@@ -251,16 +251,16 @@ EXPORT_SYMBOL_GPL(__srcu_read_unlock);
* we repeatedly block for 1-millisecond time periods. This approach
* has done well in testing, so there is no need for a config parameter.
*/
-#define SYNCHRONIZE_SRCU_READER_DELAY 5
+#define SYNCHRONIZE_SRCU_READER_DELAY 5
+#define SYNCHRONIZE_SRCU_TRYCOUNT 2
+#define SYNCHRONIZE_SRCU_EXP_TRYCOUNT 12
/*
* Wait until all the readers(which starts before this wait_idx()
* with the specified idx) complete.
*/
-static void wait_idx(struct srcu_struct *sp, int idx, bool expedited)
+static void wait_idx(struct srcu_struct *sp, int idx, int trycount)
{
- int trycount = 0;
-
/*
* SRCU read-side critical sections are normally short, so wait
* a small amount of time before possibly blocking.
@@ -268,9 +268,10 @@ static void wait_idx(struct srcu_struct *sp, int idx, bool expedited)
if (!srcu_readers_active_idx_check(sp, idx)) {
udelay(SYNCHRONIZE_SRCU_READER_DELAY);
while (!srcu_readers_active_idx_check(sp, idx)) {
- if (expedited && ++ trycount < 10)
+ if (trycount > 0) {
+ trycount--;
udelay(SYNCHRONIZE_SRCU_READER_DELAY);
- else
+ } else
schedule_timeout_interruptible(1);
}
}
@@ -284,7 +285,7 @@ static void srcu_flip(struct srcu_struct *sp)
/*
* Helper function for synchronize_srcu() and synchronize_srcu_expedited().
*/
-static void __synchronize_srcu(struct srcu_struct *sp, bool expedited)
+static void __synchronize_srcu(struct srcu_struct *sp, int trycount)
{
int busy_idx;
@@ -301,8 +302,8 @@ static void __synchronize_srcu(struct srcu_struct *sp, bool expedited)
* There are some readers start with idx=0, and some others start
* with idx=1. So two wait_idx()s are enough for synchronize:
* __synchronize_srcu() {
- * wait_idx(sp, 0, expedited);
- * wait_idx(sp, 1, expedited);
+ * wait_idx(sp, 0, trycount);
+ * wait_idx(sp, 1, trycount);
* }
* When it returns, all started readers have complete.
*
@@ -331,7 +332,7 @@ static void __synchronize_srcu(struct srcu_struct *sp, bool expedited)
* Because this probability is not high, wait_idx()
* will normally not need to wait.
*/
- wait_idx(sp, 1 - busy_idx, expedited);
+ wait_idx(sp, 1 - busy_idx, trycount);
/* flip the index to ensure the return of the next wait_idx() */
srcu_flip(sp);
@@ -339,7 +340,7 @@ static void __synchronize_srcu(struct srcu_struct *sp, bool expedited)
/*
* Now that wait_idx() has waited for the really old readers.
*/
- wait_idx(sp, busy_idx, expedited);
+ wait_idx(sp, busy_idx, trycount);
mutex_unlock(&sp->mutex);
}
@@ -360,7 +361,7 @@ static void __synchronize_srcu(struct srcu_struct *sp, bool expedited)
*/
void synchronize_srcu(struct srcu_struct *sp)
{
- __synchronize_srcu(sp, 0);
+ __synchronize_srcu(sp, SYNCHRONIZE_SRCU_TRYCOUNT);
}
EXPORT_SYMBOL_GPL(synchronize_srcu);
@@ -381,7 +382,7 @@ EXPORT_SYMBOL_GPL(synchronize_srcu);
*/
void synchronize_srcu_expedited(struct srcu_struct *sp)
{
- __synchronize_srcu(sp, 1);
+ __synchronize_srcu(sp, SYNCHRONIZE_SRCU_EXP_TRYCOUNT);
}
EXPORT_SYMBOL_GPL(synchronize_srcu_expedited);
Use the value of trycount for the strategy for expedited or not in srcu. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> --- kernel/srcu.c | 27 ++++++++++++++------------- 1 files changed, 14 insertions(+), 13 deletions(-)