linux-kernel - Re: [PATCH v1 0/4] Kill the time spent in patch

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Date:   Tue, 27 Sep 2022 14:38:25 +0000
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Benjamin Gray <bgray@...ux.ibm.com>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>
Subject: Re: [PATCH v1 0/4] Kill the time spent in patch_instruction()

Argh !! Looks like I sent an old already applied series nested in the 
new one.

Ignore those x/4 patches, only look at the x/6 ones.


Le 27/09/2022 à 16:33, Christophe Leroy a écrit :
> This series reduces by 70% the time required to activate
> ftrace on an 8xx with CONFIG_STRICT_KERNEL_RWX.
> 
> Measure is performed in function ftrace_replace_code() using mftb()
> around the loop.
> 
> With the series,
> - Without CONFIG_STRICT_KERNEL_RWX, 416000 TB ticks are measured.
> - With CONFIG_STRICT_KERNEL_RWX, 546000 TB ticks are measured.
> 
> Before this series,
> - Without CONFIG_STRICT_KERNEL_RWX, 427000 TB ticks are measured.
> - With CONFIG_STRICT_KERNEL_RWX, 1744000 TB ticks are measured.
> 
> Before the series, CONFIG_STRICT_KERNEL_RWX multiplies the time
> required for ftrace activation by more than 4.
> 
> With the series, CONFIG_STRICT_KERNEL_RWX increases the time
> required for ftrace activation by only 30%
> 
> Christophe Leroy (4):
>    powerpc/code-patching: Don't call is_vmalloc_or_module_addr() without
>      CONFIG_MODULES
>    powerpc/code-patching: Speed up page mapping/unmapping
>    powerpc/code-patching: Use jump_label for testing freed initmem
>    powerpc/code-patching: Use jump_label to check if poking_init() is
>      done
> 
>   arch/powerpc/include/asm/code-patching.h |  2 ++
>   arch/powerpc/lib/code-patching.c         | 37 +++++++++++++++---------
>   arch/powerpc/mm/mem.c                    |  2 ++
>   3 files changed, 28 insertions(+), 13 deletions(-)
>