[lustre-devel] [PATCH 09/15] lustre: obdclass: Wake up entire queue of requests on close completion

[James Simmons]

From: Oleg Drokin <green at whamcloud.com>

Since close requests could be stuck behind normal requests and get
more slots we need to wake up entire accumulated queue waiting
for the next modrpc slot or have additional waitqueue just for
close requests.

This patch goes with the former approach.

Fixes: 7cb15d0448 ("staging: lustre: mdc: manage number of modify RPCs in flight")
WC-bug-id: https://jira.whamcloud.com/browse/LU-10948
Lustre-commit: a4e1567d67559b797 ("LU-14741 obdclass: Wake up entire queue of requests on close completion")
Signed-off-by: Oleg Drokin <green at whamcloud.com>
Reviewed-on: https://review.whamcloud.com/43941
Reviewed-by: Andreas Dilger <adilger at whamcloud.com>
Reviewed-by: James Simmons <jsimmons at infradead.org>
Reviewed-by: Neil Brown <neilb at suse.de>
Signed-off-by: James Simmons <jsimmons at infradead.org>
---
 fs/lustre/obdclass/genops.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/lustre/obdclass/genops.c b/fs/lustre/obdclass/genops.c
index bbb63b2..4e89e0a 100644
--- a/fs/lustre/obdclass/genops.c
+++ b/fs/lustre/obdclass/genops.c
@@ -1587,6 +1587,10 @@ void obd_put_mod_rpc_slot(struct client_obd *cli, u32 opc, u16 tag)
 	LASSERT(tag - 1 < OBD_MAX_RIF_MAX);
 	LASSERT(test_and_clear_bit(tag - 1, cli->cl_mod_tag_bitmap) != 0);
 	spin_unlock(&cli->cl_mod_rpcs_lock);
-	wake_up(&cli->cl_mod_rpcs_waitq);
+	/* LU-14741 - to prevent close RPCs stuck behind normal ones */
+	if (close_req)
+		wake_up_all(&cli->cl_mod_rpcs_waitq);
+	else
+		wake_up(&cli->cl_mod_rpcs_waitq);
 }
 EXPORT_SYMBOL(obd_put_mod_rpc_slot);
-- 
1.8.3.1