On 09/01/2019 16:42, Chris Wilson wrote:
The wait-for-idle used from within the shrinker_lock_uninterruptible
depends on the struct_mutex locking state being known and declared to
i915_request_wait(). As it is conceivable that we reach the vmap
notifier from underneath struct_mutex (and so keep on relying on the
mutex_trylock_recursive), we should not blindly call i915_request_wait.
In the process we can remove the dubious polling to acquire
struct_mutex, and simply act, or not, on a successful trylock.
Makes sense and removes the special casing. I only miss the historical
reference as to why did vmap notifier need this special handling?
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem_shrinker.c | 35 +++---------------------
1 file changed, 4 insertions(+), 31 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c b/drivers/gpu/drm/i915/i915_gem_shrinker.c
index 8ad9519779cc..6cc2b964c955 100644
--- a/drivers/gpu/drm/i915/i915_gem_shrinker.c
+++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c
@@ -385,31 +385,6 @@ i915_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
return sc->nr_scanned ? freed : SHRINK_STOP;
}
-static bool
-shrinker_lock_uninterruptible(struct drm_i915_private *i915, bool *unlock,
- int timeout_ms)
-{
- unsigned long timeout = jiffies + msecs_to_jiffies_timeout(timeout_ms);
-
- do {
- if (i915_gem_wait_for_idle(i915,
- 0, MAX_SCHEDULE_TIMEOUT) == 0 &&
- shrinker_lock(i915, 0, unlock))
- break;
-
- schedule_timeout_killable(1);
- if (fatal_signal_pending(current))
- return false;
-
- if (time_after(jiffies, timeout)) {
- pr_err("Unable to lock GPU to purge memory.\n");
- return false;
- }
- } while (1);
-
- return true;
-}
-
static int
i915_gem_shrinker_oom(struct notifier_block *nb, unsigned long event, void *ptr)
{
@@ -461,16 +436,14 @@ i915_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr
struct i915_vma *vma, *next;
unsigned long freed_pages = 0;
bool unlock;
- int ret;
- if (!shrinker_lock_uninterruptible(i915, &unlock, 5000))
+ if (!shrinker_lock(i915, 0, &unlock))
return NOTIFY_DONE;
/* Force everything onto the inactive lists */
- ret = i915_gem_wait_for_idle(i915,
- I915_WAIT_LOCKED,
- MAX_SCHEDULE_TIMEOUT);
- if (ret)
+ if (i915_gem_wait_for_idle(i915,
+ I915_WAIT_LOCKED,
+ MAX_SCHEDULE_TIMEOUT))
goto out;
intel_runtime_pm_get(i915);
Regards,
Tvrtko
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