Commit 192e501b authored Jul 31, 2012 by Mel Gorman Committed by Linus Torvalds Jul 31, 2012

nfs: prevent page allocator recursions with swap over NFS.



GFP_NOFS is _more_ permissive than GFP_NOIO in that it will initiate IO,
just not of any filesystem data.

The problem is that previously NOFS was correct because that avoids
recursion into the NFS code.  With swap-over-NFS, it is no longer correct
as swap IO can lead to this recursion.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Eric Paris <eparis@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Neil Brown <neilb@suse.de>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Xiaotian Feng <dfeng@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent a564b8f0

fs/nfs/pagelist.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -70,7 +70,7 @@ void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t pos)
		static inline struct nfs_page *
		nfs_page_alloc(void)
		{
		struct nfs_page *p = kmem_cache_zalloc(nfs_page_cachep, GFP_KERNEL);
		struct nfs_page *p = kmem_cache_zalloc(nfs_page_cachep, GFP_NOIO);
		if (p)
		INIT_LIST_HEAD(&p->wb_list);
		return p;

fs/nfs/write.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -52,7 +52,7 @@ static mempool_t *nfs_commit_mempool;

		struct nfs_commit_data *nfs_commitdata_alloc(void)
		{
		struct nfs_commit_data *p = mempool_alloc(nfs_commit_mempool, GFP_NOFS);
		struct nfs_commit_data *p = mempool_alloc(nfs_commit_mempool, GFP_NOIO);

		if (p) {
		memset(p, 0, sizeof(*p));
		@@ -70,7 +70,7 @@ EXPORT_SYMBOL_GPL(nfs_commit_free);

		struct nfs_write_header *nfs_writehdr_alloc(void)
		{
		struct nfs_write_header *p = mempool_alloc(nfs_wdata_mempool, GFP_NOFS);
		struct nfs_write_header *p = mempool_alloc(nfs_wdata_mempool, GFP_NOIO);

		if (p) {
		struct nfs_pgio_header *hdr = &p->header;

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