[PATCH 29/38] drm/i915: Wire up shrinkctl->nr_scanned
Chris Wilson
chris at chris-wilson.co.uk
Wed Sep 13 13:02:32 UTC 2017
shrink_slab() allows us to report back the number of objects we
successfully scanned (out of the target shrinkctl->nr_to_scan). As
report the number of pages owned by each GEM object as a separate item
to the shrinker, we cannot precisely control the number of shrinker
objects we scan on each pass; and indeed may free more than requested.
If we fail to tell the shrinker about the number of objects we process,
it will continue to hold a grudge against us as any objects left
unscanned are added to the next reclaim -- and so we will keep on
"unfairly" shrinking our own slab in comparison to other slabs.
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: Andrew Morton <akpm at linux-foundation.org>
Cc: Michal Hocko <mhocko at suse.com>
Cc: Johannes Weiner <hannes at cmpxchg.org>
Cc: Hillf Danton <hillf.zj at alibaba-inc.com>
Cc: Minchan Kim <minchan at kernel.org>
Cc: Vlastimil Babka <vbabka at suse.cz>
Cc: Mel Gorman <mgorman at techsingularity.net>
Cc: Shaohua Li <shli at fb.com>
Cc: linux-mm at kvack.org
---
drivers/gpu/drm/i915/i915_debugfs.c | 4 ++--
drivers/gpu/drm/i915/i915_drv.h | 1 +
drivers/gpu/drm/i915/i915_gem.c | 4 ++--
drivers/gpu/drm/i915/i915_gem_gtt.c | 2 +-
drivers/gpu/drm/i915/i915_gem_shrinker.c | 26 +++++++++++++++++++-------
5 files changed, 25 insertions(+), 12 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 9a2b60590b4b..84d2dc02e762 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -4398,10 +4398,10 @@ i915_drop_caches_set(void *data, u64 val)
lockdep_set_current_reclaim_state(GFP_KERNEL);
if (val & DROP_BOUND)
- i915_gem_shrink(dev_priv, LONG_MAX, I915_SHRINK_BOUND);
+ i915_gem_shrink(dev_priv, LONG_MAX, NULL, I915_SHRINK_BOUND);
if (val & DROP_UNBOUND)
- i915_gem_shrink(dev_priv, LONG_MAX, I915_SHRINK_UNBOUND);
+ i915_gem_shrink(dev_priv, LONG_MAX, NULL, I915_SHRINK_UNBOUND);
if (val & DROP_SHRINK_ALL)
i915_gem_shrink_all(dev_priv);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index d6e74a3df2d0..c569e2bcbdf1 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -3832,6 +3832,7 @@ i915_gem_object_create_internal(struct drm_i915_private *dev_priv,
/* i915_gem_shrinker.c */
unsigned long i915_gem_shrink(struct drm_i915_private *dev_priv,
unsigned long target,
+ unsigned long *nr_scanned,
unsigned flags);
#define I915_SHRINK_PURGEABLE 0x1
#define I915_SHRINK_UNBOUND 0x2
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 718d589fd02b..3e16e2141f45 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2366,7 +2366,7 @@ i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj)
goto err_sg;
}
- i915_gem_shrink(dev_priv, 2 * page_count, *s++);
+ i915_gem_shrink(dev_priv, 2 * page_count, NULL, *s++);
cond_resched();
/* We've tried hard to allocate the memory by reaping
@@ -5143,7 +5143,7 @@ int i915_gem_freeze_late(struct drm_i915_private *dev_priv)
* the objects as well, see i915_gem_freeze()
*/
- i915_gem_shrink(dev_priv, -1UL, I915_SHRINK_UNBOUND);
+ i915_gem_shrink(dev_priv, -1UL, NULL, I915_SHRINK_UNBOUND);
i915_gem_drain_freed_objects(dev_priv);
spin_lock(&dev_priv->mm.obj_lock);
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index fc3ba03fe85b..aff2a7f43259 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -2131,7 +2131,7 @@ int i915_gem_gtt_prepare_pages(struct drm_i915_gem_object *obj,
*/
GEM_BUG_ON(obj->mm.pages == pages);
} while (i915_gem_shrink(to_i915(obj->base.dev),
- obj->base.size >> PAGE_SHIFT,
+ obj->base.size >> PAGE_SHIFT, NULL,
I915_SHRINK_BOUND |
I915_SHRINK_UNBOUND |
I915_SHRINK_ACTIVE));
diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c b/drivers/gpu/drm/i915/i915_gem_shrinker.c
index 9e8d7433c20f..36f150c99d5d 100644
--- a/drivers/gpu/drm/i915/i915_gem_shrinker.c
+++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c
@@ -204,6 +204,7 @@ static void __start_writeback(struct drm_i915_gem_object *obj,
* i915_gem_shrink - Shrink buffer object caches
* @dev_priv: i915 device
* @target: amount of memory to make available, in pages
+ * @nr_scanned: optional output for number of pages scanned (incremental)
* @flags: control flags for selecting cache types
*
* This function is the main interface to the shrinker. It will try to release
@@ -226,7 +227,9 @@ static void __start_writeback(struct drm_i915_gem_object *obj,
*/
unsigned long
i915_gem_shrink(struct drm_i915_private *dev_priv,
- unsigned long target, unsigned flags)
+ unsigned long target,
+ unsigned long *nr_scanned,
+ unsigned flags)
{
const struct {
struct list_head *list;
@@ -237,6 +240,7 @@ i915_gem_shrink(struct drm_i915_private *dev_priv,
{ NULL, 0 },
}, *phase;
unsigned long count = 0;
+ unsigned long scanned = 0;
bool unlock;
if (!shrinker_lock(dev_priv, &unlock))
@@ -324,6 +328,7 @@ i915_gem_shrink(struct drm_i915_private *dev_priv,
}
mutex_unlock(&obj->mm.lock);
}
+ scanned += obj->base.size >> PAGE_SHIFT;
spin_lock(&dev_priv->mm.obj_lock);
}
@@ -338,6 +343,8 @@ i915_gem_shrink(struct drm_i915_private *dev_priv,
shrinker_unlock(dev_priv, unlock);
+ if (nr_scanned)
+ *nr_scanned += scanned;
return count;
}
@@ -360,7 +367,7 @@ unsigned long i915_gem_shrink_all(struct drm_i915_private *dev_priv)
unsigned long freed;
intel_runtime_pm_get(dev_priv);
- freed = i915_gem_shrink(dev_priv, -1UL,
+ freed = i915_gem_shrink(dev_priv, -1UL, NULL,
I915_SHRINK_BOUND |
I915_SHRINK_UNBOUND |
I915_SHRINK_ACTIVE);
@@ -417,24 +424,29 @@ i915_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
unsigned long freed;
bool unlock;
+ sc->nr_scanned = 0;
+
if (!shrinker_lock(dev_priv, &unlock))
return SHRINK_STOP;
freed = i915_gem_shrink(dev_priv,
sc->nr_to_scan,
+ &sc->nr_scanned,
I915_SHRINK_BOUND |
I915_SHRINK_UNBOUND |
I915_SHRINK_PURGEABLE);
if (freed < sc->nr_to_scan)
freed += i915_gem_shrink(dev_priv,
- sc->nr_to_scan - freed,
+ sc->nr_to_scan - sc->nr_scanned,
+ &sc->nr_scanned,
I915_SHRINK_BOUND |
I915_SHRINK_UNBOUND |
I915_SHRINK_WRITEBACK);
if (freed < sc->nr_to_scan && current_is_kswapd()) {
intel_runtime_pm_get(dev_priv);
freed += i915_gem_shrink(dev_priv,
- sc->nr_to_scan - freed,
+ sc->nr_to_scan - sc->nr_scanned,
+ &sc->nr_scanned,
I915_SHRINK_ACTIVE |
I915_SHRINK_BOUND |
I915_SHRINK_UNBOUND |
@@ -444,7 +456,7 @@ i915_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
shrinker_unlock(dev_priv, unlock);
- return freed;
+ return sc->nr_scanned ? freed : SHRINK_STOP;
}
static bool
@@ -480,7 +492,7 @@ i915_gem_shrinker_oom(struct notifier_block *nb, unsigned long event, void *ptr)
unsigned long unevictable, bound, unbound, freed_pages;
intel_runtime_pm_get(dev_priv);
- freed_pages = i915_gem_shrink(dev_priv, -1UL,
+ freed_pages = i915_gem_shrink(dev_priv, -1UL, NULL,
I915_SHRINK_BOUND |
I915_SHRINK_UNBOUND |
I915_SHRINK_ACTIVE |
@@ -539,7 +551,7 @@ i915_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr
goto out;
intel_runtime_pm_get(dev_priv);
- freed_pages += i915_gem_shrink(dev_priv, -1UL,
+ freed_pages += i915_gem_shrink(dev_priv, -1UL, NULL,
I915_SHRINK_BOUND |
I915_SHRINK_UNBOUND |
I915_SHRINK_ACTIVE |
--
2.14.1
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