Re: [PATCH] Add prctl support for controlling mem reclaim V4

[Christian Brauner <christian.brauner@ubuntu.com>]

On Mon, Jan 27, 2020 at 02:02:59PM +0100, Christian Brauner wrote:
> On Sat, Jan 25, 2020 at 08:16:42AM +1100, Dave Chinner wrote:
> > On Fri, Jan 24, 2020 at 10:22:33AM -0600, Mike Christie wrote:
> > > On 12/05/2019 04:43 PM, Shakeel Butt wrote:
> > > > On Mon, Nov 11, 2019 at 4:19 PM Mike Christie <mchristi@redhat.com> wrote:
> > > >> This patch adds a new prctl command that daemons can use after they have
> > > >> done their initial setup, and before they start to do allocations that
> > > >> are in the IO path. It sets the PF_MEMALLOC_NOIO and PF_LESS_THROTTLE
> > > >> flags so both userspace block and FS threads can use it to avoid the
> > > >> allocation recursion and try to prevent from being throttled while
> > > >> writing out data to free up memory.
> > > >>
> > > >> Signed-off-by: Mike Christie <mchristi@redhat.com>
> > > >> Acked-by: Michal Hocko <mhocko@suse.com>
> > > >> Tested-by: Masato Suzuki <masato.suzuki@wdc.com>
> > > >> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
> > > > 
> > > > I suppose this patch should be routed through MM tree, so, CCing Andrew.
> > > >
> > > 
> > > Andrew and other mm/storage developers,
> > > 
> > > Do I need to handle anything else for this patch, or are there any other
> > > concerns? Is this maybe something we want to talk about at a quick LSF
> > > session?
> > > 
> > > I have retested it with Linus's current tree. It still applies cleanly
> > > (just some offsets), and fixes the problem described above we have been
> > > hitting.
> > 
> > I must have missed this version being posted (just looked it up on
> > lore.kernel.org). As far as I'm concerned this is good to go and it
> > is absolutely necessary for userspace IO stacks to function
> > correctly.
> > 
> > Reviewed-by: Dave Chinner <dchinner@redhat.com>
> > 
> > If no manintainer picks it up before the next merge window, then I
> 
> Since prctl() is thread-management and fs people seem to be happy and
> have acked it I can pick this up too if noone objects and send this
> along with the rest of process management.

This is upstream now
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8d19f1c8e1937baf74e1962aae9f90fa3aeab463

Christian