From: Greg KH <gregkh@linuxfoundation.org>
To: Tejun Heo <tj@kernel.org>
Cc: kernel-team@fb.com, linux-kernel@vger.kernel.org,
cgroups@vger.kernel.org, lizefan@huawei.com, hannes@cmpxchg.org,
namhyung@kernel.org, ast@kernel.org, daniel@iogearbox.net
Subject: Re: [PATCHSET cgroup/for-5.5] kernfs,cgroup: support 64bit inos and unify cgroup IDs
Date: Tue, 12 Nov 2019 17:09:33 +0100 [thread overview]
Message-ID: <20191112160933.GA1690816@kroah.com> (raw)
In-Reply-To: <20191104235944.3470866-1-tj@kernel.org>
On Mon, Nov 04, 2019 at 03:59:34PM -0800, Tejun Heo wrote:
> Hello,
>
> Currently, there are three IDs which are being used to identify a
> cgroup.
>
> 1. cgroup->id
> 2. cgroupfs 32bit ino
> 3. cgroupfs 32bit ino + 32bit gen
>
> All three IDs are visible to userland through different interfaces.
> This is very confusing and #1 can't even be resolved to cgroups from
> userland.
>
> A 64bit number is sufficient to identify a cgroup instance uniquely
> and ino_t is 64bit on all archs except for alpha. There's no reason
> for three different IDs at all. This patchset updates kernfs so that
> it supports 64bit ino and associated exportfs operations and unifies
> the cgroup IDs.
>
> * On 64bit ino archs, ino is kernfs node ID which is also the cgroup
> ID. The ino can be passed directly into open_by_handle_at(2) w/ the
> new key type FILEID_KERNFS. Backward compatibility is maintained
> for FILEID_INO32_GEN keys.
>
> * On 32bit ino archs, kernfs node ID is still 64bit and the cgroup ID.
> ino is the low 32bits and gen is the high 32bits. If the high
> 32bits is zero, open_by_handle_at(2) only matches the ino part of
> the ID allowing userland to resolve inos to cgroups as long as
> distinguishing recycled inos isn't necessary.
>
> This patchset contains the following 10 patches.
>
> 0001-kernfs-fix-ino-wrap-around-detection.patch
> 0002-writeback-use-ino_t-for-inodes-in-tracepoints.patch
> 0003-netprio-use-css-ID-instead-of-cgroup-ID.patch
> 0004-kernfs-use-dumber-locking-for-kernfs_find_and_get_no.patch
> 0005-kernfs-kernfs_find_and_get_node_by_ino-should-only-l.patch
> 0006-kernfs-convert-kernfs_node-id-from-union-kernfs_node.patch
> 0007-kernfs-combine-ino-id-lookup-functions-into-kernfs_f.patch
> 0008-kernfs-implement-custom-exportfs-ops-and-fid-type.patch
> 0009-kernfs-use-64bit-inos-if-ino_t-is-64bit.patch
> 0010-cgroup-use-cgrp-kn-id-as-the-cgroup-ID.patch
>
> 0001 is a fix which should be backported through -stable. 0002 and
> 0003 are prep patches. 0004-0009 make kernfs_node->id a u64 and use
> it as ino on 64bit ino archs. 0010 replaces cgroup->id with the
> kernfs node ID.
>
> Greg, how do you want to route the patches? We can route 0001-0009
> through your tree and the last one through cgroup after pulling in.
> I'd be happy to route them all too.
Sorry for the delay. Feel free to take all of these through your tree,
that probably is easiest:
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
next prev parent reply other threads:[~2019-11-12 16:09 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-04 23:59 [PATCHSET cgroup/for-5.5] kernfs,cgroup: support 64bit inos and unify cgroup IDs Tejun Heo
2019-11-04 23:59 ` [PATCH 01/10] kernfs: fix ino wrap-around detection Tejun Heo
2019-11-04 23:59 ` [PATCH 02/10] writeback: use ino_t for inodes in tracepoints Tejun Heo
2019-11-05 9:11 ` Jan Kara
2019-11-04 23:59 ` [PATCH 03/10] netprio: use css ID instead of cgroup ID Tejun Heo
2019-11-05 13:27 ` Neil Horman
2019-11-04 23:59 ` [PATCH 04/10] kernfs: use dumber locking for kernfs_find_and_get_node_by_ino() Tejun Heo
2019-11-04 23:59 ` [PATCH 05/10] kernfs: kernfs_find_and_get_node_by_ino() should only look up activated nodes Tejun Heo
2019-11-04 23:59 ` [PATCH 06/10] kernfs: convert kernfs_node->id from union kernfs_node_id to u64 Tejun Heo
2019-11-04 23:59 ` [PATCH 07/10] kernfs: combine ino/id lookup functions into kernfs_find_and_get_node_by_id() Tejun Heo
2019-11-04 23:59 ` [PATCH 08/10] kernfs: implement custom exportfs ops and fid type Tejun Heo
2019-11-04 23:59 ` [PATCH 09/10] kernfs: use 64bit inos if ino_t is 64bit Tejun Heo
2019-11-04 23:59 ` [PATCH 10/10] cgroup: use cgrp->kn->id as the cgroup ID Tejun Heo
2019-11-06 13:50 ` [PATCHSET cgroup/for-5.5] kernfs,cgroup: support 64bit inos and unify cgroup IDs Namhyung Kim
2019-11-07 15:31 ` Tejun Heo
2019-11-12 15:51 ` Tejun Heo
2019-11-12 16:08 ` Greg KH
2019-11-12 16:09 ` Greg KH [this message]
2019-11-12 16:19 ` Tejun Heo
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