From 3b98a12e339a9e1676e2a6da470c86e1d368853e Mon Sep 17 00:00:00 2001
From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Date: Thu, 16 Dec 2021 15:27:34 +0100
Subject: drm/i915: Change shrink ordering to use locking around unbinding.
Git-commit: e4e80625300390d8846b72d7076fd1a75af6ea60
Patch-mainline: v5.17-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
Call drop_pages with the gem object lock held, instead of the other
way around. This will allow us to drop the vma bindings with the
gem object lock held.
We plan to require the object lock for unpinning in the future,
and this is an easy target.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211216142749.1966107-3-maarten.lankhorst@linux.intel.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/i915/gem/i915_gem_shrinker.c | 38 ++++++++++----------
1 file changed, 18 insertions(+), 20 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
index 05a1ba2f2e7b..6003db8424dc 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
@@ -36,8 +36,8 @@ static bool can_release_pages(struct drm_i915_gem_object *obj)
return swap_available() || obj->mm.madv == I915_MADV_DONTNEED;
}
-static bool unsafe_drop_pages(struct drm_i915_gem_object *obj,
- unsigned long shrink, bool trylock_vm)
+static int drop_pages(struct drm_i915_gem_object *obj,
+ unsigned long shrink, bool trylock_vm)
{
unsigned long flags;
@@ -214,26 +214,24 @@ i915_gem_shrink(struct i915_gem_ww_ctx *ww,
spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
- err = 0;
- if (unsafe_drop_pages(obj, shrink, trylock_vm)) {
- /* May arrive from get_pages on another bo */
- if (!ww) {
- if (!i915_gem_object_trylock(obj))
- goto skip;
- } else {
- err = i915_gem_object_lock(obj, ww);
- if (err)
- goto skip;
- }
-
- if (!__i915_gem_object_put_pages(obj)) {
- if (!try_to_writeback(obj, shrink))
- count += obj->base.size >> PAGE_SHIFT;
- }
- if (!ww)
- i915_gem_object_unlock(obj);
+ /* May arrive from get_pages on another bo */
+ if (!ww) {
+ if (!i915_gem_object_trylock(obj))
+ goto skip;
+ } else {
+ err = i915_gem_object_lock(obj, ww);
+ if (err)
+ goto skip;
}
+ if (drop_pages(obj, shrink, trylock_vm) &&
+ !__i915_gem_object_put_pages(obj) &&
+ !try_to_writeback(obj, shrink))
+ count += obj->base.size >> PAGE_SHIFT;
+
+ if (!ww)
+ i915_gem_object_unlock(obj);
+
scanned += obj->base.size >> PAGE_SHIFT;
skip:
i915_gem_object_put(obj);
--
2.38.1