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From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Alban Crequy <alban.crequy@gmail.com>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	containers@lists.linux-foundation.org, cgroups@vger.kernel.org,
	Alban Crequy <alban@kinvolk.io>,
	tj@kernel.org
Subject: Re: [PATCH] [RFC] bpf: tracing: new helper bpf_get_current_cgroup_ino
Date: Mon, 21 May 2018 09:26:11 -0700	[thread overview]
Message-ID: <20180521162609.lpdrnozowmzdn57m@ast-mbp.dhcp.thefacebook.com> (raw)
In-Reply-To: <20180513173318.21680-1-alban@kinvolk.io>

On Sun, May 13, 2018 at 07:33:18PM +0200, Alban Crequy wrote:
>  
> +BPF_CALL_2(bpf_get_current_cgroup_ino, u32, hierarchy, u64, flags)
> +{
> +	// TODO: pick the correct hierarchy instead of the mem controller
> +	struct cgroup *cgrp = task_cgroup(current, memory_cgrp_id);
> +
> +	if (unlikely(!cgrp))
> +		return -EINVAL;
> +	if (unlikely(hierarchy))
> +		return -EINVAL;
> +	if (unlikely(flags))
> +		return -EINVAL;
> +
> +	return cgrp->kn->id.ino;

ino only is not enough to identify cgroup. It needs generation number too.
I don't quite see how hierarchy and flags can be used in the future.
Also why limit it to memcg?

How about something like this instead:

BPF_CALL_2(bpf_get_current_cgroup_id)
{
        struct cgroup *cgrp = task_dfl_cgroup(current);

        return cgrp->kn->id.id;
}
The user space can use fhandle api to get the same 64-bit id.

  parent reply	other threads:[~2018-05-21 16:26 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-13 17:33 [PATCH] [RFC] bpf: tracing: new helper bpf_get_current_cgroup_ino Alban Crequy
2018-05-14 19:38 ` Y Song
2018-05-21 13:52   ` Alban Crequy
2018-05-21 16:26 ` Alexei Starovoitov [this message]
2018-05-22  0:24   ` Y Song
2018-05-23  3:33     ` Y Song
2018-05-23  3:35       ` Alexei Starovoitov
2018-05-23  4:31         ` Y Song
2018-05-23  8:57           ` Daniel Borkmann
2018-05-25 15:21       ` Alban Crequy
2018-05-25 16:28         ` Y Song

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