If the system is forced to start kswapd to recover pages, the system is
very starved. Fortunately, kswapd is its own process context and can
wait for the mutex.
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
drivers/gpu/drm/i915/i915_gem.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index ff2ea2b..7108493 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4600,8 +4600,16 @@ i915_gem_inactive_shrink(struct shrinker *shrinker, struct shrink_control *sc)
int nr_to_scan = sc->nr_to_scan;
int cnt;
- if (!mutex_trylock(&dev->struct_mutex))
- return 0;
+ /* Force reaping when kswapd runs and the system is starved of
+ * free pages, Otherwise only opportunistically shrink our caches,
+ * being wary of deadlocks.
+ */
+ if (current_is_kswapd()) {
+ mutex_lock(&dev->struct_mutex);
+ } else {
+ if (!mutex_trylock(&dev->struct_mutex))
+ return 0;
+ }
if (nr_to_scan) {
nr_to_scan -= i915_gem_purge(dev_priv, nr_to_scan);
--
1.7.10.4
