From: Jens Axboe <axboe@kernel.dk>
To: Tejun Heo <tj@kernel.org>
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-team@fb.com, cgroups@vger.kernel.org
Subject: Re: [PATCH for-5.16/block] iocost: Fix divide-by-zero on donation from low hweight cgroup
Date: Tue, 14 Dec 2021 06:58:20 -0700 [thread overview]
Message-ID: <163949030003.173863.14081933851643062205.b4-ty@kernel.dk> (raw)
In-Reply-To: <Ybfh86iSvpWKxhVM@slm.duckdns.org>
On Mon, 13 Dec 2021 14:14:43 -1000, Tejun Heo wrote:
> The donation calculation logic assumes that the donor has non-zero
> after-donation hweight, so the lowest active hweight a donating cgroup can
> have is 2 so that it can donate 1 while keeping the other 1 for itself.
> Earlier, we only donated from cgroups with sizable surpluses so this
> condition was always true. However, with the precise donation algorithm
> implemented, f1de2439ec43 ("blk-iocost: revamp donation amount
> determination") made the donation amount calculation exact enabling even low
> hweight cgroups to donate.
>
> [...]
Applied, thanks!
[1/1] iocost: Fix divide-by-zero on donation from low hweight cgroup
commit: edaa26334c117a584add6053f48d63a988d25a6e
Best regards,
--
Jens Axboe
WARNING: multiple messages have this Message-ID (diff)
From: Jens Axboe <axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>
To: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: linux-block-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
kernel-team-b10kYP2dOMg@public.gmane.org,
cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH for-5.16/block] iocost: Fix divide-by-zero on donation from low hweight cgroup
Date: Tue, 14 Dec 2021 06:58:20 -0700 [thread overview]
Message-ID: <163949030003.173863.14081933851643062205.b4-ty@kernel.dk> (raw)
In-Reply-To: <Ybfh86iSvpWKxhVM-NiLfg/pYEd1N0TnZuCh8vA@public.gmane.org>
On Mon, 13 Dec 2021 14:14:43 -1000, Tejun Heo wrote:
> The donation calculation logic assumes that the donor has non-zero
> after-donation hweight, so the lowest active hweight a donating cgroup can
> have is 2 so that it can donate 1 while keeping the other 1 for itself.
> Earlier, we only donated from cgroups with sizable surpluses so this
> condition was always true. However, with the precise donation algorithm
> implemented, f1de2439ec43 ("blk-iocost: revamp donation amount
> determination") made the donation amount calculation exact enabling even low
> hweight cgroups to donate.
>
> [...]
Applied, thanks!
[1/1] iocost: Fix divide-by-zero on donation from low hweight cgroup
commit: edaa26334c117a584add6053f48d63a988d25a6e
Best regards,
--
Jens Axboe
next prev parent reply other threads:[~2021-12-14 13:58 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-14 0:14 [PATCH for-5.16/block] iocost: Fix divide-by-zero on donation from low hweight cgroup Tejun Heo
2021-12-14 13:58 ` Jens Axboe [this message]
2021-12-14 13:58 ` Jens Axboe
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