From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Subject: Re: [PATCH] memcg-v1: Enable setting memory min, low, high Date: Wed, 5 Apr 2023 16:21:31 +0200 Message-ID: <2023040500-drinking-obvious-bd85@gregkh> References: <20230405110107.127156-1-shaun.tancheff@gmail.com> <2023040529-commodore-humongous-47c3@gregkh> Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1680704494; bh=eyBjOtC7CJFOS5X6Sp9ly9THlOS5XlccxmCOFpUhOl4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=bkToI3kjLCFkg/Q9XiT8E06SrfvrJtgXoZM39QA51VeWtLgANnUBE7hJ/ogxNxeOI ydJTjh3bdKT69RKz8iF1i+7JV4C9BaVRxmH+dqVKXlurRTsJCPinJ1tXHUEDS8Ui6G Qymz+m9pc6XZp6tnGjnOumjKfK6rAeR//gpPltw8= Content-Disposition: inline In-Reply-To: List-ID: Content-Type: text/plain; charset="windows-1252" To: Shaun Tancheff Cc: Johannes Weiner , Michal Hocko , Vladimir Davydov , Shaun Tancheff , Andrew Morton , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org On Wed, Apr 05, 2023 at 08:54:07PM +0700, Shaun Tancheff wrote: > On Wed, Apr 5, 2023 at 6:23=E2=80=AFPM Greg KH wrote: >=20 > > On Wed, Apr 05, 2023 at 06:01:07PM +0700, Shaun Tancheff wrote: > > > From: Shaun Tancheff > > > > > > For users that are unable to update to memcg-v2 this > > > provides a method where memcg-v1 can more effectively > > > apply enough memory pressure to effectively throttle > > > filesystem I/O or otherwise minimize being memcg oom > > > killed at the expense of reduced performance. > > > > > > This patch extends the memcg-v1 legacy sysfs entries > > > with: > > > limit_in_bytes.min, limit_in_bytes.low and > > > limit_in_bytes.high > > > Since old software will need to be updated to take > > > advantage of the new files a secondary method > > > of setting min, low and high based on a percentage > > > of the limit is also provided. The percentages > > > are determined by module parameters. > > > > > > The available module parameters can be set at > > > kernel boot time, for example: > > > memcontrol.memcg_min=3D10 > > > memcontrol.memcg_low=3D30 > > > memcontrol.memcg_high=3D80 > > > > > > Would set min to 10%, low to 30% and high to 80% of > > > the value written to: > > > /sys/fs/cgroup/memory//memory.limit_in_bytes > > > > > > Signed-off-by: Shaun Tancheff > > > --- > > > v0: Initial hard coded limits by percent. > > > v1: Added sysfs access and module parameters for percent values to en= able > > > v2: Fix 32-bit, remove need for missing __udivdi3 > > > mm/memcontrol.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++= +- > > > 1 file changed, 82 insertions(+), 1 deletion(-) > > > > > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > > > index 2eee092f8f11..3cf8386f4f45 100644 > > > --- a/mm/memcontrol.c > > > +++ b/mm/memcontrol.c > > > @@ -73,6 +73,18 @@ > > > > > > #include > > > > > > +static unsigned int memcg_v1_min_default_percent; > > > +module_param_named(memcg_min, memcg_v1_min_default_percent, uint, 06= 00); > > > +MODULE_PARM_DESC(memcg_min, "memcg v1 min default percent"); > > > + > > > +static unsigned int memcg_v1_low_default_percent; > > > +module_param_named(memcg_low, memcg_v1_low_default_percent, uint, 06= 00); > > > +MODULE_PARM_DESC(memcg_low, "memcg v1 low default percent"); > > > + > > > +static unsigned int memcg_v1_high_default_percent; > > > +module_param_named(memcg_high, memcg_v1_high_default_percent, uint, > > 0600); > > > +MODULE_PARM_DESC(memcg_high, "memcg v1 high default percent"); > > > > This is not the 1990's, why are you using module parameters for this? > > > And this isn't a module, so why use module options, how are you supposed > > to set them? > > > Ah .. guess I'm a bit out of date. > The can be set either on the kernel command line or through sysfs, > nominally > /sys/module/memcontrol/parameters/memcg_high > /sys/module/memcontrol/parameters/memcg_low > /sys/module/memcontrol/parameters/memcg_min But again, memcontrol is not a module, right? > I will look at making these sysctl values instead. Yeah, just stick with that please. thanks, greg k-h