linux-kernel - Re: [PATCH v2] alloc_tag: handle incomplete bulk allocations in vm_module_tags

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Message-ID: <CAJuCfpHaocOVHf673X1nn_R0cpz=GtDZEZ+ceo+5OptRcBUjcw@mail.gmail.com>
Date: Thu, 10 Apr 2025 01:44:00 +0000
From: Suren Baghdasaryan <surenb@...gle.com>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: "T.J. Mercier" <tjmercier@...gle.com>, kent.overstreet@...ux.dev, 
	janghyuck.kim@...sung.com, linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] alloc_tag: handle incomplete bulk allocations in vm_module_tags_populate

On Thu, Apr 10, 2025 at 12:12 AM Andrew Morton
<akpm@...ux-foundation.org> wrote:
>
> On Wed,  9 Apr 2025 22:51:11 +0000 "T.J. Mercier" <tjmercier@...gle.com> wrote:
>
> > alloc_pages_bulk_node may partially succeed and allocate fewer than the
> > requested nr_pages. There are several conditions under which this can
> > occur, but we have encountered the case where CONFIG_PAGE_OWNER is
> > enabled causing all bulk allocations to always fallback to single page
> > allocations due to commit 187ad460b841 ("mm/page_alloc: avoid page
> > allocator recursion with pagesets.lock held").
> >
> > Currently vm_module_tags_populate immediately fails when
> > alloc_pages_bulk_node returns fewer than the requested number of pages.
> > When this happens memory allocation profiling gets disabled, for example
> >
> > [   14.297583] [9:       modprobe:  465] Failed to allocate memory for allocation tags in the module scsc_wlan. Memory allocation profiling is disabled!
> > [   14.299339] [9:       modprobe:  465] modprobe: Failed to insmod '/vendor/lib/modules/scsc_wlan.ko' with args '': Out of memory
> >
> > This patch causes vm_module_tags_populate to retry bulk allocations for
> > the remaining memory instead of failing immediately which will avoid the
> > disablement of memory allocation profiling.
> >
>
> Thanks.  I'm assuming we want cc:stable on this?
>
> btw, it looks like the "Clean up and error out" code in
> vm_module_tags_populate() could use release_pages().

True. I'll add that into my TODO list. Thanks!

>