(*vmf->pte, vmf->orig_pte)))
> > + goto unlock;
> > /*
> > * Get a page reference while we know the page can't be
> > * freed.
>
> This hunk falls afoul of
> https://lkml.kernel.org/r/20230602092949.545577-5-ryan.roberts@arm.com.
>
> I did this:
>
> @@ -3729,7 +3738,8 @@ vm_fault_t do_swap_page(struct vm_fault
> vmf->page = pfn_swap_entry_to_page(entry);
> vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd,
> vmf->address, &vmf->ptl);
> - if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte)))
> + if (unlikely(!vmf->pte ||
> + !pte_same(*vmf->pte, vmf->orig_pte)))
> goto unlock;
>
> /*
Yes, that's exactly right: thanks, Andrew.
Hugh
next prev parent reply other threads:[~2023-06-09 20:11 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-09 0:54 [PATCH v2 00/32] mm: allow pte_offset_map[_lock]() to fail Hugh Dickins
2023-06-09 1:06 ` [PATCH v2 01/32] mm: use pmdp_get_lockless() without surplus barrier() Hugh Dickins
2023-06-09 1:08 ` [PATCH v2 02/32] mm/migrate: remove cruft from migration_entry_wait()s Hugh Dickins
2023-06-09 1:09 ` [PATCH v2 03/32] mm/pgtable: kmap_local_page() instead of kmap_atomic() Hugh Dickins
2023-06-09 1:10 ` [PATCH v2 04/32] mm/pgtable: allow pte_offset_map[_lock]() to fail Hugh Dickins
2023-07-11 1:23 ` Zi Yan
2023-07-28 13:53 ` Yongqin Liu
2023-07-28 14:05 ` Matthew Wilcox
2023-07-28 16:58 ` Hugh Dickins
2023-08-05 16:06 ` Yongqin Liu
2023-08-05 17:07 ` Matthew Wilcox
2023-08-08 0:29 ` John Hubbard
2023-06-09 1:11 ` [PATCH v2 05/32] mm/filemap: allow pte_offset_map_lock() " Hugh Dickins
2023-07-11 1:34 ` Zi Yan
2023-07-11 5:21 ` Hugh Dickins
2023-06-09 1:12 ` [PATCH v2 06/32] mm/page_vma_mapped: delete bogosity in page_vma_mapped_walk() Hugh Dickins
2023-07-11 1:47 ` Zi Yan
2023-06-09 1:14 ` [PATCH v2 07/32] mm/page_vma_mapped: reformat map_pte() with less indentation Hugh Dickins
2023-07-11 1:56 ` Zi Yan
2023-06-09 1:15 ` [PATCH v2 08/32] mm/page_vma_mapped: pte_offset_map_nolock() not pte_lockptr() Hugh Dickins
2023-06-09 1:17 ` [PATCH v2 09/32] mm/pagewalkers: ACTION_AGAIN if pte_offset_map_lock() fails Hugh Dickins
2023-06-09 1:18 ` [PATCH v2 10/32] mm/pagewalk: walk_pte_range() allow for pte_offset_map() Hugh Dickins
2023-06-09 1:20 ` [PATCH v2 11/32] mm/vmwgfx: simplify pmd & pud mapping dirty helpers Hugh Dickins
2023-06-09 1:21 ` [PATCH v2 12/32] mm/vmalloc: vmalloc_to_page() use pte_offset_kernel() Hugh Dickins
2023-07-10 14:42 ` Mark Brown
2023-07-10 17:18 ` Lorenzo Stoakes
2023-07-10 17:33 ` Mark Brown
2023-07-11 4:34 ` Hugh Dickins
2023-07-11 15:34 ` Mark Brown
2023-07-11 16:13 ` Hugh Dickins
2023-07-11 16:34 ` Mark Brown
2023-07-11 17:57 ` Mark Brown
2023-07-13 11:19 ` Linux regression tracking #update (Thorsten Leemhuis)
2023-07-20 10:32 ` Will Deacon
2023-07-20 12:06 ` Mark Brown
2023-08-08 5:52 ` Linux regression tracking (Thorsten Leemhuis)
2023-08-08 11:09 ` Mark Brown
2023-08-11 8:00 ` Linux regression tracking #update (Thorsten Leemhuis)
2023-07-11 14:48 ` Linux regression tracking #adding (Thorsten Leemhuis)
2023-06-09 1:23 ` [PATCH v2 13/32] mm/hmm: retry if pte_offset_map() fails Hugh Dickins
2023-06-09 1:24 ` [PATCH v2 14/32] mm/userfaultfd: " Hugh Dickins
2023-06-09 1:26 ` [PATCH v2 15/32] mm/userfaultfd: allow pte_offset_map_lock() to fail Hugh Dickins
2023-06-09 1:27 ` [PATCH v2 16/32] mm/debug_vm_pgtable,page_table_check: warn pte map fails Hugh Dickins
2023-06-09 1:29 ` [PATCH v2 17/32] mm/various: give up if pte_offset_map[_lock]() fails Hugh Dickins
2023-06-09 1:30 ` [PATCH v2 18/32] mm/mprotect: delete pmd_none_or_clear_bad_unless_trans_huge() Hugh Dickins
2023-06-09 1:32 ` [PATCH v2 19/32] mm/mremap: retry if either pte_offset_map_*lock() fails Hugh Dickins
2023-06-09 1:34 ` [PATCH v2 20/32] mm/madvise: clean up pte_offset_map_lock() scans Hugh Dickins
2023-06-09 1:35 ` [PATCH v2 21/32] mm/madvise: clean up force_shm_swapin_readahead() Hugh Dickins
2023-06-09 1:36 ` [PATCH v2 22/32] mm/swapoff: allow pte_offset_map[_lock]() to fail Hugh Dickins
2023-06-09 1:37 ` [PATCH v2 23/32] mm/mglru: allow pte_offset_map_nolock() " Hugh Dickins
2023-06-09 1:38 ` [PATCH v2 24/32] mm/migrate_device: allow pte_offset_map_lock() " Hugh Dickins
2023-06-09 1:39 ` [PATCH v2 25/32] mm/gup: remove FOLL_SPLIT_PMD use of pmd_trans_unstable() Hugh Dickins
2023-06-09 18:24 ` Yang Shi
2023-06-09 1:41 ` [PATCH v2 26/32] mm/huge_memory: split huge pmd under one pte_offset_map() Hugh Dickins
2023-06-09 1:42 ` [PATCH v2 27/32] mm/khugepaged: allow pte_offset_map[_lock]() to fail Hugh Dickins
2023-06-09 1:43 ` [PATCH v2 28/32] mm/memory: " Hugh Dickins
2023-06-09 20:06 ` Andrew Morton
2023-06-09 20:11 ` Hugh Dickins [this message]
2023-06-12 9:10 ` Ryan Roberts
2023-06-15 23:10 ` [PATCH v2 28/32 fix] mm/memory: allow pte_offset_map[_lock]() to fail: fix Hugh Dickins
2023-06-09 1:45 ` [PATCH v2 29/32] mm/memory: handle_pte_fault() use pte_offset_map_nolock() Hugh Dickins
2023-06-09 1:50 ` [PATCH v2 30/32] mm/pgtable: delete pmd_trans_unstable() and friends Hugh Dickins
2023-06-09 1:52 ` [PATCH v2 31/32] mm/swap: swap_vma_readahead() do the pte_offset_map() Hugh Dickins
2023-06-12 8:03 ` Huang, Ying
2023-06-14 3:58 ` Hugh Dickins
2023-06-09 1:53 ` [PATCH v2 32/32] perf/core: Allow pte_offset_map() to fail Hugh Dickins
2023-06-20 6:50 ` [PATCH] mm/swapfile: delete outdated pte_offset_map() comment Hugh Dickins
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