The core of srcu is changed, but the comments of synchronize_srcu() describe the old algorithm. Update it to match the new algorithm.
Signed-off-by: Lai Jiangshan <la...@cn.fujitsu.com> --- kernel/srcu.c | 10 ++++++---- 1 files changed, 6 insertions(+), 4 deletions(-) diff --git a/kernel/srcu.c b/kernel/srcu.c index ac08970..55524f6 100644 --- a/kernel/srcu.c +++ b/kernel/srcu.c @@ -446,10 +446,12 @@ static void __synchronize_srcu(struct srcu_struct *sp, int trycount) * synchronize_srcu - wait for prior SRCU read-side critical-section completion * @sp: srcu_struct with which to synchronize. * - * Flip the completed counter, and wait for the old count to drain to zero. - * As with classic RCU, the updater must use some separate means of - * synchronizing concurrent updates. Can block; must be called from - * process context. + * Wait for the count to drain to zero of both indexes. To avoid the + * possible starvation of synchronize_srcu(), it waits for the count of + * the index=((->completed & 1) ^ 1) to drain to zero at first, + * and then flip the completed and wait for the count of the other index. + * + * Can block; must be called from process context. * * Note that it is illegal to call synchronize_srcu() from the corresponding * SRCU read-side critical section; doing so will result in deadlock. -- 1.7.4.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
