From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Mark Brown <broonie@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org,
"Paul E. McKenney" <paulmck@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Dennis Zhou <dennis@kernel.org>, Tejun Heo <tj@kernel.org>,
Christoph Lameter <cl@linux.com>,
Martin Liu <liumartin@google.com>,
David Rientjes <rientjes@google.com>,
christian.koenig@amd.com, Shakeel Butt <shakeel.butt@linux.dev>,
SeongJae Park <sj@kernel.org>, Michal Hocko <mhocko@suse.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Sweet Tea Dorminy <sweettea-kernel@dorminy.me>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
"Liam R . Howlett" <liam.howlett@oracle.com>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Vlastimil Babka <vbabka@suse.cz>,
Christian Brauner <brauner@kernel.org>,
Wei Yang <richard.weiyang@gmail.com>,
David Hildenbrand <david@redhat.com>,
Miaohe Lin <linmiaohe@huawei.com>,
Al Viro <viro@zeniv.linux.org.uk>,
linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org,
Yu Zhao <yuzhao@google.com>,
Roman Gushchin <roman.gushchin@linux.dev>,
Mateusz Guzik <mjguzik@gmail.com>,
Matthew Wilcox <willy@infradead.org>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
Aboorva Devarajan <aboorvad@linux.ibm.com>,
Aishwarya TCV <Aishwarya.TCV@arm.com>
Subject: Re: [PATCH v10 2/3] mm: Fix OOM killer inaccuracy on large many-core systems
Date: Fri, 19 Dec 2025 11:01:11 -0500 [thread overview]
Message-ID: <2fb78e41-5e56-425f-925f-a29524355d2c@efficios.com> (raw)
In-Reply-To: <2a772584-2269-4008-809a-6123e226ebe3@sirena.org.uk>
On 2025-12-19 04:31, Mark Brown wrote:
> On Thu, Dec 18, 2025 at 05:18:04PM -0500, Mathieu Desnoyers wrote:
>> On 2025-12-18 13:00, Mark Brown wrote:
>
>> An ugly work-around that may work (and then we can improve on this),
>> at the end of mm/init-mm.c:init_mm (completely untested):
>
>> .cpu_bitmap = { [0 ... ((3*BITS_TO_LONGS(NR_CPUS))-1 + ((69905 * NR_MM_COUNTERS * 64) / BYTES_PER_LONG))] = 0UL },
>
> That doesn't seem to fix the FVP unfortunately (BYTES_PER_LONG doesn't
> exist, but even just deleting the division entirely fails in the same
> way).
I just noticed that there is another static instance of mm_struct:
drivers/firmware/efi/efi.c struct mm_struct efi_mm
we need to apply the same fix to it as well. It seems to fit
with the currently running task when the oops happens:
[ 2.482454] CPU: 2 UID: 0 PID: 12 Comm: kworker/u32:0 Not tainted 6.19.0-rc1-next-20251218 #1 PREEMPT
[ 2.482609] Workqueue: efi_rts_wq efi_call_rts
[...]
[ 2.485094] acct_account_cputime+0x40/0xa4 (P)
[...]
[ 2.487172] el1h_64_irq+0x6c/0x70
[...]
[ 2.487853] __efi_rt_asm_wrapper+0x50/0x74
Thanks,
Mathieu
--
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com
next prev parent reply other threads:[~2025-12-19 16:01 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20251213185608.3418096-1-mathieu.desnoyers@efficios.com>
2025-12-13 18:56 ` [PATCH v10 1/3] lib: Introduce hierarchical per-cpu counters Mathieu Desnoyers
2025-12-13 18:56 ` [PATCH v10 2/3] mm: Fix OOM killer inaccuracy on large many-core systems Mathieu Desnoyers
2025-12-18 18:00 ` Mark Brown
2025-12-18 22:18 ` Mathieu Desnoyers
2025-12-19 9:31 ` Mark Brown
2025-12-19 16:01 ` Mathieu Desnoyers [this message]
2025-12-13 18:56 ` [PATCH v10 3/3] mm: Implement precise OOM killer task selection Mathieu Desnoyers
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