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authorMaarten Lankhorst <maarten.lankhorst@linux.intel.com>2024-05-28 22:21:34 +0200
committerMaarten Lankhorst <maarten.lankhorst@linux.intel.com>2024-05-28 22:21:34 +0200
commitf73a058be5d70dd81a43f16b2bbff4b1576a7af8 (patch)
treeb7959c01cf7a5d95c7c4d5b61929ff9123370322 /lib/dynamic_queue_limits.c
parentdma-buf: handle testing kthreads creation failure (diff)
parentMerge tag 'drm-misc-fixes-2024-05-23' of https://gitlab.freedesktop.org/drm/misc/kernel into drm-fixes (diff)
downloadwireguard-linux-f73a058be5d70dd81a43f16b2bbff4b1576a7af8.tar.xz
wireguard-linux-f73a058be5d70dd81a43f16b2bbff4b1576a7af8.zip
Merge remote-tracking branch 'drm/drm-fixes' into drm-misc-fixes
v6.10-rc1 is released, forward from v6.9 Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Diffstat (limited to 'lib/dynamic_queue_limits.c')
-rw-r--r--lib/dynamic_queue_limits.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/lib/dynamic_queue_limits.c b/lib/dynamic_queue_limits.c
index a1389db1c30a..e49deddd3de9 100644
--- a/lib/dynamic_queue_limits.c
+++ b/lib/dynamic_queue_limits.c
@@ -15,12 +15,10 @@
#define POSDIFF(A, B) ((int)((A) - (B)) > 0 ? (A) - (B) : 0)
#define AFTER_EQ(A, B) ((int)((A) - (B)) >= 0)
-static void dql_check_stall(struct dql *dql)
+static void dql_check_stall(struct dql *dql, unsigned short stall_thrs)
{
- unsigned short stall_thrs;
unsigned long now;
- stall_thrs = READ_ONCE(dql->stall_thrs);
if (!stall_thrs)
return;
@@ -86,9 +84,16 @@ void dql_completed(struct dql *dql, unsigned int count)
{
unsigned int inprogress, prev_inprogress, limit;
unsigned int ovlimit, completed, num_queued;
+ unsigned short stall_thrs;
bool all_prev_completed;
num_queued = READ_ONCE(dql->num_queued);
+ /* Read stall_thrs in advance since it belongs to the same (first)
+ * cache line as ->num_queued. This way, dql_check_stall() does not
+ * need to touch the first cache line again later, reducing the window
+ * of possible false sharing.
+ */
+ stall_thrs = READ_ONCE(dql->stall_thrs);
/* Can't complete more than what's in queue */
BUG_ON(count > num_queued - dql->num_completed);
@@ -178,7 +183,7 @@ void dql_completed(struct dql *dql, unsigned int count)
dql->num_completed = completed;
dql->prev_num_queued = num_queued;
- dql_check_stall(dql);
+ dql_check_stall(dql, stall_thrs);
}
EXPORT_SYMBOL(dql_completed);