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Diffstat (limited to 'arch/powerpc/platforms/pseries/dtl.c')
-rw-r--r--arch/powerpc/platforms/pseries/dtl.c23
1 files changed, 12 insertions, 11 deletions
diff --git a/arch/powerpc/platforms/pseries/dtl.c b/arch/powerpc/platforms/pseries/dtl.c
index ab5de985a787..2b87480f2837 100644
--- a/arch/powerpc/platforms/pseries/dtl.c
+++ b/arch/powerpc/platforms/pseries/dtl.c
@@ -27,13 +27,7 @@ struct dtl {
};
static DEFINE_PER_CPU(struct dtl, cpu_dtl);
-/*
- * Dispatch trace log event mask:
- * 0x7: 0x1: voluntary virtual processor waits
- * 0x2: time-slice preempts
- * 0x4: virtual partition memory page faults
- */
-static u8 dtl_event_mask = 0x7;
+static u8 dtl_event_mask = DTL_LOG_ALL;
/*
@@ -48,7 +42,6 @@ struct dtl_ring {
struct dtl_entry *write_ptr;
struct dtl_entry *buf;
struct dtl_entry *buf_end;
- u8 saved_dtl_mask;
};
static DEFINE_PER_CPU(struct dtl_ring, dtl_rings);
@@ -98,7 +91,6 @@ static int dtl_start(struct dtl *dtl)
dtlr->write_ptr = dtl->buf;
/* enable event logging */
- dtlr->saved_dtl_mask = lppaca_of(dtl->cpu).dtl_enable_mask;
lppaca_of(dtl->cpu).dtl_enable_mask |= dtl_event_mask;
dtl_consumer = consume_dtle;
@@ -116,7 +108,7 @@ static void dtl_stop(struct dtl *dtl)
dtlr->buf = NULL;
/* restore dtl_enable_mask */
- lppaca_of(dtl->cpu).dtl_enable_mask = dtlr->saved_dtl_mask;
+ lppaca_of(dtl->cpu).dtl_enable_mask = DTL_LOG_PREEMPT;
if (atomic_dec_and_test(&dtl_count))
dtl_consumer = NULL;
@@ -188,11 +180,16 @@ static int dtl_enable(struct dtl *dtl)
if (dtl->buf)
return -EBUSY;
+ /* ensure there are no other conflicting dtl users */
+ if (!read_trylock(&dtl_access_lock))
+ return -EBUSY;
+
n_entries = dtl_buf_entries;
buf = kmem_cache_alloc_node(dtl_cache, GFP_KERNEL, cpu_to_node(dtl->cpu));
if (!buf) {
printk(KERN_WARNING "%s: buffer alloc failed for cpu %d\n",
__func__, dtl->cpu);
+ read_unlock(&dtl_access_lock);
return -ENOMEM;
}
@@ -209,8 +206,11 @@ static int dtl_enable(struct dtl *dtl)
}
spin_unlock(&dtl->lock);
- if (rc)
+ if (rc) {
+ read_unlock(&dtl_access_lock);
kmem_cache_free(dtl_cache, buf);
+ }
+
return rc;
}
@@ -222,6 +222,7 @@ static void dtl_disable(struct dtl *dtl)
dtl->buf = NULL;
dtl->buf_entries = 0;
spin_unlock(&dtl->lock);
+ read_unlock(&dtl_access_lock);
}
/* file interface */