Eric Lee / smarc-fsl-linux-kernel

06 Dec, 2007

1 commit

17 Oct, 2007

3 commits

  • 04fbfdc14   mm: per device dirty threshold ... Browse Code »

    Scale writeback cache per backing device, proportional to its writeout speed.

    By decoupling the BDI dirty thresholds a number of problems we currently have
    will go away, namely:

    - mutual interference starvation (for any number of BDIs);
    - deadlocks with stacked BDIs (loop, FUSE and local NFS mounts).

    It might be that all dirty pages are for a single BDI while other BDIs are
    idling. By giving each BDI a 'fair' share of the dirty limit, each one can have
    dirty pages outstanding and make progress.

    A global threshold also creates a deadlock for stacked BDIs; when A writes to
    B, and A generates enough dirty pages to get throttled, B will never start
    writeback until the dirty pages go away. Again, by giving each BDI its own
    'independent' dirty limit, this problem is avoided.

    So the problem is to determine how to distribute the total dirty limit across
    the BDIs fairly and efficiently. A DBI that has a large dirty limit but does
    not have any dirty pages outstanding is a waste.

    What is done is to keep a floating proportion between the DBIs based on
    writeback completions. This way faster/more active devices get a larger share
    than slower/idle devices.

    [akpm@linux-foundation.org: fix warnings]
    [hugh@veritas.com: Fix occasional hang when a task couldn't get out of balance_dirty_pages]
    Signed-off-by: Peter Zijlstra
    Signed-off-by: Hugh Dickins
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Peter Zijlstra
     
  • b2e8fb6ef   mm: scalable bdi statistics counters ... Browse Code »

    Provide scalable per backing_dev_info statistics counters.

    Signed-off-by: Peter Zijlstra
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Peter Zijlstra
     
  • c4dc4beed   nfs: remove congestion_end() ... Browse Code »

    These patches aim to improve balance_dirty_pages() and directly address three
    issues:
    1) inter device starvation
    2) stacked device deadlocks
    3) inter process starvation

    1 and 2 are a direct result from removing the global dirty limit and using
    per device dirty limits. By giving each device its own dirty limit is will
    no longer starve another device, and the cyclic dependancy on the dirty limit
    is broken.

    In order to efficiently distribute the dirty limit across the independant
    devices a floating proportion is used, this will allocate a share of the total
    limit proportional to the device's recent activity.

    3 is done by also scaling the dirty limit proportional to the current task's
    recent dirty rate.

    This patch:

    nfs: remove congestion_end(). It's redundant, clear_bdi_congested() already
    wakes the waiters.

    Signed-off-by: Peter Zijlstra
    Cc: Trond Myklebust
    Cc: "J. Bruce Fields"
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Peter Zijlstra
     

17 Jul, 2007

1 commit

17 Mar, 2007

1 commit

  • 89a09141d   [PATCH] nfs: fix congestion control ... Browse Code »

    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
    Acked-by: Trond Myklebust
    Cc: Christoph Lameter
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Peter Zijlstra
     

21 Oct, 2006

1 commit

  • 3fcfab16c   [PATCH] separate bdi congestion functions from queue congestion functions ... Browse Code »

    Separate out the concept of "queue congestion" from "backing-dev congestion".
    Congestion is a backing-dev concept, not a queue concept.

    The blk_* congestion functions are retained, as wrappers around the core
    backing-dev congestion functions.

    This proper layering is needed so that NFS can cleanly use the congestion
    functions, and so that CONFIG_BLOCK=n actually links.

    Cc: "Thomas Maier"
    Cc: "Jens Axboe"
    Cc: Trond Myklebust
    Cc: David Howells
    Cc: Peter Osterlund
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Andrew Morton