From: Michal Hocko <mhocko@kernel.org>
To: Mike Christie <mchristi@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-scsi@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-block@vger.kernel.org, martin@urbackup.org,
Damien.LeMoal@wdc.com
Subject: Re: [PATCH] Add prctl support for controlling PF_MEMALLOC V2
Date: Wed, 23 Oct 2019 19:35:24 +0200 [thread overview]
Message-ID: <20191023173524.GM17610@dhcp22.suse.cz> (raw)
In-Reply-To: <5DB08D81.8050300@redhat.com>
On Wed 23-10-19 12:27:29, Mike Christie wrote:
> On 10/23/2019 02:11 AM, Michal Hocko wrote:
> > On Wed 23-10-19 07:43:44, Dave Chinner wrote:
> >> On Tue, Oct 22, 2019 at 06:33:10PM +0200, Michal Hocko wrote:
> >
> > Thanks for more clarifiation regarding PF_LESS_THROTTLE.
> >
> > [...]
> >>> PF_IO_FLUSHER would mean that the user
> >>> context is a part of the IO path and therefore there are certain reclaim
> >>> recursion restrictions.
> >>
> >> If PF_IO_FLUSHER just maps to PF_LESS_THROTTLE|PF_MEMALLOC_NOIO,
> >> then I'm not sure we need a new definition. Maybe that's the ptrace
> >> flag name, but in the kernel we don't need a PF_IO_FLUSHER process
> >> flag...
> >
> > Yes, the internal implementation would do something like that. I was
> > more interested in the user space visible API at this stage. Something
> > generic enough because exporting MEMALLOC flags is just a bad idea IMHO
> > (especially PF_MEMALLOC).
>
> Do you mean we would do something like:
>
> prctl()
> ....
> case PF_SET_IO_FLUSHER:
> current->flags |= PF_MEMALLOC_NOIO;
> ....
yes, along with PF_LESS_THROTTLE.
--
Michal Hocko
SUSE Labs
prev parent reply other threads:[~2019-10-23 17:35 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-21 21:41 [PATCH] Add prctl support for controlling PF_MEMALLOC V2 Mike Christie
2019-10-21 22:52 ` Dave Chinner
2019-10-22 15:42 ` Mike Christie
2019-10-22 11:24 ` Michal Hocko
2019-10-22 16:13 ` Mike Christie
2019-10-22 16:33 ` Michal Hocko
2019-10-22 20:43 ` Dave Chinner
2019-10-23 7:11 ` Michal Hocko
2019-10-23 17:27 ` Mike Christie
2019-10-23 17:35 ` Michal Hocko [this message]
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