Limit the commit size to 1/8 dirty control scope, so that the arrival of one commit will not knock the overall dirty pages off the scope. CC: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx> Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx> --- fs/nfs/write.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) After patch, there are still drop offs from the control scope, http://www.kernel.org/pub/linux/kernel/people/wfg/writeback/dirty-throttling-v6/NFS/nfs-1dd-1M-8p-2945M-20%25-2.6.38-rc6-dt6+-2011-02-22-21-09/balance_dirty_pages-pages.png due to bursty arrival of commits: http://www.kernel.org/pub/linux/kernel/people/wfg/writeback/dirty-throttling-v6/NFS/nfs-1dd-1M-8p-2945M-20%25-2.6.38-rc6-dt6+-2011-02-22-21-09/nfs-commit.png --- linux-next.orig/fs/nfs/write.c 2011-03-02 20:39:01.000000000 +0800 +++ linux-next/fs/nfs/write.c 2011-03-02 20:39:01.000000000 +0800 @@ -1492,9 +1492,10 @@ static int nfs_commit_unstable_pages(str if (wbc->sync_mode == WB_SYNC_NONE) { /* Don't commit yet if this is a non-blocking flush and there - * are a lot of outstanding writes for this mapping. + * are a lot of outstanding writes for this mapping, until + * collected enough pages to commit. */ - if (nfsi->ncommit <= (nfsi->npages >> 1)) + if (nfsi->ncommit <= nfsi->npages / 32 /* DIRTY_MARGIN */) goto out_mark_dirty; /* don't wait for the COMMIT response */ -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
