• Chris Wilson's avatar
    drm/i915: Report all objects with allocated pages to the shrinker · d82b4b26
    Chris Wilson authored
    Currently, we try to report to the shrinker the precise number of
    objects (pages) that are available to be reaped at this moment. This
    requires searching all objects with allocated pages to see if they
    fulfill the search criteria, and this count is performed quite
    frequently. (The shrinker tries to free ~128 pages on each invocation,
    before which we count all the objects; counting takes longer than
    unbinding the objects!) If we take the pragmatic view that with
    sufficient desire, all objects are eventually reapable (they become
    inactive, or no longer used as framebuffer etc), we can simply return
    the count of pinned pages maintained during get_pages/put_pages rather
    than walk the lists every time.
    
    The downside is that we may (slightly) over-report the number of
    objects/pages we could shrink and so penalize ourselves by shrinking
    more than required. This is mitigated by keeping the order in which we
    shrink objects such that we avoid penalizing active and frequently used
    objects, and if memory is so tight that we need to free them we would
    need to anyway.
    
    v2: Only expose shrinkable objects to the shrinker; a small reduction in
    not considering stolen and foreign objects.
    v3: Restore the tracking from a "backup" copy from before the gem/ split
    Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
    Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
    Cc: Matthew Auld <matthew.auld@intel.com>
    Reviewed-by: default avatarMatthew Auld <matthew.auld@intel.com>
    Link: https://patchwork.freedesktop.org/patch/msgid/20190530203500.26272-2-chris@chris-wilson.co.uk
    d82b4b26
i915_gem_object.c 12.1 KB