linux-kernel - Re: [PATCH 3/4] x86: Rewrite switch

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Date:	Tue, 14 Jun 2016 18:31:18 -0700
From:	Andy Lutomirski <luto@...capital.net>
To:	Brian Gerst <brgerst@...il.com>
Cc:	X86 ML <x86@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...nel.org>,
	"H. Peter Anvin" <hpa@...or.com>,
	Denys Vlasenko <dvlasenk@...hat.com>,
	Borislav Petkov <bp@...e.de>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH 3/4] x86: Rewrite switch_to() code

On Sat, May 21, 2016 at 9:04 AM, Brian Gerst <brgerst@...il.com> wrote:
> Move the low-level context switch code to an out-of-line asm stub instead of
> using complex inline asm.  This allows constructing a new stack frame for the
> child process to make it seamlessly flow to ret_from_fork without an extra
> test and branch in __switch_to().  It also improves code generation for
> __schedule() by using the C calling convention instead of clobbering all
> registers.

Just a heads up: I'm writing some code that conflicts with this patch.
The conflict will be easy to resolve, and, if this patch beats mine to
-tip, I'll rebase.

--Andy