On Fri, May 24, 2013 at 03:59:14PM +0530, Glauber Costa wrote:
> The main shrinker driver will keep trying for a while to free objects if
> the returned value from the shrink scan procedure is 0. That means "no
> objects now", but a retry could very well succeed.
>
> A negative value has a different meaning. It means it is impossible to
> shrink, and we would better bail out soon. We find this behavior more
> appropriate for the case where the lock cannot be taken. Specially given
> the hammer behavior of the i915: if another thread is already shrinking,
> we are likely not to be able to shrink anything anyway when we finally
> acquire the mutex.
>
> Signed-off-by: Glauber Costa <glommer@xxxxxxxxxx>
> CC: Dave Chinner <dchinner@xxxxxxxxxx>
> CC: Mel Gorman <mgorman@xxxxxxx>
> CC: Daniel Vetter <daniel.vetter@xxxxxxxx>
> CC: Kent Overstreet <koverstreet@xxxxxxxxxx>
Acked-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_gem.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 6b17122..52b3ac1 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -4448,10 +4448,10 @@ i915_gem_inactive_count(struct shrinker *shrinker, struct shrink_control *sc)
>
> if (!mutex_trylock(&dev->struct_mutex)) {
> if (!mutex_is_locked_by(&dev->struct_mutex, current))
> - return 0;
> + return -1;
>
> if (dev_priv->mm.shrinker_no_lock_stealing)
> - return 0;
> + return -1;
>
> unlock = false;
> }
> --
> 1.8.1.4
>
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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