lkml.org 
[lkml]   [2019]   [Dec]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Subject[PATCH v13 0/5] xenbus/backend: Add memory pressure handler callback
    Date
    Granting pages consumes backend system memory.  In systems configured
    with insufficient spare memory for those pages, it can cause a memory
    pressure situation. However, finding the optimal amount of the spare
    memory is challenging for large systems having dynamic resource
    utilization patterns. Also, such a static configuration might lack
    flexibility.

    To mitigate such problems, this patchset adds a memory reclaim callback
    to 'xenbus_driver' (patch 1) and then introduce a lock for race
    condition avoidance (patch 2). After that, patch 3 applies the callback
    mechanism to mitigate the problem in 'xen-blkback'. The fourth and
    fifth patches are trivial cleanups; those fix nits we found during the
    development of this patchset.

    Note that patches 1, 4, and 5 are not changed since v9.


    Base Version
    ------------

    This patch is based on v5.4. A complete tree is also available at my
    public git repo:
    https://github.com/sjp38/linux/tree/patches/blkback/buffer_squeeze/v13


    Patch History
    -------------

    Changes from v12
    (https://lore.kernel.org/xen-devel/20191218104232.9606-1-sjpark@amazon.com/)
    - Do not unnecessarily disable interrupts (suggested by Juergen)
    - Hold lock from xenbus side (suggested by Juergen)

    Changes from v11
    (https://lore.kernel.org/xen-devel/20191217160748.693-2-sjpark@amazon.com/)
    - Fix wrong trylock use (reported by Juergen)
    - Merge patch 3 and 4 (suggested by Juergen)
    - Update test result

    Changes from v10
    (https://lore.kernel.org/xen-devel/20191216124527.30306-1-sjpark@amazon.com/)
    - Fix race condition (reported by SeongJae, suggested by Juergen)

    Changes from v9
    (https://lore.kernel.org/xen-devel/20191213153546.17425-1-sjpark@amazon.de/)
    - Add 'Reviewed-by' and 'Acked-by' from Roger Pau Monné
    - Update the commit message for overhead test of the 2nd path

    Changes from v8
    (https://lore.kernel.org/xen-devel/20191213130211.24011-1-sjpark@amazon.de/)
    - Drop 'Reviewed-by: Juergen' from the second patch
    (suggested by Roger Pau Monné)
    - Update contact of the new module param to SeongJae Park
    <sjpark@amazon.de>
    (suggested by Roger Pau Monné)
    - Wordsmith the description of the parameter
    (suggested by Roger Pau Monné)
    - Fix dumb bugs
    (suggested by Roger Pau Monné)
    - Move module param definition to xenbus.c and reduce the number of
    lines for this change
    (suggested by Roger Pau Monné)
    - Add a comment for the new callback, reclaim_memory, as other
    callbacks also have
    - Add another trivial cleanup of xenbus.c file (4th patch)

    Changes from v7
    (https://lore.kernel.org/xen-devel/20191211181016.14366-1-sjpark@amazon.de/)
    - Update sysfs-driver-xen-blkback for new parameter
    (suggested by Roger Pau Monné)
    - Use per-xen_blkif buffer_squeeze_end instead of global variable
    (suggested by Roger Pau Monné)

    Changes from v6
    (https://lore.kernel.org/linux-block/20191211042428.5961-1-sjpark@amazon.de/)
    - Remove more unnecessary prefixes (suggested by Roger Pau Monné)
    - Constify a variable (suggested by Roger Pau Monné)
    - Rename 'reclaim' into 'reclaim_memory' (suggested by Roger Pau Monné)
    - More wordsmith of the commit message (suggested by Roger Pau Monné)

    Changes from v5
    (https://lore.kernel.org/linux-block/20191210080628.5264-1-sjpark@amazon.de/)
    - Wordsmith the commit messages (suggested by Roger Pau Monné)
    - Change the reclaim callback return type (suggested by Roger Pau
    Monné)
    - Change the type of the blkback squeeze duration variable
    (suggested by Roger Pau Monné)
    - Add a patch for removal of unnecessary static variable name prefixes
    (suggested by Roger Pau Monné)
    - Fix checkpatch.pl warnings

    Changes from v4
    (https://lore.kernel.org/xen-devel/20191209194305.20828-1-sjpark@amazon.com/)
    - Remove domain id parameter from the callback (suggested by Juergen
    Gross)
    - Rename xen-blkback module parameter (suggested by Stefan Nuernburger)

    Changes from v3
    (https://lore.kernel.org/xen-devel/20191209085839.21215-1-sjpark@amazon.com/)
    - Add general callback in xen_driver and use it (suggested by Juergen
    Gross)

    Changes from v2
    (https://lore.kernel.org/linux-block/af195033-23d5-38ed-b73b-f6e2e3b34541@amazon.com)
    - Rename the module parameter and variables for brevity
    (aggressive shrinking -> squeezing)

    Changes from v1
    (https://lore.kernel.org/xen-devel/20191204113419.2298-1-sjpark@amazon.com/)
    - Adjust the description to not use the term, `arbitrarily`
    (suggested by Paul Durrant)
    - Specify time unit of the duration in the parameter description,
    (suggested by Maximilian Heyne)
    - Change default aggressive shrinking duration from 1ms to 10ms
    - Merge two patches into one single patch


    SeongJae Park (5):
    xenbus/backend: Add memory pressure handler callback
    xenbus/backend: Protect xenbus callback with lock
    xen/blkback: Squeeze page pools if a memory pressure is detected
    xen/blkback: Remove unnecessary static variable name prefixes
    xen/blkback: Consistently insert one empty line between functions

    .../ABI/testing/sysfs-driver-xen-blkback | 10 +++++
    drivers/block/xen-blkback/blkback.c | 42 +++++++++----------
    drivers/block/xen-blkback/common.h | 1 +
    drivers/block/xen-blkback/xenbus.c | 28 ++++++++++---
    drivers/xen/xenbus/xenbus_probe.c | 8 +++-
    drivers/xen/xenbus/xenbus_probe_backend.c | 38 +++++++++++++++++
    include/xen/xenbus.h | 3 ++
    7 files changed, 103 insertions(+), 27 deletions(-)

    --
    2.17.1

    \
     
     \ /
      Last update: 2019-12-18 19:39    [W:2.296 / U:0.004 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site