From: Michal Hocko <mhocko@kernel.org>
To: Joe Perches <joe@perches.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] mm/page_alloc: Avoid KERN_CONT uses in warn_alloc
Date: Tue, 7 Nov 2017 13:50:55 +0100 [thread overview]
Message-ID: <20171107125055.cl5pyp2zwon44x5l@dhcp22.suse.cz> (raw)
In-Reply-To: <b31236dfe3fc924054fd7842bde678e71d193638.1509991345.git.joe@perches.com>
On Mon 06-11-17 10:02:56, Joe Perches wrote:
> KERN_CONT/pr_cont uses should be avoided where possible.
> Use single pr_warn calls instead.
>
> Signed-off-by: Joe Perches <joe@perches.com>
> ---
> mm/page_alloc.c | 14 ++++++--------
> 1 file changed, 6 insertions(+), 8 deletions(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 536431bf0f0c..82e6d2c914ab 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -3275,19 +3275,17 @@ void warn_alloc(gfp_t gfp_mask, nodemask_t *nodemask, const char *fmt, ...)
> if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs))
> return;
>
> - pr_warn("%s: ", current->comm);
> -
> va_start(args, fmt);
> vaf.fmt = fmt;
> vaf.va = &args;
> - pr_cont("%pV", &vaf);
> - va_end(args);
> -
> - pr_cont(", mode:%#x(%pGg), nodemask=", gfp_mask, &gfp_mask);
> if (nodemask)
> - pr_cont("%*pbl\n", nodemask_pr_args(nodemask));
> + pr_warn("%s: %pV, mode:%#x(%pGg), nodemask=%*pbl\n",
> + current->comm, &vaf, gfp_mask, &gfp_mask,
> + nodemask_pr_args(nodemask));
> else
> - pr_cont("(null)\n");
> + pr_warn("%s: %pV, mode:%#x(%pGg), nodemask=(null)\n",
> + current->comm, &vaf, gfp_mask, &gfp_mask);
> + va_end(args);
>
> cpuset_print_current_mems_allowed();
I do not like the duplication. It just calls for inconsistencies over
time. Can we instead make %*pbl consume NULL nodemask instead?
Something like the following pseudo patch + the if/else removed.
If this would be possible we could simplify other code as well I think
(at least oom code has to special case NULL nodemask).
What do you think?
---
diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h
index de1c50b93c61..106fac744f49 100644
--- a/include/linux/nodemask.h
+++ b/include/linux/nodemask.h
@@ -104,7 +104,7 @@ extern nodemask_t _unused_nodemask_arg_;
*
* Can be used to provide arguments for '%*pb[l]' when printing a nodemask.
*/
-#define nodemask_pr_args(maskp) MAX_NUMNODES, (maskp)->bits
+#define nodemask_pr_args(maskp) MAX_NUMNODES, (maskp) ? (maskp)->bits : NULL
/*
* The inline keyword gives the compiler room to decide to inline, or
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 1746bae94d41..6f40cf319a76 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -902,6 +902,9 @@ char *bitmap_list_string(char *buf, char *end, unsigned long *bitmap,
int cur, rbot, rtop;
bool first = true;
+ if (!bitmap)
+ return buf;
+
/* reused to print numbers */
spec = (struct printf_spec){ .base = 10 };
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2017-11-07 12:50 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-06 18:02 [PATCH] mm/page_alloc: Avoid KERN_CONT uses in warn_alloc Joe Perches
2017-11-07 12:50 ` Michal Hocko [this message]
2017-11-07 15:34 ` Joe Perches
2017-11-07 15:43 ` Michal Hocko
2017-11-07 16:03 ` Joe Perches
2017-11-09 10:05 ` Michal Hocko
2017-11-09 15:49 ` Joe Perches
2017-11-09 16:03 ` Michal Hocko
2017-11-09 16:27 ` Joe Perches
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