Re: [failures] mm-vmalloc-print-a-warning-message-first-on-failure.patch removed from -mm tree

[Mel Gorman <mgorman@suse.de>]

On Fri, May 14, 2021 at 07:16:23PM +0200, Uladzislau Rezki wrote:
> > > See below an example of audio glitches. That was related to our phones
> > > and audio workloads:
> > > 
> > > # Explanation is here
> > > wget ftp://vps418301.ovh.net/incoming/analysis_audio_glitches.txt
> > > 
> > > # Audio 10 seconds sample is here.
> > > # The drop occurs at 00:09.295 you can hear it
> > > wget ftp://vps418301.ovh.net/incoming/tst_440_HZ_tmp_1.wav
> > > 
> > > Apart of that a slow allocation can course two type of issues. First one
> > > is direct. When for example a high-priority RT thread does some allocation
> > > to bypass data to DSP. Long latency courses a delay of data to be passed to
> > > DSP. This is drivers area.
> > > 
> > > Another example is when a task is doing an allocation and the RT task is
> > > placed onto a same CPU. In that case a long preemption-off(milliseconds)
> > > section can lead the RT task for starvation. For mobile devices it is UI
> > > stack where RT tasks are used. As a result we face frame drops.
> > > 
> > > All such issues have been solved after a rework:
> > > 
> > > wget ftp://vps418301.ovh.net/incoming/Reworking_of_KVA_allocator_in_Linux_kernel.pdf
> > > 
> > 
> > Thanks. That was enough for me to search to see what sort of general
> > workload would be affected. Mostly it's driver specific. A lot of the users
> > that would be potentially hot are already using kvmalloc so probably not
> > worth the effort so test_vmalloc.sh makes sense.
> > 
> You are welcome.
> 
> As for a helper. Does it sound good for you? BTW, once upon a time i had
> asked for it :)
> 

The intent was that instead of guessing in advance what APIs would be
needed that users would add an API helper where appropriate.

> From b4b0de2990defd43453ddcd2839521d117cb3bd9 Mon Sep 17 00:00:00 2001
> From: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
> Date: Fri, 14 May 2021 18:39:08 +0200
> Subject: [PATCH] mm/page_alloc: Add an alloc_pages_bulk_array_node() helper
> 
> Add a "node" variant of the alloc_pages_bulk_array() function.
> The helper guarantees that a __alloc_pages_bulk() is invoked
> with a valid NUMA node id.
> 
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>

Acked-by: Mel Gorman <mgorman@suse.de>

Include it as part of your series adding the vmalloc user.

-- 
Mel Gorman
SUSE Labs