• SeongJae Park's avatar
    mm/damon/sysfs-schemes: do not update tried regions more than one DAMON snapshot · 4d4e41b6
    SeongJae Park authored
    Patch series "mm/damon/sysfs-schemes: Do DAMOS tried regions update for
    only one apply interval".
    
    DAMOS tried regions update feature of DAMON sysfs interface is doing the
    update for one aggregation interval after the request is made.  Since the
    per-scheme apply interval is supported, that behavior makes no much sense.
    That is, the tried regions directory will have regions from multiple
    DAMON monitoring results snapshots, or no region for apply intervals that
    much shorter than, or longer than the aggregation interval, respectively. 
    Update the behavior to update the regions for each scheme for only its
    apply interval, and update the document.
    
    Since DAMOS apply interval is the aggregation by default, this change
    makes no visible behavioral difference to old users who don't explicitly
    set the apply intervals.
    
    Patches Sequence
    ----------------
    
    The first two patches makes schemes of apply intervals that much shorter
    or longer than the aggregation interval to keep the maximum and minimum
    times for continuing the update.  After the two patches, the update aligns
    with the each scheme's apply interval.
    
    Finally, the third patch updates the document to reflect the behavior.
    
    
    This patch (of 3):
    
    DAMON_SYSFS exposes every DAMON-found region that eligible for applying
    the scheme action for one aggregation interval.  However, each DAMON-based
    operation scheme has its own apply interval.  Hence, for a scheme that
    having its apply interval much smaller than the aggregation interval,
    DAMON_SYSFS will expose the scheme regions that applied to more than one
    DAMON monitoring results snapshots.  Since the purpose of DAMON tried
    regions is exposing single snapshot, this makes no much sense.  Track
    progress of each scheme's tried regions update and avoid the case.
    
    Link: https://lkml.kernel.org/r/20231012192256.33556-1-sj@kernel.org
    Link: https://lkml.kernel.org/r/20231012192256.33556-2-sj@kernel.orgSigned-off-by: default avatarSeongJae Park <sj@kernel.org>
    Cc: Jonathan Corbet <corbet@lwn.net>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    4d4e41b6
sysfs-schemes.c 51.4 KB