From: Vipin Sharma <vipinsh@google.com>
To: Tejun Heo <tj@kernel.org>
Cc: mkoutny@suse.com, rdunlap@infradead.org, thomas.lendacky@amd.com,
brijesh.singh@amd.com, jon.grimm@amd.com,
eric.vantassell@amd.com, pbonzini@redhat.com, hannes@cmpxchg.org,
frankja@linux.ibm.com, borntraeger@de.ibm.com, corbet@lwn.net,
seanjc@google.com, vkuznets@redhat.com, wanpengli@tencent.com,
jmattson@google.com, joro@8bytes.org, tglx@linutronix.de,
mingo@redhat.com, bp@alien8.de, hpa@zytor.com,
gingell@google.com, rientjes@google.com, dionnaglaze@google.com,
kvm@vger.kernel.org, x86@kernel.org, cgroups@vger.kernel.org,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC v2 1/2] cgroup: sev: Add misc cgroup controller
Date: Wed, 3 Mar 2021 22:12:32 -0800 [thread overview]
Message-ID: <YEB6ULUgbf+s8ydd@google.com> (raw)
In-Reply-To: <YD+ubbB4Tz0ZlVvp@slm.duckdns.org>
On Wed, Mar 03, 2021 at 10:42:37AM -0500, Tejun Heo wrote:
> > + atomic_t usage;
> > +};
>
> Can we do 64bits so that something which counts memory can use this too?
>
Sure.
> > +
> > + if (usage > capacity)
> > + return -EBUSY;
>
> I'd rather go with allowing bringing down capacity below usage so that the
> users can set it to a lower value to drain existing usages while denying new
> ones. It's not like it's difficult to check the current total usage from the
> caller side, so I'm not sure it's very useful to shift the condition check
> here.
>
Okay, I will change the code to set new capacity unconditionally.
Right now there is no API for the caller to know total usage, unless they
keep their own tally, I was thinking it will be useful to add one more API
unsigned long misc_cg_res_total_usage(enum misc_res_type type)
It will return root_cg usage for "type" resource.
Will it be fine?
> > + pr_info("cgroup: charge rejected by misc controller for %s resource in ",
> > + misc_res_name[type]);
> > + pr_cont_cgroup_path(i->css.cgroup);
> > + pr_cont("\n");
>
> Should have commented on this in the priv thread but don't print something
> on every rejection. This often becomes a nuisance and can make an easy DoS
> vector at worst. If you wanna do it, print it once per cgroup or sth like
> that.
I didn't think in that way. Thanks, I will print it once per cgroup.
Thanks
Vipin
next prev parent reply other threads:[~2021-03-04 6:14 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-02 8:17 [RFC v2 0/2] cgroup: New misc cgroup controller Vipin Sharma
2021-03-02 8:17 ` [RFC v2 1/2] cgroup: sev: Add " Vipin Sharma
2021-03-03 15:42 ` Tejun Heo
2021-03-04 6:12 ` Vipin Sharma [this message]
2021-03-04 8:53 ` Tejun Heo
2021-03-02 8:17 ` [RFC v2 2/2] cgroup: sev: Miscellaneous cgroup documentation Vipin Sharma
2021-03-04 2:55 ` Jacob Pan
2021-03-04 6:22 ` Vipin Sharma
2021-03-04 8:51 ` Tejun Heo
2021-03-12 20:58 ` Jacob Pan
2021-03-12 21:15 ` Vipin Sharma
2021-03-12 22:59 ` Jacob Pan
2021-03-13 10:20 ` Tejun Heo
2021-03-13 16:57 ` Jacob Pan
2021-03-13 18:05 ` Tejun Heo
2021-03-15 22:11 ` Jacob Pan
2021-03-15 22:19 ` Tejun Heo
2021-03-15 23:40 ` Jacob Pan
2021-03-15 23:54 ` Tejun Heo
2021-03-16 1:30 ` Jacob Pan
2021-03-16 2:22 ` Tejun Heo
2021-03-16 18:19 ` Jacob Pan
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