From: Oleg Nesterov <oleg@redhat.com>
To: Li Nan <linan666@huaweicloud.com>
Cc: Khazhy Kumykov <khazhy@chromium.org>,
tj@kernel.org, josef@toxicpanda.com, axboe@kernel.dk,
yukuai3@huawei.com, cgroups@vger.kernel.org,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
yi.zhang@huawei.com, houtao1@huawei.com, yangerkun@huawei.com
Subject: Re: [PATCH] blk-throttle: Calculate allowed value only when the throttle is enabled
Date: Thu, 5 Oct 2023 19:04:14 +0200 [thread overview]
Message-ID: <20231005170413.GB32420@redhat.com> (raw)
In-Reply-To: <4ace01e8-6815-29d0-70ce-4632818ca701@huaweicloud.com>
sorry, didn't notice this part before.
I am not a asm expert (to say at least;) but
On 10/05, Li Nan wrote:
>
> When (a * mul) overflows, a divide 0 error occurs in
> mul_u64_u64_div_u64().
Just in case... No, iirc it is divq which triggers #DE when the
result of division doesn't fit u64.
(a * mul) can't overflow, the result is 128-bit rax:rdx number.
Oleg.
next prev parent reply other threads:[~2023-10-05 17:15 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-28 1:58 [PATCH] blk-throttle: Calculate allowed value only when the throttle is enabled linan666
2023-10-04 19:31 ` Tejun Heo
2023-10-04 20:30 ` Khazhy Kumykov
2023-10-04 20:44 ` Khazhy Kumykov
[not found] ` <4ace01e8-6815-29d0-70ce-4632818ca701@huaweicloud.com>
2023-10-05 16:24 ` Oleg Nesterov
2023-10-07 1:23 ` Yu Kuai
2023-10-07 15:16 ` Oleg Nesterov
2023-10-08 1:26 ` Yu Kuai
2023-10-08 11:36 ` Oleg Nesterov
2023-10-13 21:51 ` Khazhy Kumykov
2023-10-16 1:46 ` Yu Kuai
2023-10-16 20:06 ` Khazhy Kumykov
2023-10-16 21:48 ` Khazhy Kumykov
2023-10-17 2:38 ` Yu Kuai
2023-10-05 17:04 ` Oleg Nesterov [this message]
2023-10-05 17:15 ` Khazhy Kumykov
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