From: Christoph Hellwig <hch@lst.de> To: Andrew Morton <akpm@linux-foundation.org>, Matthew Wilcox <willy@infradead.org>, Hugh Dickins <hughd@google.com> Cc: linux-afs@lists.infradead.org, linux-btrfs@vger.kernel.org, linux-ext4@vger.kernel.org, cluster-devel@redhat.com, linux-mm@kvack.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-nilfs@vger.kernel.org Subject: [PATCH 5/7] shmem: open code the page cache lookup in shmem_get_folio_gfp Date: Tue, 7 Mar 2023 15:34:08 +0100 [thread overview] Message-ID: <20230307143410.28031-6-hch@lst.de> (raw) In-Reply-To: <20230307143410.28031-1-hch@lst.de> Use the very low level filemap_get_entry helper to look up the entry in the xarray, and then: - don't bother locking the folio if only doing a userfault notification - open code locking the page and checking for truncation in a related code block This will allow to eventually remove the FGP_ENTRY flag. Signed-off-by: Christoph Hellwig <hch@lst.de> --- mm/shmem.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index 3705437c5757ba..714ff3fb02a938 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1856,12 +1856,10 @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, sbinfo = SHMEM_SB(inode->i_sb); charge_mm = vma ? vma->vm_mm : NULL; - folio = __filemap_get_folio(mapping, index, FGP_ENTRY | FGP_LOCK, 0); + folio = filemap_get_entry(mapping, index); if (folio && vma && userfaultfd_minor(vma)) { - if (!xa_is_value(folio)) { - folio_unlock(folio); + if (!xa_is_value(folio)) folio_put(folio); - } *fault_type = handle_userfault(vmf, VM_UFFD_MINOR); return 0; } @@ -1877,6 +1875,14 @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, } if (folio) { + folio_lock(folio); + + /* Has the page been truncated? */ + if (unlikely(folio->mapping != mapping)) { + folio_unlock(folio); + folio_put(folio); + goto repeat; + } if (sgp == SGP_WRITE) folio_mark_accessed(folio); if (folio_test_uptodate(folio)) -- 2.39.1
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de> To: cluster-devel.redhat.com Subject: [Cluster-devel] [PATCH 5/7] shmem: open code the page cache lookup in shmem_get_folio_gfp Date: Tue, 7 Mar 2023 15:34:08 +0100 [thread overview] Message-ID: <20230307143410.28031-6-hch@lst.de> (raw) In-Reply-To: <20230307143410.28031-1-hch@lst.de> Use the very low level filemap_get_entry helper to look up the entry in the xarray, and then: - don't bother locking the folio if only doing a userfault notification - open code locking the page and checking for truncation in a related code block This will allow to eventually remove the FGP_ENTRY flag. Signed-off-by: Christoph Hellwig <hch@lst.de> --- mm/shmem.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index 3705437c5757ba..714ff3fb02a938 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1856,12 +1856,10 @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, sbinfo = SHMEM_SB(inode->i_sb); charge_mm = vma ? vma->vm_mm : NULL; - folio = __filemap_get_folio(mapping, index, FGP_ENTRY | FGP_LOCK, 0); + folio = filemap_get_entry(mapping, index); if (folio && vma && userfaultfd_minor(vma)) { - if (!xa_is_value(folio)) { - folio_unlock(folio); + if (!xa_is_value(folio)) folio_put(folio); - } *fault_type = handle_userfault(vmf, VM_UFFD_MINOR); return 0; } @@ -1877,6 +1875,14 @@ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, } if (folio) { + folio_lock(folio); + + /* Has the page been truncated? */ + if (unlikely(folio->mapping != mapping)) { + folio_unlock(folio); + folio_put(folio); + goto repeat; + } if (sgp == SGP_WRITE) folio_mark_accessed(folio); if (folio_test_uptodate(folio)) -- 2.39.1
next prev parent reply other threads:[~2023-03-07 14:40 UTC|newest] Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-03-07 14:34 return an ERR_PTR from __filemap_get_folio v3 Christoph Hellwig 2023-03-07 14:34 ` Christoph Hellwig 2023-03-07 14:34 ` [Cluster-devel] " Christoph Hellwig 2023-03-07 14:34 ` [PATCH 1/7] mm: don't look at xarray value entries in split_huge_pages_in_file Christoph Hellwig 2023-03-07 14:34 ` Christoph Hellwig 2023-03-07 14:34 ` [Cluster-devel] " Christoph Hellwig 2023-03-07 14:34 ` [PATCH 2/7] mm: make mapping_get_entry available outside of filemap.c Christoph Hellwig 2023-03-07 14:34 ` Christoph Hellwig 2023-03-07 14:34 ` [Cluster-devel] " Christoph Hellwig 2023-03-07 14:34 ` [PATCH 3/7] mm: use filemap_get_entry in filemap_get_incore_folio Christoph Hellwig 2023-03-07 14:34 ` [Cluster-devel] " Christoph Hellwig 2023-03-07 14:34 ` [PATCH 4/7] shmem: remove shmem_get_partial_folio Christoph Hellwig 2023-03-07 14:34 ` [Cluster-devel] " Christoph Hellwig 2023-03-20 5:19 ` Hugh Dickins 2023-03-20 5:19 ` [Cluster-devel] " Hugh Dickins 2023-03-20 13:58 ` Christoph Hellwig 2023-03-20 13:58 ` Christoph Hellwig 2023-03-20 13:58 ` [Cluster-devel] " Christoph Hellwig 2023-03-07 14:34 ` Christoph Hellwig [this message] 2023-03-07 14:34 ` [Cluster-devel] [PATCH 5/7] shmem: open code the page cache lookup in shmem_get_folio_gfp Christoph Hellwig 2023-03-20 5:23 ` Hugh Dickins 2023-03-20 5:23 ` Hugh Dickins 2023-03-20 5:23 ` [Cluster-devel] " Hugh Dickins 2023-03-07 14:34 ` [PATCH 6/7] mm: remove FGP_ENTRY Christoph Hellwig 2023-03-07 14:34 ` Christoph Hellwig 2023-03-07 14:34 ` [Cluster-devel] " Christoph Hellwig 2023-03-07 14:34 ` [PATCH 7/7] mm: return an ERR_PTR from __filemap_get_folio Christoph Hellwig 2023-03-07 14:34 ` [Cluster-devel] " Christoph Hellwig 2023-03-07 15:23 ` [Cluster-devel] return an ERR_PTR from __filemap_get_folio v3 Andreas Gruenbacher 2023-03-07 15:23 ` Andreas Gruenbacher 2023-03-07 15:23 ` [Cluster-devel] " Andreas Gruenbacher -- strict thread matches above, loose matches on Subject: below -- 2023-01-21 6:57 return an ERR_PTR from __filemap_get_folio v2 Christoph Hellwig 2023-01-21 6:57 ` [PATCH 5/7] shmem: open code the page cache lookup in shmem_get_folio_gfp Christoph Hellwig 2023-01-21 6:57 ` Christoph Hellwig
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20230307143410.28031-6-hch@lst.de \ --to=hch@lst.de \ --cc=akpm@linux-foundation.org \ --cc=cluster-devel@redhat.com \ --cc=hughd@google.com \ --cc=linux-afs@lists.infradead.org \ --cc=linux-btrfs@vger.kernel.org \ --cc=linux-ext4@vger.kernel.org \ --cc=linux-fsdevel@vger.kernel.org \ --cc=linux-mm@kvack.org \ --cc=linux-nilfs@vger.kernel.org \ --cc=linux-xfs@vger.kernel.org \ --cc=willy@infradead.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.