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From: Matt Fleming <mfleming@cloudflare.com>
To: Marco Elver <elver@google.com>, Caleb Kan <calebkan1106@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org,  linux-kernel@vger.kernel.org,
	kasan-dev@googlegroups.com, Vlastimil Babka <vbabka@kernel.org>,
	 Alexander Potapenko <glider@google.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	 Andrey Konovalov <andreyknvl@gmail.com>,
	Oscar Salvador <osalvador@suse.de>,
	 Caleb Kan <ckan@cloudflare.com>,
	kernel-team@cloudflare.com
Subject: Re: [PATCH RFC v2 00/11] stackdepot: reduce memory use for persistent stack records with a trie
Date: Wed, 7 Oct 2026 11:34:04 +0100	[thread overview]
Message-ID: <asYc-sRxG6kyu5yh@matt-Precision-5490> (raw)
In-Reply-To: <20260908-stackdepot-trie-v2-0-1996d5cef732@cloudflare.com>

On Tue, Sep 08, 2026 at 02:13:33PM +0100, Caleb Kan wrote:
> Hi,
> 
> This series reduces the memory used by persistent stack depot records by
> sharing common frame prefixes in a path-compressed trie.
> 
> Cloudflare runs KASAN on pre-production servers so allocation and free
> stack traces are available when diagnosing memory-safety bugs. On some of
> these servers, stack depot exhausted its pool budget even after we raised
> stack_depot_max_pools from 8,192 to 32,768. Once the depot is full, a new
> persistent trace returns no handle and a later KASAN report can lose the
> history needed to explain the bug.
> 
> With 4 KiB pages, 32,768 order-2 pools allow 512 MiB of stack storage.
> Doubling the limit again would allow 1 GiB, but it would not change the
> linear growth: the hash backend shares identical complete traces, while
> two traces that differ by one frame are still stored independently.
> 
> The trie is opt-in and disabled by default.

Hey Marco,

Do you have any more feedback on this series? Particularly the bug fix
in patch 1?

Thanks,
Matt


      parent reply	other threads:[~2026-10-07 10:34 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-08 13:13 [PATCH RFC v2 00/11] stackdepot: reduce memory use for persistent stack records with a trie Caleb Kan
2026-09-08 13:13 ` [PATCH RFC v2 01/11] stackdepot: stop preallocating after the final pool Caleb Kan
2026-09-08 13:13 ` [PATCH RFC v2 02/11] stackdepot: add caller-owned stack trace fetching Caleb Kan
2026-09-08 13:13 ` [PATCH RFC v2 03/11] mm/page_owner: preserve accounting with countable stack depot records Caleb Kan
2026-09-08 13:13 ` [PATCH RFC v2 04/11] mm/kmemleak: print trie-backed stack depot traces Caleb Kan
2026-09-08 13:13 ` [PATCH RFC v2 05/11] kmsan: report " Caleb Kan
2026-09-08 13:13 ` [PATCH RFC v2 06/11] mm/slub: materialize " Caleb Kan
2026-09-08 13:13 ` [PATCH RFC v2 07/11] drm/locking: preserve deadlock diagnostics for trie-backed stacks Caleb Kan
2026-09-08 13:13 ` [PATCH RFC v2 08/11] scripts/gdb: reject trie-backed stack depot handles Caleb Kan
2026-09-08 13:13 ` [PATCH RFC v2 09/11] stackdepot: add architecture hooks for compact frame storage Caleb Kan
2026-09-08 13:13 ` [PATCH RFC v2 10/11] stackdepot: share persistent stack prefixes with trie storage Caleb Kan
2026-09-08 13:13 ` [PATCH RFC v2 11/11] stackdepot: add KUnit tests for " Caleb Kan
2026-10-07 10:34 ` Matt Fleming [this message]

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