From: Peter Xu <peterx@redhat.com>
To: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
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 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>,
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>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 15/31] mm/userfaultfd: allow pte_offset_map_lock() to fail
Date: Wed, 24 May 2023 18:44:11 -0400 [thread overview]
Message-ID: <ZG6TOyH7NJIgXxGX@x1n> (raw)
In-Reply-To: <49d92b15-3442-4e84-39bd-c77c316bf844@google.com>
Hi, Hugh,
On Sun, May 21, 2023 at 10:07:35PM -0700, Hugh Dickins wrote:
> mfill_atomic_install_pte() and mfill_atomic_pte_zeropage() treat
> failed pte_offset_map_lock() as -EFAULT, with no attempt to retry.
Could you help explain why it should be -EFAULT, not -EAGAIN or -EEXIST?
IIUC right now if pte existed we have -EEXIST returned as part of the
userfault ABI, no matter whether it's pte or thp.
IMHO it may boil down to my limited knowledge on how pte_offset_map_lock()
is used after this part 2 series, and I assume the core changes will be in
your 3rd series (besides this one and the arch one).
Please shed some light if there's quick answers (IIUC this is for speeding
up collapsing shmem thps, but still no much clue here), or I can also wait
for reading the 3rd part if it'll come soon in any form.
Thanks,
--
Peter Xu
next prev parent reply other threads:[~2023-05-24 22:44 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-22 4:46 [PATCH 00/31] mm: allow pte_offset_map[_lock]() " Hugh Dickins
2023-05-22 4:49 ` [PATCH 01/31] mm: use pmdp_get_lockless() without surplus barrier() Hugh Dickins
2023-05-24 22:29 ` Peter Xu
2023-05-25 22:35 ` Hugh Dickins
2023-05-26 16:48 ` Peter Xu
2023-05-24 22:54 ` Yu Zhao
2023-05-22 4:51 ` [PATCH 02/31] mm/migrate: remove cruft from migration_entry_wait()s Hugh Dickins
2023-05-23 1:45 ` Alistair Popple
2023-05-24 1:57 ` Hugh Dickins
2023-05-22 4:52 ` [PATCH 03/31] mm/pgtable: kmap_local_page() instead of kmap_atomic() Hugh Dickins
2023-05-26 22:22 ` Peter Xu
2023-05-26 22:42 ` Peter Xu
2023-05-22 4:53 ` [PATCH 04/31] mm/pgtable: allow pte_offset_map[_lock]() to fail Hugh Dickins
2023-05-22 11:17 ` Qi Zheng
2023-05-24 2:22 ` Hugh Dickins
2023-05-24 3:11 ` Qi Zheng
2023-07-05 14:48 ` Aneesh Kumar K.V
2023-07-05 22:26 ` Hugh Dickins
2023-05-22 4:54 ` [PATCH 05/31] mm/filemap: allow pte_offset_map_lock() " Hugh Dickins
2023-05-22 11:23 ` Qi Zheng
2023-05-24 2:35 ` Hugh Dickins
2023-05-24 3:14 ` Qi Zheng
2023-05-22 4:55 ` [PATCH 06/31] mm/page_vma_mapped: delete bogosity in page_vma_mapped_walk() Hugh Dickins
2023-05-22 4:57 ` [PATCH 07/31] mm/page_vma_mapped: reformat map_pte() with less indentation Hugh Dickins
2023-05-22 4:58 ` [PATCH 08/31] mm/page_vma_mapped: pte_offset_map_nolock() not pte_lockptr() Hugh Dickins
2023-05-22 11:41 ` Qi Zheng
2023-05-24 2:44 ` Hugh Dickins
2023-05-22 5:00 ` [PATCH 09/31] mm/pagewalkers: ACTION_AGAIN if pte_offset_map_lock() fails Hugh Dickins
2023-05-23 18:07 ` SeongJae Park
2023-05-22 5:01 ` [PATCH 10/31] mm/pagewalk: walk_pte_range() allow for pte_offset_map() Hugh Dickins
2023-05-22 5:03 ` [PATCH 11/31] mm/vmwgfx: simplify pmd & pud mapping dirty helpers Hugh Dickins
2023-05-22 5:04 ` [PATCH 12/31] mm/vmalloc: vmalloc_to_page() use pte_offset_kernel() Hugh Dickins
2023-05-22 7:27 ` Lorenzo Stoakes
2023-05-22 5:05 ` [PATCH 13/31] mm/hmm: retry if pte_offset_map() fails Hugh Dickins
2023-05-22 12:11 ` Qi Zheng
2023-05-23 2:39 ` Alistair Popple
2023-05-23 6:06 ` Qi Zheng
2023-05-24 2:50 ` Hugh Dickins
2023-05-24 5:16 ` Alistair Popple
2023-05-22 5:06 ` [PATCH 14/31] fs/userfaultfd: " Hugh Dickins
2023-05-24 22:31 ` Peter Xu
2023-05-22 5:07 ` [PATCH 15/31] mm/userfaultfd: allow pte_offset_map_lock() to fail Hugh Dickins
2023-05-24 22:44 ` Peter Xu [this message]
2023-05-25 22:06 ` Hugh Dickins
2023-05-26 16:25 ` Peter Xu
2023-05-22 5:08 ` [PATCH 16/31] mm/debug_vm_pgtable,page_table_check: warn pte map fails Hugh Dickins
2023-05-22 5:10 ` [PATCH 17/31] mm/various: give up if pte_offset_map[_lock]() fails Hugh Dickins
2023-05-22 12:24 ` Qi Zheng
2023-05-22 12:37 ` Qi Zheng
2023-05-24 3:20 ` Hugh Dickins
2023-05-22 5:12 ` [PATCH 18/31] mm/mprotect: delete pmd_none_or_clear_bad_unless_trans_huge() Hugh Dickins
2023-05-22 5:13 ` [PATCH 19/31] mm/mremap: retry if either pte_offset_map_*lock() fails Hugh Dickins
2023-05-22 5:15 ` [PATCH 20/31] mm/madvise: clean up pte_offset_map_lock() scans Hugh Dickins
2023-05-22 5:17 ` [PATCH 21/31] mm/madvise: clean up force_shm_swapin_readahead() Hugh Dickins
2023-05-22 5:18 ` [PATCH 22/31] mm/swapoff: allow pte_offset_map[_lock]() to fail Hugh Dickins
2023-05-22 5:19 ` [PATCH 23/31] mm/mglru: allow pte_offset_map_nolock() " Hugh Dickins
2023-05-22 5:26 ` Yu Zhao
2023-05-22 5:20 ` [PATCH 24/31] mm/migrate_device: allow pte_offset_map_lock() " Hugh Dickins
2023-05-23 2:23 ` Alistair Popple
2023-05-24 3:45 ` Hugh Dickins
2023-05-24 5:11 ` Alistair Popple
2023-05-22 5:22 ` [PATCH 25/31] mm/gup: remove FOLL_SPLIT_PMD use of pmd_trans_unstable() Hugh Dickins
2023-05-23 2:26 ` Yang Shi
2023-05-23 2:44 ` Yang Shi
2023-05-24 4:26 ` Hugh Dickins
2023-05-24 22:45 ` Yang Shi
2023-05-25 21:16 ` Hugh Dickins
2023-05-25 22:33 ` Yang Shi
2023-05-22 5:23 ` [PATCH 26/31] mm/huge_memory: split huge pmd under one pte_offset_map() Hugh Dickins
2023-05-22 23:35 ` Yang Shi
2023-05-22 5:24 ` [PATCH 27/31] mm/khugepaged: allow pte_offset_map[_lock]() to fail Hugh Dickins
2023-05-22 23:54 ` Yang Shi
2023-05-24 4:44 ` Hugh Dickins
2023-05-24 21:59 ` Yang Shi
2023-05-22 5:25 ` [PATCH 28/31] mm/memory: " Hugh Dickins
2023-05-22 5:26 ` [PATCH 29/31] mm/memory: handle_pte_fault() use pte_offset_map_nolock() Hugh Dickins
2023-05-22 12:52 ` Qi Zheng
2023-05-24 4:54 ` Hugh Dickins
2023-05-22 5:27 ` [PATCH 30/31] mm/pgtable: delete pmd_trans_unstable() and friends Hugh Dickins
2023-05-22 5:29 ` [PATCH 31/31] perf/core: Allow pte_offset_map() to fail Hugh Dickins
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