Commit 9fab8a2e authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Removing polling for struct_mutex from vmap shrinker 



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.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190109164204.23935-2-chris@chris-wilson.co.uk
parent 3824e419

drivers/gpu/drm/i915/i915_gem_shrinker.c

+4 −31
Original line number Diff line number Diff line
@@ -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,

	if (i915_gem_wait_for_idle(i915,

				   I915_WAIT_LOCKED,

				     MAX_SCHEDULE_TIMEOUT);

	if (ret)

				   MAX_SCHEDULE_TIMEOUT))

		goto out;



	intel_runtime_pm_get(i915);

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