Under a high NFSv3 load with lots of different file being accessed The
list_lru of garbage-collectable files can become quite long.
Asking lisT_lru_scan() to scan the whole list can result in a long
period during which a spinlock is held and no scheduling is possible.
This is impolite.
So only ask list_lru_scan() to scan 1024 entries at a time, and repeat
if necessary - calling cond_resched() each time.
Signed-off-by: NeilBrown <neilb@xxxxxxx>
---
fs/nfsd/filecache.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
index a1cdba42c4fa..e99a86798e86 100644
--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -543,11 +543,18 @@ nfsd_file_gc(void)
{
LIST_HEAD(dispose);
unsigned long ret;
-
- ret = list_lru_walk(&nfsd_file_lru, nfsd_file_lru_cb,
- &dispose, list_lru_count(&nfsd_file_lru));
- trace_nfsd_file_gc_removed(ret, list_lru_count(&nfsd_file_lru));
- nfsd_file_dispose_list_delayed(&dispose);
+ unsigned long cnt = list_lru_count(&nfsd_file_lru);
+
+ while (cnt > 0) {
+ unsigned long num_to_scan = min(cnt, 1024UL);
+ ret = list_lru_walk(&nfsd_file_lru, nfsd_file_lru_cb,
+ &dispose, num_to_scan);
+ trace_nfsd_file_gc_removed(ret, list_lru_count(&nfsd_file_lru));
+ nfsd_file_dispose_list_delayed(&dispose);
+ cnt -= num_to_scan;
+ if (cnt)
+ cond_resched();
+ }
}
static void
--
2.47.1
