From: "tj@kernel.org" <tj@kernel.org>
To: Waiman Long <longman@redhat.com>
Cc: "Boy Wu (吳勃誼)" <Boy.Wu@mediatek.com>,
"boris@bur.io" <boris@bur.io>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"cgroups@vger.kernel.org" <cgroups@vger.kernel.org>,
"linux-mediatek@lists.infradead.org"
<linux-mediatek@lists.infradead.org>,
"axboe@kernel.dk" <axboe@kernel.dk>,
"Iverlin Wang (王苳霖)" <Iverlin.Wang@mediatek.com>,
"josef@toxicpanda.com" <josef@toxicpanda.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"matthias.bgg@gmail.com" <matthias.bgg@gmail.com>,
"angelogioacchino.delregno@collabora.com"
<angelogioacchino.delregno@collabora.com>
Subject: Re: [PATCH v3] blk-cgroup: Replace u64 sync with spinlock for iostat update
Date: Wed, 17 Jul 2024 07:40:06 -1000 [thread overview]
Message-ID: <ZpgB9kCAxAAXAtSi@slm.duckdns.org> (raw)
In-Reply-To: <f448f66b-7a91-4281-8f77-159541cbacff@redhat.com>
Hello, Waiman.
On Wed, Jul 17, 2024 at 01:37:56PM -0400, Waiman Long wrote:
> bis->sync is still being used in blk_cgroup_bio_start(). Replacing it with a
> global lock may kill performance. We may have to use a per-cpu lock if we
> want to go this route of eliminating bis->sync.
So, the idea is to keep using u64_sync for blkg->iostat_cpu and use
blkg_stat_lock for blkg->iostat. The former is the only one which is updated
in hot path, right?
Thanks.
--
tejun
next prev parent reply other threads:[~2024-07-17 17:40 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-16 7:52 [PATCH v3] blk-cgroup: Replace u64 sync with spinlock for iostat update boy.wu
2024-07-16 21:13 ` Tejun Heo
2024-07-17 2:25 ` Boy Wu (吳勃誼)
2024-07-17 3:44 ` Boy Wu (吳勃誼)
2024-07-17 4:09 ` Boy Wu (吳勃誼)
2024-07-17 16:55 ` tj
2024-07-17 17:37 ` Waiman Long
2024-07-17 17:40 ` tj [this message]
2024-07-17 18:18 ` Waiman Long
2024-07-17 18:24 ` tj
2024-07-17 18:55 ` Waiman Long
2024-07-17 18:57 ` tj
2024-07-18 1:21 ` Boy Wu (吳勃誼)
2024-07-18 1:27 ` tj
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