linux-kernel - Re: [PATCH v2] x86/head64: micro optimization: use memset instead of for loop

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Message-ID: <20160209131838.GA22486@gmail.com>
Date:	Tue, 9 Feb 2016 14:18:38 +0100
From:	Ingo Molnar <mingo@...nel.org>
To:	Alexander Kuleshov <kuleshovmail@...il.com>
Cc:	Ingo Molnar <mingo@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	"H . Peter Anvin" <hpa@...or.com>,
	Andrey Ryabinin <ryabinin.a.a@...il.com>,
	Andy Lutomirski <luto@...nel.org>,
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
	Alexander Popov <alpopov@...ecurity.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] x86/head64: micro optimization: use memset instead of
 for loop


* Alexander Kuleshov <kuleshovmail@...il.com> wrote:

> This patch simplifies clearing of page table directories, by
> the using of the fast memset() from the arch/x86/lib/memset_64.S.
> Besides this, we 25 bytes is 25 bytes less than original.
> 
> text       data     bss              dec            hex filename
> 
> 9735144 4970776 15474688        30180608        1cc8500 vmlinux.old
> 9735119 4970776 15474688        30180583        1cc84e7 vmlinux
> 
> Signed-off-by: Alexander Kuleshov <kuleshovmail@...il.com>
> ---
> Changelog:
> 
> v2: We got sizeof pud_p/pmd_p in the v1, but actually we need
> to take sizeof of pud_p/pmd_p pointer, although their sizes are
> the same.

Please send a delta patch (with changelog) as the v1 commit is already deep within 
the tip:x86/boot branch.

Thanks,

	Ingo