[Xen-devel] [PATCH 3/8] xen/sched: don't use irqsave locks in dumping functions

From: Juergen Gross <jgross@suse.com>
To: xen-devel@lists.xenproject.org
Cc: Juergen Gross <jgross@suse.com>,
	George Dunlap <george.dunlap@eu.citrix.com>,
	Meng Xu <mengxu@cis.upenn.edu>,
	Dario Faggioli <dfaggioli@suse.com>
Subject: [Xen-devel] [PATCH 3/8] xen/sched: don't use irqsave locks in dumping functions
Date: Thu, 13 Feb 2020 13:54:44 +0100	[thread overview]
Message-ID: <20200213125449.14226-4-jgross@suse.com> (raw)
In-Reply-To: <20200213125449.14226-1-jgross@suse.com>

All dumping functions invoked by the "runq" keyhandler are called with
disabled interrupts, so there is no need to use the irqsave variants
of any locks in those functions.

Signed-off-by: Juergen Gross <jgross@suse.com>
---
 xen/common/sched/credit.c  | 10 ++++------
 xen/common/sched/credit2.c |  5 ++---
 xen/common/sched/null.c    | 10 ++++------
 xen/common/sched/rt.c      | 10 ++++------
 4 files changed, 14 insertions(+), 21 deletions(-)

diff --git a/xen/common/sched/credit.c b/xen/common/sched/credit.c
index 05946eea6e..dee87e7fe2 100644
--- a/xen/common/sched/credit.c
+++ b/xen/common/sched/credit.c
@@ -2048,7 +2048,6 @@ csched_dump_pcpu(const struct scheduler *ops, int cpu)
     const struct csched_pcpu *spc;
     const struct csched_unit *svc;
     spinlock_t *lock;
-    unsigned long flags;
     int loop;
 
     /*
@@ -2058,7 +2057,7 @@ csched_dump_pcpu(const struct scheduler *ops, int cpu)
      * - we scan through the runqueue, so we need the proper runqueue
      *   lock (the one of the runqueue of this cpu).
      */
-    spin_lock_irqsave(&prv->lock, flags);
+    spin_lock(&prv->lock);
     lock = pcpu_schedule_lock(cpu);
 
     spc = CSCHED_PCPU(cpu);
@@ -2089,7 +2088,7 @@ csched_dump_pcpu(const struct scheduler *ops, int cpu)
     }
 
     pcpu_schedule_unlock(lock, cpu);
-    spin_unlock_irqrestore(&prv->lock, flags);
+    spin_unlock(&prv->lock);
 }
 
 static void
@@ -2098,9 +2097,8 @@ csched_dump(const struct scheduler *ops)
     struct list_head *iter_sdom, *iter_svc;
     struct csched_private *prv = CSCHED_PRIV(ops);
     int loop;
-    unsigned long flags;
 
-    spin_lock_irqsave(&prv->lock, flags);
+    spin_lock(&prv->lock);
 
     printk("info:\n"
            "\tncpus              = %u\n"
@@ -2153,7 +2151,7 @@ csched_dump(const struct scheduler *ops)
         }
     }
 
-    spin_unlock_irqrestore(&prv->lock, flags);
+    spin_unlock(&prv->lock);
 }
 
 static int __init
diff --git a/xen/common/sched/credit2.c b/xen/common/sched/credit2.c
index f2752f27e2..e76d2ed543 100644
--- a/xen/common/sched/credit2.c
+++ b/xen/common/sched/credit2.c
@@ -3649,14 +3649,13 @@ csched2_dump(const struct scheduler *ops)
 {
     struct list_head *iter_sdom;
     struct csched2_private *prv = csched2_priv(ops);
-    unsigned long flags;
     unsigned int i, j, loop;
 
     /*
      * We need the private scheduler lock as we access global
      * scheduler data and (below) the list of active domains.
      */
-    read_lock_irqsave(&prv->lock, flags);
+    read_lock(&prv->lock);
 
     printk("Active queues: %d\n"
            "\tdefault-weight     = %d\n",
@@ -3749,7 +3748,7 @@ csched2_dump(const struct scheduler *ops)
         spin_unlock(&rqd->lock);
     }
 
-    read_unlock_irqrestore(&prv->lock, flags);
+    read_unlock(&prv->lock);
 }
 
 static void *
diff --git a/xen/common/sched/null.c b/xen/common/sched/null.c
index 8c3101649d..3b31703d7e 100644
--- a/xen/common/sched/null.c
+++ b/xen/common/sched/null.c
@@ -954,9 +954,8 @@ static void null_dump_pcpu(const struct scheduler *ops, int cpu)
     const struct null_pcpu *npc = get_sched_res(cpu)->sched_priv;
     const struct null_unit *nvc;
     spinlock_t *lock;
-    unsigned long flags;
 
-    lock = pcpu_schedule_lock_irqsave(cpu, &flags);
+    lock = pcpu_schedule_lock(cpu);
 
     printk("CPU[%02d] sibling={%*pbl}, core={%*pbl}",
            cpu, CPUMASK_PR(per_cpu(cpu_sibling_mask, cpu)),
@@ -974,17 +973,16 @@ static void null_dump_pcpu(const struct scheduler *ops, int cpu)
         printk("\n");
     }
 
-    pcpu_schedule_unlock_irqrestore(lock, flags, cpu);
+    pcpu_schedule_unlock(lock, cpu);
 }
 
 static void null_dump(const struct scheduler *ops)
 {
     struct null_private *prv = null_priv(ops);
     struct list_head *iter;
-    unsigned long flags;
     unsigned int loop;
 
-    spin_lock_irqsave(&prv->lock, flags);
+    spin_lock(&prv->lock);
 
     printk("\tcpus_free = %*pbl\n", CPUMASK_PR(&prv->cpus_free));
 
@@ -1029,7 +1027,7 @@ static void null_dump(const struct scheduler *ops)
     printk("\n");
     spin_unlock(&prv->waitq_lock);
 
-    spin_unlock_irqrestore(&prv->lock, flags);
+    spin_unlock(&prv->lock);
 }
 
 static const struct scheduler sched_null_def = {
diff --git a/xen/common/sched/rt.c b/xen/common/sched/rt.c
index 66585ed50a..16379cb2d2 100644
--- a/xen/common/sched/rt.c
+++ b/xen/common/sched/rt.c
@@ -353,9 +353,8 @@ rt_dump_pcpu(const struct scheduler *ops, int cpu)
 {
     struct rt_private *prv = rt_priv(ops);
     const struct rt_unit *svc;
-    unsigned long flags;
 
-    spin_lock_irqsave(&prv->lock, flags);
+    spin_lock(&prv->lock);
     printk("CPU[%02d]\n", cpu);
     /* current UNIT (nothing to say if that's the idle unit). */
     svc = rt_unit(curr_on_cpu(cpu));
@@ -363,7 +362,7 @@ rt_dump_pcpu(const struct scheduler *ops, int cpu)
     {
         rt_dump_unit(ops, svc);
     }
-    spin_unlock_irqrestore(&prv->lock, flags);
+    spin_unlock(&prv->lock);
 }
 
 static void
@@ -373,9 +372,8 @@ rt_dump(const struct scheduler *ops)
     struct rt_private *prv = rt_priv(ops);
     const struct rt_unit *svc;
     const struct rt_dom *sdom;
-    unsigned long flags;
 
-    spin_lock_irqsave(&prv->lock, flags);
+    spin_lock(&prv->lock);
 
     if ( list_empty(&prv->sdom) )
         goto out;
@@ -421,7 +419,7 @@ rt_dump(const struct scheduler *ops)
     }
 
  out:
-    spin_unlock_irqrestore(&prv->lock, flags);
+    spin_unlock(&prv->lock);
 }
 
 /*
-- 
2.16.4


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel
