linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
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>

  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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20191112160933.GA1690816@kroah.com \
    --to=gregkh@linuxfoundation.org \
    --cc=ast@kernel.org \
    --cc=cgroups@vger.kernel.org \
    --cc=daniel@iogearbox.net \
    --cc=hannes@cmpxchg.org \
    --cc=kernel-team@fb.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=lizefan@huawei.com \
    --cc=namhyung@kernel.org \
    --cc=tj@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).