Messages in this thread Patch in this message | | | From | Lai Jiangshan <> | Subject | [PATCH 4/6] remove flip_idx_and_wait() | Date | Tue, 6 Mar 2012 17:57:36 +0800 |
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flip and check are the basic steps of gp. call them directly.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> --- kernel/srcu.c | 35 +++++++++++++++++------------------ 1 files changed, 17 insertions(+), 18 deletions(-)
diff --git a/kernel/srcu.c b/kernel/srcu.c index d5f3450..d101ed5 100644 --- a/kernel/srcu.c +++ b/kernel/srcu.c @@ -300,23 +300,12 @@ static void wait_idx(struct srcu_struct *sp, int idx, int trycount) } /* - * Flip the readers' index by incrementing ->completed, then wait - * until there are no more readers using the counters referenced by - * the old index value. (Recall that the index is the bottom bit - * of ->completed.) - * - * Of course, it is possible that a reader might be delayed for the - * full duration of flip_idx_and_wait() between fetching the - * index and incrementing its counter. This possibility is handled - * by the next __synchronize_srcu() invoking wait_idx() for such readers - * before starting a new grace period. + * Flip the readers' index by incrementing ->completed, then new + * readers will use counters referenced on new index value. */ -static void flip_idx_and_wait(struct srcu_struct *sp, int trycount) +static void srcu_flip(struct srcu_struct *sp) { - int idx; - - idx = sp->completed++ & 0x1; - wait_idx(sp, idx, trycount); + ACCESS_ONCE(sp->completed)++; } /* @@ -362,10 +351,20 @@ static void __synchronize_srcu(struct srcu_struct *sp, int trycount) /* * Now that wait_idx() has waited for the really old readers, - * invoke flip_idx_and_wait() to flip the counter and wait - * for current SRCU readers. + * + * Flip the readers' index by incrementing ->completed, then wait + * until there are no more readers using the counters referenced by + * the old index value. (Recall that the index is the bottom bit + * of ->completed.) + * + * Of course, it is possible that a reader might be delayed for the + * full duration of flip_idx_and_wait() between fetching the + * index and incrementing its counter. This possibility is handled + * by the next __synchronize_srcu() invoking wait_idx() for such + * readers before starting a new grace period. */ - flip_idx_and_wait(sp, trycount); + srcu_flip(sp); + wait_idx(sp, (sp->completed - 1) & 0x1, trycount); mutex_unlock(&sp->mutex); } -- 1.7.4.4
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