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

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Message-Id: <20250409171238.494fd49979b4607bff9791b7@linux-foundation.org>
Date: Wed, 9 Apr 2025 17:12:38 -0700
From: Andrew Morton <akpm@...ux-foundation.org>
To: "T.J. Mercier" <tjmercier@...gle.com>
Cc: surenb@...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 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().