On Tue, 22 Aug 2017 14:53:25 +0100 Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> wrote: > 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. It's unclear which tree this is against but I think I got it all fixed up. Please check the changes to i915_gem_shrink(). From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Subject: drm/i915: wire up shrinkctl->nr_scanned 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. Link: http://lkml.kernel.org/r/20170822135325.9191-2-chris@xxxxxxxxxxxxxxxxxx Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx> Cc: Minchan Kim <minchan@xxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Cc: Shaohua Li <shli@xxxxxx> Cc: Christoph Lameter <cl@xxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Cc: Pekka Enberg <penberg@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- 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 | 24 +++++++++++++++------ 5 files changed, 24 insertions(+), 11 deletions(-) diff -puN drivers/gpu/drm/i915/i915_debugfs.c~drm-i915-wire-up-shrinkctl-nr_scanned drivers/gpu/drm/i915/i915_debugfs.c --- a/drivers/gpu/drm/i915/i915_debugfs.c~drm-i915-wire-up-shrinkctl-nr_scanned +++ a/drivers/gpu/drm/i915/i915_debugfs.c @@ -4333,10 +4333,10 @@ 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 -puN drivers/gpu/drm/i915/i915_drv.h~drm-i915-wire-up-shrinkctl-nr_scanned drivers/gpu/drm/i915/i915_drv.h --- a/drivers/gpu/drm/i915/i915_drv.h~drm-i915-wire-up-shrinkctl-nr_scanned +++ a/drivers/gpu/drm/i915/i915_drv.h @@ -3628,6 +3628,7 @@ i915_gem_object_create_internal(struct d /* 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 -puN drivers/gpu/drm/i915/i915_gem.c~drm-i915-wire-up-shrinkctl-nr_scanned drivers/gpu/drm/i915/i915_gem.c --- a/drivers/gpu/drm/i915/i915_gem.c~drm-i915-wire-up-shrinkctl-nr_scanned +++ a/drivers/gpu/drm/i915/i915_gem.c @@ -2408,7 +2408,7 @@ rebuild_st: 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 @@ -5012,7 +5012,7 @@ int i915_gem_freeze_late(struct drm_i915 * 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); mutex_lock(&dev_priv->drm.struct_mutex); diff -puN drivers/gpu/drm/i915/i915_gem_gtt.c~drm-i915-wire-up-shrinkctl-nr_scanned drivers/gpu/drm/i915/i915_gem_gtt.c --- a/drivers/gpu/drm/i915/i915_gem_gtt.c~drm-i915-wire-up-shrinkctl-nr_scanned +++ a/drivers/gpu/drm/i915/i915_gem_gtt.c @@ -2061,7 +2061,7 @@ int i915_gem_gtt_prepare_pages(struct dr */ 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 -puN drivers/gpu/drm/i915/i915_gem_shrinker.c~drm-i915-wire-up-shrinkctl-nr_scanned drivers/gpu/drm/i915/i915_gem_shrinker.c --- a/drivers/gpu/drm/i915/i915_gem_shrinker.c~drm-i915-wire-up-shrinkctl-nr_scanned +++ a/drivers/gpu/drm/i915/i915_gem_shrinker.c @@ -136,6 +136,7 @@ static bool unsafe_drop_pages(struct drm * 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 @@ -158,7 +159,9 @@ static bool unsafe_drop_pages(struct drm */ 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; @@ -169,6 +172,7 @@ i915_gem_shrink(struct drm_i915_private { NULL, 0 }, }, *phase; unsigned long count = 0; + unsigned long scanned = 0; bool unlock; if (!shrinker_lock(dev_priv, &unlock)) @@ -249,6 +253,7 @@ i915_gem_shrink(struct drm_i915_private count += obj->base.size >> PAGE_SHIFT; } mutex_unlock(&obj->mm.lock); + scanned += obj->base.size >> PAGE_SHIFT; } } list_splice_tail(&still_in_list, phase->list); @@ -261,6 +266,8 @@ i915_gem_shrink(struct drm_i915_private shrinker_unlock(dev_priv, unlock); + if (nr_scanned) + *nr_scanned += scanned; return count; } @@ -283,7 +290,7 @@ unsigned long i915_gem_shrink_all(struct 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); @@ -329,23 +336,28 @@ i915_gem_shrinker_scan(struct shrinker * 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); 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); @@ -354,7 +366,7 @@ i915_gem_shrinker_scan(struct shrinker * shrinker_unlock(dev_priv, unlock); - return freed; + return sc->nr_scanned ? freed : SHRINK_STOP; } static bool @@ -453,7 +465,7 @@ i915_gem_shrinker_vmap(struct notifier_b 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 | _ _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
