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From: Chris Mason <clm@meta.com>
To: Vlastimil Babka <vbabka@suse.cz>,
	Roman Gushchin <roman.gushchin@linux.dev>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Christoph Lameter <cl@gentwo.org>,
	David Rientjes <rientjes@google.com>,
	Harry Yoo <harry.yoo@oracle.com>,
	Uladzislau Rezki <urezki@gmail.com>,
	"Liam R. Howlett" <Liam.Howlett@oracle.com>,
	Suren Baghdasaryan <surenb@google.com>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Alexei Starovoitov <ast@kernel.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	linux-rt-devel@lists.linux.dev, bpf@vger.kernel.org,
	kasan-dev@googlegroups.com, Petr Tesarik <ptesarik@suse.com>,
	"Paul E . McKenney" <paulmck@kernel.org>
Subject: Re: [PATCH RFC 10/19] slab: remove cpu (partial) slabs usage from allocation paths
Date: Mon, 12 Jan 2026 09:36:25 -0500	[thread overview]
Message-ID: <a4b0be3f-bb6f-42d7-9176-a2bc0dcbd3a8@meta.com> (raw)
In-Reply-To: <01cf95d7-4e38-43c6-80ef-c990f66f1e26@suse.cz>

On 1/10/26 10:41 AM, Vlastimil Babka wrote:
> On 1/10/26 14:20, Chris Mason wrote:
>> On 1/9/26 3:16 AM, Vlastimil Babka wrote:
>>> On 10/24/25 16:29, Chris Mason wrote:
>>>> On Thu, 23 Oct 2025 15:52:32 +0200 Vlastimil Babka <vbabka@suse.cz> wrote:
>>
>> [ ... ]
>>
>>> By the way, there was another bug in this patch, causing a severe memory
>>> leak, which the AI unfortunately didn't flag. Petr reported it during
>>> performance testing and it took me more than a day to find it. Oh well :)
>>>
>>> Wonder if things got better since then perhaps, and your or Roman's tools
>>> would find it today? :)
>>
>> Yes and no.  It didn't find the leak until I changed the prompt to say:
>> "there is a leak, find it".  I'll see if I can improve things...
> 
> Thanks. Hmm even if it has to be done like this, it could be a substantial
> time saver vs finding the leak myself.

Finding the missing break on the first pass was tricky because claude
consistently focused on concerns about potential NULL pointers and
mostly ignored the loop flow control changes.

I think I've fixed things by expanding the loop analysis and also
forcing it to make a more fine grained list of changes to analyze before
it jumps into the review.

It caught the missing break 5 out of 6 times in a loop, so maybe?
That's probably the best I can get right now for a generic review, but
claude will almost always be more reliable with extra directions like
"there is a leak, find it" on top of the review prompt.

I've pushed out two new commits to:
https://github.com/masoncl/review-prompts

9a44c271 CS-001.md: pay more attention to loop control flow and memory
allocations
7fad3996 review-core.md: make change categories more fine grained

Thanks for flagging this, I think/hope it'll handle complex changes more
effectively now across the board.

-chris


  reply	other threads:[~2026-01-12 14:37 UTC|newest]

Thread overview: 72+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-23 13:52 [PATCH RFC 00/19] slab: replace cpu (partial) slabs with sheaves Vlastimil Babka
2025-10-23 13:52 ` [PATCH RFC 01/19] slab: move kfence_alloc() out of internal bulk alloc Vlastimil Babka
2025-10-23 15:20   ` Marco Elver
2025-10-29 14:38     ` Vlastimil Babka
2025-10-29 15:30       ` Marco Elver
2025-10-23 13:52 ` [PATCH RFC 02/19] slab: handle pfmemalloc slabs properly with sheaves Vlastimil Babka
2025-10-24 14:21   ` Chris Mason
2025-10-29 15:00     ` Vlastimil Babka
2025-10-29 16:06       ` Chris Mason
2025-10-23 13:52 ` [PATCH RFC 03/19] slub: remove CONFIG_SLUB_TINY specific code paths Vlastimil Babka
2025-10-24 22:34   ` Alexei Starovoitov
2025-10-29 15:37     ` Vlastimil Babka
2025-10-23 13:52 ` [PATCH RFC 04/19] slab: prevent recursive kmalloc() in alloc_empty_sheaf() Vlastimil Babka
2025-10-23 13:52 ` [PATCH RFC 05/19] slab: add sheaves to most caches Vlastimil Babka
2025-10-27  0:24   ` Harry Yoo
2025-10-29 15:42     ` Vlastimil Babka
2025-10-23 13:52 ` [PATCH RFC 06/19] slab: introduce percpu sheaves bootstrap Vlastimil Babka
2025-10-24 15:29   ` Chris Mason
2025-10-29 15:51     ` Vlastimil Babka
2025-12-15 12:17   ` Hao Li
2025-12-15 15:20     ` Vlastimil Babka
2025-10-23 13:52 ` [PATCH RFC 07/19] slab: make percpu sheaves compatible with kmalloc_nolock()/kfree_nolock() Vlastimil Babka
2025-10-24 14:04   ` Chris Mason
2025-10-29 17:30     ` Vlastimil Babka
2025-10-24 19:43   ` Alexei Starovoitov
2025-10-29 17:46     ` Vlastimil Babka
2025-10-23 13:52 ` [PATCH RFC 08/19] slab: handle kmalloc sheaves bootstrap Vlastimil Babka
2025-10-27  6:12   ` Harry Yoo
2025-10-29 20:06     ` Vlastimil Babka
2025-10-29 20:06       ` Vlastimil Babka
2025-10-30  0:11         ` Harry Yoo
2025-10-23 13:52 ` [PATCH RFC 09/19] slab: add optimized sheaf refill from partial list Vlastimil Babka
2025-10-27  7:20   ` Harry Yoo
2025-10-27  9:11     ` Harry Yoo
2025-10-29 20:48     ` Vlastimil Babka
2025-10-30  0:07       ` Harry Yoo
2025-10-30 13:18         ` Vlastimil Babka
2025-10-23 13:52 ` [PATCH RFC 10/19] slab: remove cpu (partial) slabs usage from allocation paths Vlastimil Babka
2025-10-24 14:29   ` Chris Mason
2025-10-29 21:31     ` Vlastimil Babka
2026-01-09  8:16     ` Vlastimil Babka
2026-01-10 13:20       ` Chris Mason
2026-01-10 15:41         ` Vlastimil Babka
2026-01-12 14:36           ` Chris Mason [this message]
2026-01-13 18:51             ` Roman Gushchin
2025-10-30  4:32   ` Harry Yoo
2025-10-30 13:09     ` Vlastimil Babka
2025-10-30 15:27       ` Alexei Starovoitov
2025-10-30 15:35         ` Vlastimil Babka
2025-10-30 15:59           ` Alexei Starovoitov
2025-11-03  3:44           ` Harry Yoo
2025-10-23 13:52 ` [PATCH RFC 11/19] slab: remove SLUB_CPU_PARTIAL Vlastimil Babka
2025-10-24 20:43   ` Alexei Starovoitov
2025-10-29 22:31     ` Vlastimil Babka
2025-10-30  0:26       ` Alexei Starovoitov
2025-10-23 13:52 ` [PATCH RFC 12/19] slab: remove the do_slab_free() fastpath Vlastimil Babka
2025-10-24 22:32   ` Alexei Starovoitov
2025-10-29 22:44     ` Vlastimil Babka
2025-10-30  0:24       ` Alexei Starovoitov
2025-10-23 13:52 ` [PATCH RFC 13/19] slab: remove defer_deactivate_slab() Vlastimil Babka
2025-10-23 13:52 ` [PATCH RFC 14/19] slab: simplify kmalloc_nolock() Vlastimil Babka
2025-12-16  2:35   ` Hao Li
2026-01-09 10:11     ` Vlastimil Babka
2026-01-09 11:48       ` Hao Li
2025-10-23 13:52 ` [PATCH RFC 15/19] slab: remove struct kmem_cache_cpu Vlastimil Babka
2025-10-23 13:52 ` [PATCH RFC 16/19] slab: remove unused PREEMPT_RT specific macros Vlastimil Babka
2025-10-23 13:52 ` [PATCH RFC 17/19] slab: refill sheaves from all nodes Vlastimil Babka
2025-10-23 13:52 ` [PATCH RFC 18/19] slab: update overview comments Vlastimil Babka
2025-10-23 13:52 ` [PATCH RFC 19/19] slab: remove frozen slab checks from __slab_free() Vlastimil Babka
2025-10-24 23:57 ` [PATCH RFC 00/19] slab: replace cpu (partial) slabs with sheaves Alexei Starovoitov
2025-11-04 22:11 ` Christoph Lameter (Ampere)
2026-01-12 10:55   ` Vlastimil Babka

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