linux-kernel - Re: [PATCH 3/3] mm/percpu.c: print error message too if atomic alloc failed

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Message-ID: <ZLryhIzyDUpEPUzT@snowbird>
Date:   Fri, 21 Jul 2023 14:03:00 -0700
From:   Dennis Zhou <dennis@...nel.org>
To:     Baoquan He <bhe@...hat.com>
Cc:     linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        akpm@...ux-foundation.org, tj@...nel.org, cl@...ux.com,
        mawupeng1@...wei.com
Subject: Re: [PATCH 3/3] mm/percpu.c: print error message too if atomic alloc
 failed

On Fri, Jul 21, 2023 at 09:18:00PM +0800, Baoquan He wrote:
> The variable 'err' is assgigned to an error message if atomic alloc
> failed, while it has no chance to be printed if is_atomic is true.
> 
> Here change to print error message too if atomic alloc failed, while
> avoid to call dump_stack() if that case.
> 
> Signed-off-by: Baoquan He <bhe@...hat.com>
> ---
>  mm/percpu.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/percpu.c b/mm/percpu.c
> index c25b058a46ad..74f75ef0ad58 100644
> --- a/mm/percpu.c
> +++ b/mm/percpu.c
> @@ -1890,13 +1890,15 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved,
>  fail:
>  	trace_percpu_alloc_percpu_fail(reserved, is_atomic, size, align);
>  
> -	if (!is_atomic && do_warn && warn_limit) {
> +	if (do_warn && warn_limit) {
>  		pr_warn("allocation failed, size=%zu align=%zu atomic=%d, %s\n",
>  			size, align, is_atomic, err);
> -		dump_stack();
> +		if (is_atomic)
> +			dump_stack();

This should be (!is_atomic) to preserve the current logic?

>  		if (!--warn_limit)
>  			pr_info("limit reached, disable warning\n");
>  	}
> +
>  	if (is_atomic) {
>  		/* see the flag handling in pcpu_balance_workfn() */
>  		pcpu_atomic_alloc_failed = true;
> -- 
> 2.34.1
> 

Thanks,
Dennis