From: Andrew Morton <akpm@linux-foundation.org>
To: gaoxu <gaoxu2@honor.com>
Cc: Dennis Zhou <dennis@kernel.org>, Tejun Heo <tj@kernel.org>,
Christoph Lameter <cl@linux.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"surenb@google.com" <surenb@google.com>,
yipengxiang <yipengxiang@honor.com>
Subject: Re: mm: percpu: increase PERCPU_MODULE_RESERVE to avoid allocation failure
Date: Tue, 22 Apr 2025 17:02:09 -0700 [thread overview]
Message-ID: <20250422170209.a8beaa8a3610d2e92421476f@linux-foundation.org> (raw)
In-Reply-To: <bcfb90b2cecf43d7a0760ebaddde10d8@honor.com>
On Tue, 22 Apr 2025 11:39:30 +0000 gaoxu <gaoxu2@honor.com> wrote:
> In android16-6.12, enabling CONFIG_MEM_ALLOC_PROFILING causes some modules
> to fail to load during boot because of failed percpu memory allocation.
Which modules? If they're in-tree modules then we should fix this
issue in -stable kernels also.
If they're out-of-tree modules then what argument is there for altering
the mainline kernel?
> [811:modprobe]percpu: allocation failed, size=5200 align=8 atomic=0, alloc
> from reserved chunk failed
> [811:modprobe]Call trace:
> [811:modprobe] dump_backtrace+0xfc/0x17c
> [811:modprobe] show_stack+0x18/0x28
> [811:modprobe] dump_stack_lvl+0x40/0xc0
> [811:modprobe] dump_stack+0x18/0x24
> [811:modprobe] pcpu_alloc_noprof+0x96c/0xb58
> [811:modprobe] percpu_modalloc+0x50/0xec
> [811:modprobe] load_module+0x1158/0x153c
> [811:modprobe] __arm64_sys_finit_module+0x23c/0x340
> [811:modprobe] invoke_syscall+0x58/0x10c
> [811:modprobe] el0_svc_common+0xa8/0xdc
> [811:modprobe] do_el0_svc+0x1c/0x28
> [811:modprobe] el0_svc+0x40/0x90
> [811:modprobe] el0t_64_sync_handler+0x70/0xbc
> [811:modprobe] el0t_64_sync+0x1a8/0x1ac
> [811:modprobe]ipam: Could not allocate 5200 bytes percpu data
>
> Increase PERCPU_MODULE_RESERVE to resolve this issue.
>
> ...
>
> --- a/include/linux/percpu.h
> +++ b/include/linux/percpu.h
> @@ -16,7 +16,7 @@
> /* enough to cover all DEFINE_PER_CPUs in modules */
> #ifdef CONFIG_MODULES
> #ifdef CONFIG_MEM_ALLOC_PROFILING
> -#define PERCPU_MODULE_RESERVE (8 << 13)
> +#define PERCPU_MODULE_RESERVE (8 << 14)
> #else
> #define PERCPU_MODULE_RESERVE (8 << 10)
> #endif
PERCPU_MODULE_RESERVE is a pretty unpleasant thing. It appears that it
gives us the choice between either wasting memory or failing module
loading. But I expect that something more dynamic would be a ton of work.
next prev parent reply other threads:[~2025-04-23 0:02 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-22 11:39 gaoxu
2025-04-23 0:02 ` Andrew Morton [this message]
2025-04-23 0:19 ` Suren Baghdasaryan
2025-04-23 15:12 ` Tejun Heo
2025-04-23 17:04 ` Suren Baghdasaryan
2025-04-23 1:17 ` Dennis Zhou
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