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From: Matthew Wilcox <willy@infradead.org>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>,
	Andreas Dilger <adilger.kernel@dilger.ca>,
	Jan Kara <jack@suse.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Hugh Dickins <hughd@google.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Dave Hansen <dave.hansen@intel.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	Ross Zwisler <ross.zwisler@linux.intel.com>,
	linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-block@vger.kernel.org
Subject: Re: [PATCHv6 05/37] thp: try to free page's buffers before attempt split
Date: Thu, 9 Feb 2017 12:14:16 -0800	[thread overview]
Message-ID: <20170209201416.GS2267@bombadil.infradead.org> (raw)
In-Reply-To: <20170126115819.58875-6-kirill.shutemov@linux.intel.com>

On Thu, Jan 26, 2017 at 02:57:47PM +0300, Kirill A. Shutemov wrote:
> @@ -2146,6 +2146,23 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
>  			goto out;
>  		}
>  
> +		/* Try to free buffers before attempt split */
> +		if (!PageSwapBacked(head) && PagePrivate(page)) {
> +			/*
> +			 * We cannot trigger writeback from here due possible
> +			 * recursion if triggered from vmscan, only wait.
> +			 *
> +			 * Caller can trigger writeback it on its own, if safe.
> +			 */

It took me a few reads to get this.  May I suggest:

		/*
		 * Cannot split a page with buffers.  If the caller has
		 * already started writeback, we can wait for it to finish,
		 * but we cannot start writeback if we were called from vmscan
		 */
> +		if (!PageSwapBacked(head) && PagePrivate(page)) {

Also, it looks weird to test PageSwapBacked of *head* and PagePrivate
of *page*.  I think it's correct, but it still looks weird.

Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>

  reply	other threads:[~2017-02-09 20:36 UTC|newest]

Thread overview: 67+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-26 11:57 [PATCHv6 00/37] ext4: support of huge pages Kirill A. Shutemov
2017-01-26 11:57 ` [PATCHv6 01/37] mm, shmem: swich huge tmpfs to multi-order radix-tree entries Kirill A. Shutemov
2017-02-09  3:57   ` Matthew Wilcox
2017-02-09 16:58     ` Kirill A. Shutemov
2017-02-13 13:43       ` Kirill A. Shutemov
2017-01-26 11:57 ` [PATCHv6 02/37] Revert "radix-tree: implement radix_tree_maybe_preload_order()" Kirill A. Shutemov
2017-01-26 15:38   ` Matthew Wilcox
2017-01-26 11:57 ` [PATCHv6 03/37] page-flags: relax page flag policy for few flags Kirill A. Shutemov
2017-02-09  4:01   ` Matthew Wilcox
2017-02-13 13:59     ` Kirill A. Shutemov
2017-01-26 11:57 ` [PATCHv6 04/37] mm, rmap: account file thp pages Kirill A. Shutemov
2017-02-09 20:17   ` Matthew Wilcox
2017-01-26 11:57 ` [PATCHv6 05/37] thp: try to free page's buffers before attempt split Kirill A. Shutemov
2017-02-09 20:14   ` Matthew Wilcox [this message]
2017-02-13 14:32     ` Kirill A. Shutemov
2017-01-26 11:57 ` [PATCHv6 06/37] thp: handle write-protection faults for file THP Kirill A. Shutemov
2017-01-26 15:44   ` Matthew Wilcox
2017-01-26 15:57     ` Kirill A. Shutemov
2017-02-09 20:19   ` Matthew Wilcox
2017-01-26 11:57 ` [PATCHv6 07/37] filemap: allocate huge page in page_cache_read(), if allowed Kirill A. Shutemov
2017-02-09 21:18   ` Matthew Wilcox
2017-02-13 15:17     ` Kirill A. Shutemov
2017-01-26 11:57 ` [PATCHv6 08/37] filemap: handle huge pages in do_generic_file_read() Kirill A. Shutemov
2017-02-09 21:55   ` Matthew Wilcox
2017-02-13 15:33     ` Kirill A. Shutemov
2017-02-13 16:01       ` Matthew Wilcox
2017-02-13 16:09         ` Matthew Wilcox
2017-02-13 16:28   ` Matthew Wilcox
2017-01-26 11:57 ` [PATCHv6 09/37] filemap: allocate huge page in pagecache_get_page(), if allowed Kirill A. Shutemov
2017-02-09 21:59   ` Matthew Wilcox
2017-01-26 11:57 ` [PATCHv6 10/37] filemap: handle huge pages in filemap_fdatawait_range() Kirill A. Shutemov
2017-02-09 23:03   ` Matthew Wilcox
2017-01-26 11:57 ` [PATCHv6 11/37] HACK: readahead: alloc huge pages, if allowed Kirill A. Shutemov
2017-02-09 23:34   ` Matthew Wilcox
2017-02-10  0:23     ` Andreas Dilger
2017-02-10 14:51       ` Matthew Wilcox
2017-01-26 11:57 ` [PATCHv6 12/37] brd: make it handle huge pages Kirill A. Shutemov
2017-02-10 17:24   ` Matthew Wilcox
2017-01-26 11:57 ` [PATCHv6 13/37] mm: make write_cache_pages() work on " Kirill A. Shutemov
2017-02-10 17:46   ` Matthew Wilcox
2017-01-26 11:57 ` [PATCHv6 14/37] thp: introduce hpage_size() and hpage_mask() Kirill A. Shutemov
2017-01-26 11:57 ` [PATCHv6 15/37] thp: do not threat slab pages as huge in hpage_{nr_pages,size,mask} Kirill A. Shutemov
2017-02-10 22:13   ` Matthew Wilcox
2017-01-26 11:57 ` [PATCHv6 16/37] thp: make thp_get_unmapped_area() respect S_HUGE_MODE Kirill A. Shutemov
2017-02-10 17:50   ` Matthew Wilcox
2017-01-26 11:57 ` [PATCHv6 17/37] fs: make block_read_full_page() be able to read huge page Kirill A. Shutemov
2017-02-10 17:58   ` Matthew Wilcox
2017-01-26 11:58 ` [PATCHv6 18/37] fs: make block_write_{begin,end}() be able to handle huge pages Kirill A. Shutemov
2017-01-26 11:58 ` [PATCHv6 19/37] fs: make block_page_mkwrite() aware about " Kirill A. Shutemov
2017-01-26 11:58 ` [PATCHv6 20/37] truncate: make truncate_inode_pages_range() " Kirill A. Shutemov
2017-01-26 11:58 ` [PATCHv6 21/37] truncate: make invalidate_inode_pages2_range() " Kirill A. Shutemov
2017-01-26 11:58 ` [PATCHv6 22/37] mm, hugetlb: switch hugetlbfs to multi-order radix-tree entries Kirill A. Shutemov
2017-01-26 11:58 ` [PATCHv6 23/37] mm: account huge pages to dirty, writaback, reclaimable, etc Kirill A. Shutemov
2017-01-26 11:58 ` [PATCHv6 24/37] ext4: make ext4_mpage_readpages() hugepage-aware Kirill A. Shutemov
2017-01-26 11:58 ` [PATCHv6 25/37] ext4: make ext4_writepage() work on huge pages Kirill A. Shutemov
2017-01-26 11:58 ` [PATCHv6 26/37] ext4: handle huge pages in ext4_page_mkwrite() Kirill A. Shutemov
2017-01-26 11:58 ` [PATCHv6 27/37] ext4: handle huge pages in __ext4_block_zero_page_range() Kirill A. Shutemov
2017-01-26 11:58 ` [PATCHv6 28/37] ext4: make ext4_block_write_begin() aware about huge pages Kirill A. Shutemov
2017-01-26 11:58 ` [PATCHv6 29/37] ext4: handle huge pages in ext4_da_write_end() Kirill A. Shutemov
2017-01-26 11:58 ` [PATCHv6 30/37] ext4: make ext4_da_page_release_reservation() aware about huge pages Kirill A. Shutemov
2017-01-26 11:58 ` [PATCHv6 31/37] ext4: handle writeback with " Kirill A. Shutemov
2017-01-26 11:58 ` [PATCHv6 32/37] ext4: make EXT4_IOC_MOVE_EXT work " Kirill A. Shutemov
2017-01-26 11:58 ` [PATCHv6 33/37] ext4: fix SEEK_DATA/SEEK_HOLE for " Kirill A. Shutemov
2017-01-26 11:58 ` [PATCHv6 34/37] ext4: make fallocate() operations work with " Kirill A. Shutemov
2017-01-26 11:58 ` [PATCHv6 35/37] ext4: reserve larger jounral transaction for " Kirill A. Shutemov
2017-01-26 11:58 ` [PATCHv6 36/37] mm, fs, ext4: expand use of page_mapping() and page_to_pgoff() Kirill A. Shutemov
2017-01-26 11:58 ` [PATCHv6 37/37] ext4, vfs: add huge= mount option Kirill A. Shutemov

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