From: Greg KH <gregkh@linuxfoundation.org>
To: Yi Tao <escape@linux.alibaba.com>
Cc: tj@kernel.org, lizefan.x@bytedance.com, hannes@cmpxchg.org,
mcgrof@kernel.org, keescook@chromium.org, yzaikin@google.com,
linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
linux-fsdevel@vger.kernel.org, shanpeic@linux.alibaba.com
Subject: Re: [RFC PATCH 2/2] support cgroup pool in v1
Date: Wed, 8 Sep 2021 14:35:56 +0200 [thread overview]
Message-ID: <YTiuLES5qd086qRu@kroah.com> (raw)
In-Reply-To: <03e2b37678c9b2aef4f5dee303b3fb87a565d56b.1631102579.git.escape@linux.alibaba.com>
On Wed, Sep 08, 2021 at 08:15:13PM +0800, Yi Tao wrote:
> Add pool_size interface and delay_time interface. When the user writes
> pool_size, a cgroup pool will be created, and then when the user needs
> to create a cgroup, it will take the fast path protected by spinlock to
> obtain it from the resource pool. Performance is improved by the
> following aspects:
> 1.reduce the critical area for creating cgroups
> 2.reduce the scheduling time of sleep
> 3.avoid competition with other cgroup behaviors which protected
> by cgroup_mutex
>
> The essence of obtaining resources from the pool is kernfs rename. With
> the help of the previous pinned kernfs node function, when the pool is
> enabled, these cgroups will be in the pinned state, and the protection
> of the kernfs data structure will be protected by the specified
> spinlock, thus getting rid of the cgroup_mutex and kernfs_rwsem.
>
> In order to avoid random operations by users, the kernfs nodes of the
> cgroups in the pool will be placed under a hidden kernfs tree, and users
> can not directly touch them. When a user creates a cgroup, it will take
> the fast path, select a node from the hidden tree, and move it to the
> correct position.
>
> As users continue to obtain resources from the pool, the number of
> cgroups in the pool will gradually decrease. When the number is less
> than a certain value, it will be supplemented. In order to avoid
> competition with the currently created cgroup, you can delay this by
> setting delay_time process
>
> Suggested-by: Shanpei Chen <shanpeic@linux.alibaba.com>
> Signed-off-by: Yi Tao <escape@linux.alibaba.com>
> ---
> include/linux/cgroup-defs.h | 16 +++++
> include/linux/cgroup.h | 2 +
> kernel/cgroup/cgroup-v1.c | 139 ++++++++++++++++++++++++++++++++++++++++++++
I thought cgroup v1 was "obsolete" and not getting new features added to
it. What is wrong with just using cgroups 2 instead if you have a
problem with the v1 interface?
thanks,
greg k-h
next prev parent reply other threads:[~2021-09-08 12:36 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-08 12:15 [RFC PATCH 0/2] support cgroup pool in v1 Yi Tao
2021-09-08 12:15 ` [RFC PATCH 1/2] add pinned flags for kernfs node Yi Tao
2021-09-08 12:15 ` [RFC PATCH 2/2] support cgroup pool in v1 Yi Tao
2021-09-08 12:35 ` Greg KH [this message]
[not found] ` <084930d2-057a-04a7-76d1-b2a7bd37deb0@linux.alibaba.com>
2021-09-09 13:27 ` Greg KH
2021-09-10 2:20 ` taoyi.ty
2021-09-10 2:15 ` taoyi.ty
2021-09-10 6:01 ` Greg KH
2021-09-08 12:35 ` [RFC PATCH 1/2] add pinned flags for kernfs node Greg KH
2021-09-10 2:14 ` taoyi.ty
2021-09-10 6:00 ` Greg KH
2021-09-08 12:37 ` [RFC PATCH 0/2] support cgroup pool in v1 Greg KH
2021-09-10 2:11 ` taoyi.ty
2021-09-10 6:01 ` Greg KH
2021-09-10 16:49 ` Tejun Heo
2021-09-13 14:20 ` Christian Brauner
2021-09-13 16:24 ` Tejun Heo
2021-09-08 16:35 ` Tejun Heo
2021-09-10 2:12 ` taoyi.ty
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