From: Andriy Skulysh <c17819@cray.com>
Date: Thu, 12 Apr 2018 13:12:05 +0000 (+0300)
Subject: LU-11004 ptlrpc: Serialize procfs access to scp_hist_reqs using mutex
X-Git-Tag: 2.11.53~30
X-Git-Url: https://git.whamcloud.com/?p=fs%2Flustre-release.git;a=commitdiff_plain;h=413a738a37d7a8cacc41f5843bfe2aef286be62b

LU-11004 ptlrpc: Serialize procfs access to scp_hist_reqs using mutex

scp_hist_reqs list can be quite long thus a lot of
userland processes can waste CPU power in spinlock cycles.

Change-Id: Ic0fa7338569f9a19213a1dc31f5479c96a76d23a
Cray-bug-id: LUS-5833
Signed-off-by: Andriy Skulysh <c17819@cray.com>
Reviewed-by: Andrew Perepechko <c17827@cray.com>
Reviewed-by: Alexander Boyko <c17825@cray.com>
Reviewed-on: https://review.whamcloud.com/32307
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Alexandr Boyko <c17825@cray.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
---

diff --git a/lustre/include/lustre_net.h b/lustre/include/lustre_net.h
index 3afe692..e8d290b 100644
--- a/lustre/include/lustre_net.h
+++ b/lustre/include/lustre_net.h
@@ -1773,6 +1773,8 @@ struct ptlrpc_service_part {
 	 * threads starting & stopping are also protected by this lock.
 	 */
 	spinlock_t			scp_lock  __cfs_cacheline_aligned;
+	/** userland serialization */
+	struct mutex			scp_mutex;
 	/** total # req buffer descs allocated */
 	int				scp_nrqbds_total;
 	/** # posted request buffers for receiving */
diff --git a/lustre/ptlrpc/lproc_ptlrpc.c b/lustre/ptlrpc/lproc_ptlrpc.c
index 400ce64..89d256d 100644
--- a/lustre/ptlrpc/lproc_ptlrpc.c
+++ b/lustre/ptlrpc/lproc_ptlrpc.c
@@ -910,10 +910,12 @@ ptlrpc_lprocfs_svc_req_history_start(struct seq_file *s, loff_t *pos)
 		if (i > cpt) /* make up the lowest position for this CPT */
 			*pos = PTLRPC_REQ_CPT2POS(svc, i);
 
+		mutex_lock(&svcpt->scp_mutex);
 		spin_lock(&svcpt->scp_lock);
 		rc = ptlrpc_lprocfs_svc_req_history_seek(svcpt, srhi,
 				PTLRPC_REQ_POS2SEQ(svc, *pos));
 		spin_unlock(&svcpt->scp_lock);
+		mutex_unlock(&svcpt->scp_mutex);
 		if (rc == 0) {
 			*pos = PTLRPC_REQ_SEQ2POS(svc, srhi->srhi_seq);
 			srhi->srhi_idx = i;
@@ -955,9 +957,11 @@ ptlrpc_lprocfs_svc_req_history_next(struct seq_file *s,
 			seq = srhi->srhi_seq + (1 << svc->srv_cpt_bits);
 		}
 
+		mutex_lock(&svcpt->scp_mutex);
 		spin_lock(&svcpt->scp_lock);
 		rc = ptlrpc_lprocfs_svc_req_history_seek(svcpt, srhi, seq);
 		spin_unlock(&svcpt->scp_lock);
+		mutex_unlock(&svcpt->scp_mutex);
 		if (rc == 0) {
 			*pos = PTLRPC_REQ_SEQ2POS(svc, srhi->srhi_seq);
 			srhi->srhi_idx = i;
@@ -1011,6 +1015,7 @@ static int ptlrpc_lprocfs_svc_req_history_show(struct seq_file *s, void *iter)
 
 	svcpt = svc->srv_parts[srhi->srhi_idx];
 
+	mutex_lock(&svcpt->scp_mutex);
 	spin_lock(&svcpt->scp_lock);
 
 	rc = ptlrpc_lprocfs_svc_req_history_seek(svcpt, srhi, srhi->srhi_seq);
@@ -1051,6 +1056,8 @@ static int ptlrpc_lprocfs_svc_req_history_show(struct seq_file *s, void *iter)
 	}
 
 	spin_unlock(&svcpt->scp_lock);
+	mutex_unlock(&svcpt->scp_mutex);
+
 	return rc;
 }
 
diff --git a/lustre/ptlrpc/service.c b/lustre/ptlrpc/service.c
index 9625af5..78fa186 100644
--- a/lustre/ptlrpc/service.c
+++ b/lustre/ptlrpc/service.c
@@ -605,6 +605,7 @@ ptlrpc_service_part_init(struct ptlrpc_service *svc,
 
 	/* rqbd and incoming request queue */
 	spin_lock_init(&svcpt->scp_lock);
+	mutex_init(&svcpt->scp_mutex);
 	INIT_LIST_HEAD(&svcpt->scp_rqbd_idle);
 	INIT_LIST_HEAD(&svcpt->scp_rqbd_posted);
 	INIT_LIST_HEAD(&svcpt->scp_req_incoming);