linux-kernel - Re: [PATCH] x86/tlb: Simplify choose_new

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Message-ID: <20250403113941.GEZ-5zfeSoAcGN1Ygo@fat_crate.local>
Date: Thu, 3 Apr 2025 13:39:41 +0200
From: Borislav Petkov <bp@...en8.de>
To: Ingo Molnar <mingo@...nel.org>
Cc: Borislav Petkov <bp@...nel.org>, X86 ML <x86@...nel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Rik van Riel <riel@...riel.com>, "H. Peter Anvin" <hpa@...or.com>
Subject: Re: [PATCH] x86/tlb: Simplify choose_new_asid()

On Thu, Apr 03, 2025 at 01:36:20PM +0200, Ingo Molnar wrote:
> Note how the cleaned up return signature not only makes the code easier 
> to read, but also helps the compiler generate better code:

Yap, and the psABI guarantees that struct is returned in a u32 reg so the asm
looks pretty good.

>   # arch/x86/mm/tlb.o:
> 
>    text	   data	    bss	    dec	    hex	filename
>    9341	    753	    516	  10610	   2972	tlb.o.before
>    9213	    753	    516	  10482	   28f2	tlb.o.after
> 
> Personally I also like the non-bool new_asid::need_flush easier to read 
> in this 'HW interface' context.

Thx.

-- 
Regards/Gruss,
    Boris.

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