lkml.org 
[lkml]   [2010]   [Dec]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[PATCH 33/35] nfs: adapt congestion threshold to dirty threshold
    nfs_congestion_kb is to control the max allowed writeback and in-commit
    pages. It's not reasonable for them to outnumber dirty and to-commit
    pages. So each of them should not take more than 1/4 dirty threshold.

    Considering that nfs_init_writepagecache() is called on fresh boot,
    at the time dirty_thresh is much higher than the real dirty limit after
    lots of user space memory consumptions, use 1/8 instead.

    We might update nfs_congestion_kb when global dirty limit is changed
    at runtime, but whatever, do it simple first.

    CC: Trond Myklebust <Trond.Myklebust@netapp.com>
    Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
    ---
    fs/nfs/write.c | 13 +++++++++++++
    1 file changed, 13 insertions(+)

    --- linux-next.orig/fs/nfs/write.c 2010-12-13 21:46:22.000000000 +0800
    +++ linux-next/fs/nfs/write.c 2010-12-13 21:46:22.000000000 +0800
    @@ -1698,6 +1698,9 @@ out:

    int __init nfs_init_writepagecache(void)
    {
    + unsigned long background_thresh;
    + unsigned long dirty_thresh;
    +
    nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
    sizeof(struct nfs_write_data),
    0, SLAB_HWCACHE_ALIGN,
    @@ -1735,6 +1738,16 @@ int __init nfs_init_writepagecache(void)
    if (nfs_congestion_kb > 256*1024)
    nfs_congestion_kb = 256*1024;

    + /*
    + * Limit to 1/8 dirty threshold, so that writeback+in_commit pages
    + * won't overnumber dirty+to_commit pages.
    + */
    + global_dirty_limits(&background_thresh, &dirty_thresh);
    + dirty_thresh <<= PAGE_SHIFT - 10;
    +
    + if (nfs_congestion_kb > dirty_thresh / 8)
    + nfs_congestion_kb = dirty_thresh / 8;
    +
    return 0;
    }




    \
     
     \ /
      Last update: 2010-12-13 16:39    [W:2.824 / U:0.360 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site