From: Chao Yu <yuchao0@huawei.com>
To: <jaegeuk@kernel.org>
Cc: <linux-f2fs-devel@lists.sourceforge.net>,
<linux-kernel@vger.kernel.org>, <chao@kernel.org>,
Chao Yu <yuchao0@huawei.com>
Subject: [PATCH 3/3] f2fs: update comments for explicit memory barrier
Date: Sat, 20 Feb 2021 17:38:43 +0800 [thread overview]
Message-ID: <20210220093843.64379-3-yuchao0@huawei.com> (raw)
In-Reply-To: <20210220093843.64379-1-yuchao0@huawei.com>
Add more detailed comments for explicit memory barrier used by
f2fs, in order to enhance code readability.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
---
fs/f2fs/checkpoint.c | 6 +++++-
fs/f2fs/segment.c | 6 +++++-
2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 174a0819ad96..c75866cd72fa 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -1818,7 +1818,11 @@ int f2fs_issue_checkpoint(struct f2fs_sb_info *sbi)
llist_add(&req.llnode, &cprc->issue_list);
atomic_inc(&cprc->queued_ckpt);
- /* update issue_list before we wake up issue_checkpoint thread */
+ /*
+ * update issue_list before we wake up issue_checkpoint thread,
+ * this smp_mb() pairs with another barrier in ___wait_event(),
+ * see more details in comments of waitqueue_active().
+ */
smp_mb();
if (waitqueue_active(&cprc->ckpt_wait_queue))
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 2190910c68b0..2d5a82c4ca15 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -663,7 +663,11 @@ int f2fs_issue_flush(struct f2fs_sb_info *sbi, nid_t ino)
llist_add(&cmd.llnode, &fcc->issue_list);
- /* update issue_list before we wake up issue_flush thread */
+ /*
+ * update issue_list before we wake up issue_flush thread, this
+ * smp_mb() pairs with another barrier in ___wait_event(), see
+ * more details in comments of waitqueue_active().
+ */
smp_mb();
if (waitqueue_active(&fcc->flush_wait_queue))
--
2.29.2
prev parent reply other threads:[~2021-02-20 9:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-20 9:38 [PATCH 1/3] f2fs: avoid unused f2fs_show_compress_options() Chao Yu
2021-02-20 9:38 ` [PATCH 2/3] f2fs: remove unused FORCE_FG_GC macro Chao Yu
2021-02-20 9:38 ` Chao Yu [this message]
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