From ef81737b5de01fd8b54c693125e0a3fe9f00e217 Mon Sep 17 00:00:00 2001
From: zam <zam>
Date: Tue, 9 Dec 2008 18:39:22 +0000
Subject: [PATCH] Branch HEAD b=17461 i=r.read i=tappro
avoid nesting of obd_uncommitted_replies and rs_lock locks
in ptlrpc_handle_rs.
---
lustre/ptlrpc/service.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/lustre/ptlrpc/service.c b/lustre/ptlrpc/service.c
index 07e3c80ec8..cb101cf6c1 100644
--- a/lustre/ptlrpc/service.c
+++ b/lustre/ptlrpc/service.c
@@ -1598,19 +1598,19 @@ ptlrpc_handle_rs (struct ptlrpc_reply_state *rs)
list_del_init (&rs->rs_exp_list);
spin_unlock (&exp->exp_lock);
- spin_lock(&rs->rs_lock);
-
- been_handled = rs->rs_handled;
- rs->rs_handled = 1;
-
- if (!list_empty(&rs->rs_obd_list)) {
- spin_unlock(&rs->rs_lock);
+ /* Avoid obd_uncommitted_replies_lock contention if we 100% sure that
+ * rs has been removed from the list already */
+ if (!list_empty_careful(&rs->rs_obd_list)) {
spin_lock(&obd->obd_uncommitted_replies_lock);
- spin_lock(&rs->rs_lock);
list_del_init(&rs->rs_obd_list);
spin_unlock(&obd->obd_uncommitted_replies_lock);
}
+ spin_lock(&rs->rs_lock);
+
+ been_handled = rs->rs_handled;
+ rs->rs_handled = 1;
+
nlocks = rs->rs_nlocks; /* atomic "steal", but */
rs->rs_nlocks = 0; /* locks still on rs_locks! */
--
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