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47 lines
1.7 KiB
47 lines
1.7 KiB
From: Mel Gorman <mgorman@suse.de>
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Date: Wed, 9 Mar 2011 12:26:23 +0000
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Subject: [PATCH] netvm: Do not mark requests for swapfile writes as dirty or kswapd fails to free the page
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Patch-mainline: Not yet
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References: bnc#678472
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When writing back NFS pages from kswapd, the inode and pages are getting
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marked dirty before IO has even started. The expectation of kswapd is
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that it calls clear_page_dirty_for_io(), submits IO and the filesystem
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remarks the page dirty if necessary. Without this patch, the page always
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comes back under writeback and still dirty. kswapd continually launders
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but never frees leading to deadlock.
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Signed-off-by: Mel Gorman <mgorman@suse.de>
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---
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fs/nfs/write.c | 14 ++++++++++++--
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1 files changed, 12 insertions(+), 2 deletions(-)
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diff --git a/fs/nfs/write.c b/fs/nfs/write.c
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index 2375c7d..fe05d78 100644
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--- a/fs/nfs/write.c
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+++ b/fs/nfs/write.c
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@@ -744,11 +744,21 @@ static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
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req = nfs_setup_write_request(ctx, page, offset, count);
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if (IS_ERR(req))
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return PTR_ERR(req);
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- nfs_mark_request_dirty(req);
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+
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+ /*
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+ * There is no need to mark swapfile requests as dirty like normal
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+ * writepage requests as page dirtying and cleaning is managed
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+ * from the mm. If a PageSwapCache page is marked dirty like this,
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+ * it will still be dirty after kswapd calls writepage and may
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+ * never be released
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+ */
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+ if (!PageSwapCache(page))
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+ nfs_mark_request_dirty(req);
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/* Update file length */
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nfs_grow_file(page, offset, count);
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nfs_mark_uptodate(page, req->wb_pgbase, req->wb_bytes);
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- nfs_mark_request_dirty(req);
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+ if (!PageSwapCache(page))
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+ nfs_mark_request_dirty(req);
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nfs_clear_page_tag_locked(req);
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return 0;
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}
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