From: Arnd Bergmann <arnd@arndb.de>
To: Jason Baron <jbaron@akamai.com>
Cc: akpm@linux-foundation.org, joe@perches.com, peterz@infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 4/4] dynamic_debug: add jump label support
Date: Fri, 10 Jun 2016 11:54:03 +0200 [thread overview]
Message-ID: <3796097.4dlb9d7Id8@wuerfel> (raw)
In-Reply-To: <587263b37406eda0d2ab84874a9fd4c81eaeca1d.1463778029.git.jbaron@akamai.com>
On Friday, May 20, 2016 5:16:36 PM CEST Jason Baron wrote:
> Although dynamic debug is often only used for debug builds, sometimes its
> enabled for production builds as well. Minimize its impact by using jump
> labels. This reduces the text section by 7000+ bytes in the kernel image
> below. It does increase data, but this should only be referenced when
> changing the direction of the branches, and hence usually not in cache.
>
> text data bss dec hex filename
> 8194852 4879776 925696 14000324 d5a0c4 vmlinux.pre
> 8187337 4960224 925696 14073257 d6bda9 vmlinux.post
>
> Signed-off-by: Jason Baron <jbaron@akamai.com>
> ---
This causes problems for some of my randconfig builds, when a dynamic
debug call is used inside of an __exit function:
`.exit.text' referenced in section `__jump_table' of drivers/built-in.o: defined in discarded section `.exit.text' of drivers/built-in.o
`.exit.text' referenced in section `__jump_table' of drivers/built-in.o: defined in discarded section `.exit.text' of drivers/built-in.o
Arnd
next prev parent reply other threads:[~2016-06-10 9:53 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-20 21:16 [PATCH v2 0/4] convert dynamic_debug to use jump labels Jason Baron
2016-05-20 21:16 ` [PATCH v2 1/4] jump_label: remove bug.h, atomic.h dependencies for HAVE_JUMP_LABEL Jason Baron
2016-05-20 21:16 ` [PATCH v2 2/4] powerpc: add explicit #include <asm/asm-compat.h> for jump label Jason Baron
2016-05-20 21:16 ` [PATCH v2 3/4] s390: add explicit <linux/stringify.h> " Jason Baron
2016-05-20 21:16 ` [PATCH v2 4/4] dynamic_debug: add jump label support Jason Baron
2016-06-10 9:54 ` Arnd Bergmann [this message]
2016-06-10 15:33 ` Jason Baron
2016-06-13 16:05 ` Arnd Bergmann
2016-06-13 20:23 ` Arnd Bergmann
2016-06-13 20:32 ` Jason Baron
2016-07-01 20:45 ` Arnd Bergmann
[not found] ` <5786613E.6010509@akamai.com>
2016-07-13 16:03 ` Arnd Bergmann
2016-06-10 21:28 ` Jason Baron
2016-07-01 19:30 ` Chris Metcalf
2016-07-05 20:57 ` Jason Baron
2016-07-06 16:52 ` Chris Metcalf
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