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authorNeilBrown <neilb@suse.de>2014-09-24 11:28:32 +1000
committerTrond Myklebust <trond.myklebust@primarydata.com>2014-09-25 08:25:38 -0400
commit353db7966288a2f18da22438aeec2b4862c0b241 (patch)
tree959b0fe5a246747af6db55bb7652d4d35b738ba8 /fs/nfs/write.c
parent9590544694becc64f4874963dbfc4b4d391024b7 (diff)
NFS: avoid waiting at all in nfs_release_page when congested.
If nfs_release_page() is called on a sequence of pages which are all in the same file which is blocked on COMMIT, each page could contribute a 1 second delay which could be come excessive. I have seen delays of as much as 208 seconds. To keep the delay to one second, mark the bdi as write-congested if the commit didn't finished. Once it does finish, the write-congested flag will be cleared by nfs_commit_release_pages(). With this, the longest total delay in try_to_free_pages that I have seen is under 3 seconds. With no waiting in nfs_release_page at all I have seen delays of nearly 1.5 seconds. Signed-off-by: NeilBrown <neilb@suse.de> Acked-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Diffstat (limited to 'fs/nfs/write.c')
-rw-r--r--fs/nfs/write.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index c063a4e70354..12493846a2d3 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -1611,6 +1611,7 @@ static void nfs_commit_release_pages(struct nfs_commit_data *data)
struct nfs_page *req;
int status = data->task.tk_status;
struct nfs_commit_info cinfo;
+ struct nfs_server *nfss;
while (!list_empty(&data->pages)) {
req = nfs_list_entry(data->pages.next);
@@ -1644,6 +1645,10 @@ static void nfs_commit_release_pages(struct nfs_commit_data *data)
next:
nfs_unlock_and_release_request(req);
}
+ nfss = NFS_SERVER(data->inode);
+ if (atomic_long_read(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
+ clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC);
+
nfs_init_cinfo(&cinfo, data->inode, data->dreq);
if (atomic_dec_and_test(&cinfo.mds->rpcs_out))
nfs_commit_clear_lock(NFS_I(data->inode));