Fwd: [PATCH] mm: add config option to select the initial overcommit mode

Hi,

Using checkpatch.pl on the forwarded patch results in:

WARNING: please write a paragraph that describes the config symbol fully
torvalds#57: FILE: mm/Kconfig:451:
+       config OVERCOMMIT_GUESS

WARNING: please write a paragraph that describes the config symbol fully
torvalds#64: FILE: mm/Kconfig:458:
+       config OVERCOMMIT_ALWAYS

but there is a 'help' section for those 'config' sections.
NOTE: I followed the same indentation than the code laying just above the place where I inserted mine.

I think it is a false positive, what do you think?

Best regards,

Sebastian

Message-ID: <5731CC6E.3080807@laposte.net>
Date: Tue, 10 May 2016 13:56:30 +0200
From: Sebastian Frias <sf84@laposte.net>
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0
To: <linux-mm@kvack.org>, Andrew Morton <akpm@linux-foundation.org>, "Michal
 Hocko" <mhocko@suse.com>, Linus Torvalds <torvalds@linux-foundation.org>
CC: LKML <linux-kernel@vger.kernel.org>, mason <slash.tmp@free.fr>
Subject: [PATCH] mm: add config option to select the initial overcommit mode
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Currently the initial value of the overcommit mode is OVERCOMMIT_GUESS.
However, on embedded systems it is usually better to disable overcommit
to avoid waking up the OOM-killer and its well known undesirable
side-effects.

This config option allows to setup the initial overcommit mode to any of
the 3 available values, OVERCOMMIT_GUESS (which remains as default),
OVERCOMMIT_ALWAYS and OVERCOMMIT_NEVER.
The overcommit mode can still be changed thru sysctl after the system
boots up.

This config option depends on CONFIG_EXPERT.
This patch does not introduces functional changes.

Signed-off-by: Sebastian Frias <sf84@laposte.net>

mm/Kconfig

@@ -427,6 +427,38 @@ choice
  benefit.
 endchoice
 
+choice
+ prompt "Overcommit Mode"
+ default OVERCOMMIT_GUESS
+ depends on EXPERT
+ help
+ Selects the initial value for Overcommit mode.
+
+ NOTE: The overcommit mode can be changed dynamically through sysctl.
+
+ config OVERCOMMIT_GUESS
+ bool "Guess"
+ help
+ Selecting this option forces the initial value of overcommit mode to
+ "Guess" overcommits. This is the default value.
+ See Documentation/vm/overcommit-accounting for more information.
+
+ config OVERCOMMIT_ALWAYS
+ bool "Always"
+ help
+ Selecting this option forces the initial value of overcommit mode to
+ "Always" overcommit.
+ See Documentation/vm/overcommit-accounting for more information.
+
+ config OVERCOMMIT_NEVER
+ bool "Never"
+ help
+ Selecting this option forces the initial value of overcommit mode to
+ "Never" overcommit.
+ See Documentation/vm/overcommit-accounting for more information.
+
+endchoice
+
 #
 # UP and nommu archs use km based percpu allocator
 #

mm/util.c

@@ -394,7 +394,13 @@ int __page_mapcount(struct page *page)
 }
 EXPORT_SYMBOL_GPL(__page_mapcount);
 
+#if defined(CONFIG_OVERCOMMIT_NEVER)
+int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_NEVER;
+#elif defined(CONFIG_OVERCOMMIT_ALWAYS)
+int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_ALWAYS;
+#else
 int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS;
+#endif
 int sysctl_overcommit_ratio __read_mostly = 50;
 unsigned long sysctl_overcommit_kbytes __read_mostly;
 int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;