From: Rob Clark <robdcl...@chromium.org>

If we are under enough memory pressure, we should stall waiting for
active buffers to become idle in order to evict.

v2: Check for __GFP_ATOMIC before blocking

Signed-off-by: Rob Clark <robdcl...@chromium.org>
---
 drivers/gpu/drm/msm/msm_gem_shrinker.c | 70 +++++++++++++++++++++-----
 drivers/gpu/drm/msm/msm_gpu_trace.h    | 16 +++---
 2 files changed, 68 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_gem_shrinker.c 
b/drivers/gpu/drm/msm/msm_gem_shrinker.c
index 5cc05d669a08..f31054d25314 100644
--- a/drivers/gpu/drm/msm/msm_gem_shrinker.c
+++ b/drivers/gpu/drm/msm/msm_gem_shrinker.c
@@ -24,6 +24,13 @@ static bool can_swap(void)
        return enable_eviction && get_nr_swap_pages() > 0;
 }
 
+static bool can_block(struct shrink_control *sc)
+{
+       if (sc->gfp_mask & __GFP_ATOMIC)
+               return false;
+       return current_is_kswapd() || (sc->gfp_mask & __GFP_RECLAIM);
+}
+
 static unsigned long
 msm_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
 {
@@ -65,26 +72,65 @@ evict(struct drm_gem_object *obj)
        return true;
 }
 
+static bool
+wait_for_idle(struct drm_gem_object *obj)
+{
+       enum dma_resv_usage usage = dma_resv_usage_rw(true);
+       return dma_resv_wait_timeout(obj->resv, usage, false, 1000) > 0;
+}
+
+static bool
+active_purge(struct drm_gem_object *obj)
+{
+       if (!wait_for_idle(obj))
+               return false;
+
+       return purge(obj);
+}
+
+static bool
+active_evict(struct drm_gem_object *obj)
+{
+       if (!wait_for_idle(obj))
+               return false;
+
+       return evict(obj);
+}
+
 static unsigned long
 msm_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
 {
        struct msm_drm_private *priv =
                container_of(shrinker, struct msm_drm_private, shrinker);
+       struct {
+               struct drm_gem_lru *lru;
+               bool (*shrink)(struct drm_gem_object *obj);
+               bool cond;
+               unsigned long freed;
+       } stages[] = {
+               /* Stages of progressively more aggressive/expensive reclaim: */
+               { &priv->lru.dontneed, purge,        true },
+               { &priv->lru.willneed, evict,        can_swap() },
+               { &priv->lru.dontneed, active_purge, can_block(sc) },
+               { &priv->lru.willneed, active_evict, can_swap() && 
can_block(sc) },
+       };
        long nr = sc->nr_to_scan;
-       unsigned long freed, purged, evicted = 0;
-
-       purged = drm_gem_lru_scan(&priv->lru.dontneed, nr, purge);
-       nr -= purged;
-
-       if (can_swap() && nr > 0) {
-               evicted = drm_gem_lru_scan(&priv->lru.willneed, nr, evict);
-               nr -= evicted;
+       unsigned long freed = 0;
+
+       for (unsigned i = 0; (nr > 0) && (i < ARRAY_SIZE(stages)); i++) {
+               if (!stages[i].cond)
+                       continue;
+               stages[i].freed =
+                       drm_gem_lru_scan(stages[i].lru, nr, stages[i].shrink);
+               nr -= stages[i].freed;
+               freed += stages[i].freed;
        }
 
-       freed = purged + evicted;
-
-       if (freed)
-               trace_msm_gem_shrink(sc->nr_to_scan, purged, evicted);
+       if (freed) {
+               trace_msm_gem_shrink(sc->nr_to_scan, stages[0].freed,
+                                    stages[1].freed, stages[2].freed,
+                                    stages[3].freed);
+       }
 
        return (freed > 0) ? freed : SHRINK_STOP;
 }
diff --git a/drivers/gpu/drm/msm/msm_gpu_trace.h 
b/drivers/gpu/drm/msm/msm_gpu_trace.h
index 8867fa0a0306..ac40d857bc45 100644
--- a/drivers/gpu/drm/msm/msm_gpu_trace.h
+++ b/drivers/gpu/drm/msm/msm_gpu_trace.h
@@ -116,22 +116,26 @@ TRACE_EVENT(msm_gmu_freq_change,
 
 
 TRACE_EVENT(msm_gem_shrink,
-               TP_PROTO(u32 nr_to_scan, u32 purged, u32 evicted),
-               TP_ARGS(nr_to_scan, purged, evicted),
+               TP_PROTO(u32 nr_to_scan, u32 purged, u32 evicted,
+                        u32 active_purged, u32 active_evicted),
+               TP_ARGS(nr_to_scan, purged, evicted, active_purged, 
active_evicted),
                TP_STRUCT__entry(
                        __field(u32, nr_to_scan)
                        __field(u32, purged)
                        __field(u32, evicted)
+                       __field(u32, active_purged)
+                       __field(u32, active_evicted)
                        ),
                TP_fast_assign(
                        __entry->nr_to_scan = nr_to_scan;
                        __entry->purged = purged;
                        __entry->evicted = evicted;
+                       __entry->active_purged = active_purged;
+                       __entry->active_evicted = active_evicted;
                        ),
-               TP_printk("nr_to_scan=%u pages, purged=%u pages, evicted=%u 
pages",
-                         __entry->nr_to_scan,
-                         __entry->purged,
-                         __entry->evicted)
+               TP_printk("nr_to_scan=%u pg, purged=%u pg, evicted=%u pg, 
active_purged=%u pg, active_evicted=%u pg",
+                         __entry->nr_to_scan, __entry->purged, 
__entry->evicted,
+                         __entry->active_purged, __entry->active_evicted)
 );
 
 
-- 
2.36.1

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