LU-11852 osc: skip cache entry wakeup without grants

No need to wakeup osc_entry_cache waiters with EDQUOT or insufficent
grants, cause they will sleep again.
osc_enter_cache could skip queue of waiters if client has enough
grants. The fix adds list_empty checking and improves FIFO.

Signed-off-by: Alexander Boyko <c17825@cray.com>
Cray-bug-id: LUS-6119
Change-Id: I0a2415a19b2c8ecd7df3411d88cab9fee2470a10
Reviewed-on: https://review.whamcloud.com/34013
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andriy Skulysh <c17819@cray.com>
Reviewed-by: Andrew Perepechko <c17827@cray.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>

diff --git a/lustre/osc/osc_cache.c b/lustre/osc/osc_cache.c
index 4660212..7721c13 100644 (file)
--- a/lustre/osc/osc_cache.c
+++ b/lustre/osc/osc_cache.c
@@ -1601,7 +1601,8 @@ static int osc_enter_cache(const struct lu_env *env, struct client_obd *cli,
        }
 
        /* Hopefully normal case - cache space and write credits available */
-       if (osc_enter_cache_try(cli, oap, bytes, 0)) {
+       if (list_empty(&cli->cl_cache_waiters) &&
+           osc_enter_cache_try(cli, oap, bytes, 0)) {
                OSC_DUMP_GRANT(D_CACHE, cli, "granted from cache\n");
                GOTO(out, rc = 0);
        }
@@ -1686,27 +1687,21 @@ void osc_wake_cache_waiters(struct client_obd *cli)
        ENTRY;
        list_for_each_safe(l, tmp, &cli->cl_cache_waiters) {
                ocw = list_entry(l, struct osc_cache_waiter, ocw_entry);
-               list_del_init(&ocw->ocw_entry);
 
                ocw->ocw_rc = -EDQUOT;
-               /* we can't dirty more */
-               if ((cli->cl_dirty_pages  >= cli->cl_dirty_max_pages) ||
-                   (1 + atomic_long_read(&obd_dirty_pages) >
-                    obd_max_dirty_pages)) {
-                       CDEBUG(D_CACHE, "no dirty room: dirty: %ld "
-                              "osc max %ld, sys max %ld\n",
-                              cli->cl_dirty_pages, cli->cl_dirty_max_pages,
-                              obd_max_dirty_pages);
-                       goto wakeup;
-               }
 
                if (osc_enter_cache_try(cli, ocw->ocw_oap, ocw->ocw_grant, 0))
                        ocw->ocw_rc = 0;
-wakeup:
-               CDEBUG(D_CACHE, "wake up %p for oap %p, avail grant %ld, %d\n",
-                      ocw, ocw->ocw_oap, cli->cl_avail_grant, ocw->ocw_rc);
 
-               wake_up(&ocw->ocw_waitq);
+               if (ocw->ocw_rc == 0 ||
+                   !(cli->cl_dirty_pages > 0 || cli->cl_w_in_flight > 0)) {
+                       list_del_init(&ocw->ocw_entry);
+                       CDEBUG(D_CACHE, "wake up %p for oap %p, avail grant "
+                              "%ld, %d\n", ocw, ocw->ocw_oap,
+                              cli->cl_avail_grant, ocw->ocw_rc);
+
+                       wake_up(&ocw->ocw_waitq);
+               }
        }
 
        EXIT;