| Message ID | 20210401012722.527712-1-robdclark@gmail.com |
|---|---|
| Headers | show |
| Series | drm/msm: Shrinker (and related) fixes | expand |
Hi, On Wed, Mar 31, 2021 at 6:24 PM Rob Clark <robdclark@gmail.com> wrote: > > @@ -45,6 +30,9 @@ msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc) > list_for_each_entry(msm_obj, &priv->inactive_dontneed, mm_list) { > if (freed >= sc->nr_to_scan) > break; > + /* Use trylock, because we cannot block on a obj that > + * might be trying to acquire mm_lock > + */ nit: I thought the above multi-line commenting style was only for "net" subsystem? > if (!msm_gem_trylock(&msm_obj->base)) > continue; > if (is_purgeable(msm_obj)) { > @@ -56,8 +44,11 @@ msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc) > > mutex_unlock(&priv->mm_lock); > > - if (freed > 0) > + if (freed > 0) { > trace_msm_gem_purge(freed << PAGE_SHIFT); > + } else { > + return SHRINK_STOP; > + } It probably doesn't matter, but I wonder if we should still be returning SHRINK_STOP if we got any trylock failures. It could possibly be worth returning 0 in that case? > @@ -75,6 +66,9 @@ vmap_shrink(struct list_head *mm_list) > unsigned unmapped = 0; > > list_for_each_entry(msm_obj, mm_list, mm_list) { > + /* Use trylock, because we cannot block on a obj that > + * might be trying to acquire mm_lock > + */ If you end up changing the commenting style above, should also be here. At this point this seems fine to land to me. Though I'm not an expert on every interaction in this code, I've spent enough time starting at it that I'm comfortable with: Reviewed-by: Douglas Anderson <dianders@chromium.org>
From: Rob Clark <robdclark@chromium.org> I've been spending some time looking into how things behave under high memory pressure. The first patch is a random cleanup I noticed along the way. The second improves the situation significantly when we are getting shrinker called from many threads in parallel. And the last two are $debugfs/gem fixes I needed so I could monitor the state of GEM objects (ie. how many are active/purgable/purged) while triggering high memory pressure. We could probably go a bit further with dropping the mm_lock in the shrinker->scan() loop, but this is already a pretty big improvement. The next step is probably actually to add support to unpin/evict inactive objects. (We are part way there since we have already de- coupled the iova lifetime from the pages lifetime, but there are a few sharp corners to work through.) Rob Clark (4): drm/msm: Remove unused freed llist node drm/msm: Avoid mutex in shrinker_count() drm/msm: Fix debugfs deadlock drm/msm: Improved debugfs gem stats drivers/gpu/drm/msm/msm_debugfs.c | 14 ++--- drivers/gpu/drm/msm/msm_drv.c | 4 ++ drivers/gpu/drm/msm/msm_drv.h | 15 ++++-- drivers/gpu/drm/msm/msm_fb.c | 3 +- drivers/gpu/drm/msm/msm_gem.c | 65 ++++++++++++++++++----- drivers/gpu/drm/msm/msm_gem.h | 72 +++++++++++++++++++++++--- drivers/gpu/drm/msm/msm_gem_shrinker.c | 28 ++++------ 7 files changed, 150 insertions(+), 51 deletions(-)