[PATCH] nfs: fix congestion control
The current NFS client congestion logic is severly broken, it marks the
backing device congested during each nfs_writepages() call but doesn't
mirror this in nfs_writepage() which makes for deadlocks. Also it
implements its own waitqueue.
Replace this by a more regular congestion implementation that puts a cap on
the number of active writeback pages and uses the bdi congestion waitqueue.
Also always use an interruptible wait since it makes sense to be able to
SIGKILL the process even for mounts without 'intr'.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 47aaa2c..e9ae0c6 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -415,6 +415,7 @@
/*
* linux/fs/nfs/write.c
*/
+extern int nfs_congestion_kb;
extern int nfs_writepage(struct page *page, struct writeback_control *wbc);
extern int nfs_writepages(struct address_space *, struct writeback_control *);
extern int nfs_flush_incompatible(struct file *file, struct page *page);