From: "tj@kernel.org" <tj@kernel.org>
To: "Boy Wu (吳勃誼)" <Boy.Wu@mediatek.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"boris@bur.io" <boris@bur.io>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"linux-mediatek@lists.infradead.org"
<linux-mediatek@lists.infradead.org>,
"cgroups@vger.kernel.org" <cgroups@vger.kernel.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 15:27:43 -1000 [thread overview]
Message-ID: <Zphvj1kXK2xcKj7J@slm.duckdns.org> (raw)
In-Reply-To: <99af713e187a92f0501482e8344be469f1b3e454.camel@mediatek.com>
Hello,
On Thu, Jul 18, 2024 at 01:21:32AM +0000, Boy Wu (吳勃誼) wrote:
...
> I think this will work, but as I mentioned before, this issue is only
> on 32 bit SMP systems. Replacing u64 sync with spinlock will increase
> overhead on 64 bit systems, because u64 sync does nothing on 64 bit
> systems. However, if it is acceptable, we can proceed with this
> solution.
We can encapsulate the spinlock in some helpers and make them conditional on
32bit. However, the u64_sync -> spinlock conversions in the suggested patch
are all on cold paths, so I doubt it'd be all that noticeable especially
given that the hottest path of them all is already grabbing blkg_stat_lock,
but either way is fine by me.
Thanks.
--
tejun
prev parent reply other threads:[~2024-07-18 1:27 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
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 [this message]
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