From: Huaisheng Ye <yehs2007@zoho.com>
To: mpatocka@redhat.com, snitzer@redhat.com, agk@redhat.com
Cc: prarit@redhat.com, tyu1@lenovo.com, dm-devel@redhat.com,
linux-kernel@vger.kernel.org, Huaisheng Ye <yehs1@lenovo.com>
Subject: [PATCH 2/3] dm writecache: add unlikely for getting two block with same LBA
Date: Sun, 25 Aug 2019 15:24:32 +0800 [thread overview]
Message-ID: <20190825072433.2628-3-yehs2007@zoho.com> (raw)
In-Reply-To: <20190825072433.2628-1-yehs2007@zoho.com>
From: Huaisheng Ye <yehs1@lenovo.com>
In function writecache_writeback, entries g and f has same original
sector only happens at entry f has been committed, but entry g has
NOT yet.
The probability of this happening is very low in the following
256 blocks at most of entry e.
Signed-off-by: Huaisheng Ye <yehs1@lenovo.com>
Acked-by: Mikulas Patocka <mpatocka@redhat.com>
---
drivers/md/dm-writecache.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index 5c7009d..3643084 100644
--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -1628,8 +1628,8 @@ static void writecache_writeback(struct work_struct *work)
if (unlikely(!next_node))
break;
g = container_of(next_node, struct wc_entry, rb_node);
- if (read_original_sector(wc, g) ==
- read_original_sector(wc, f)) {
+ if (unlikely(read_original_sector(wc, g) ==
+ read_original_sector(wc, f))) {
f = g;
continue;
}
--
1.8.3.1
next prev parent reply other threads:[~2019-08-25 7:25 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-25 7:24 [PATCH 0/3] optimize writecache_writeback for performance Huaisheng Ye
2019-08-25 7:24 ` [PATCH 1/3] dm writecache: remove unused member pointer in writeback_struct Huaisheng Ye
2019-08-25 7:24 ` Huaisheng Ye [this message]
2019-08-25 7:24 ` [PATCH 3/3] dm writecache: optimize performance by sorting the blocks for writeback_all Huaisheng Ye
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