linux-kernel - Re: [RFC 09/10] x86/mm: Rework lazy TLB to track the actual loaded mm

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Message-ID: <alpine.DEB.2.20.1705092236290.2295@nanos>
Date:   Tue, 9 May 2017 22:41:27 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Andy Lutomirski <luto@...nel.org>
cc:     X86 ML <x86@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Borislav Petkov <bpetkov@...e.de>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Mel Gorman <mgorman@...e.de>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        Rik van Riel <riel@...hat.com>,
        Dave Hansen <dave.hansen@...el.com>,
        Nadav Amit <namit@...are.com>, Michal Hocko <mhocko@...e.com>,
        Arjan van de Ven <arjan@...ux.intel.com>
Subject: Re: [RFC 09/10] x86/mm: Rework lazy TLB to track the actual loaded
 mm

On Sun, 7 May 2017, Andy Lutomirski wrote:
>  /* context.lock is held for us, so we don't need any locking. */
>  static void flush_ldt(void *current_mm)
>  {
> +	struct mm_struct *mm = current_mm;
>  	mm_context_t *pc;
>  
> -	if (current->active_mm != current_mm)
> +	if (this_cpu_read(cpu_tlbstate.loaded_mm) != current_mm)

While functional correct, this really should compare against 'mm'.

>  		return;
>  
> -	pc = &current->active_mm->context;
> +	pc = &mm->context;

Thanks,

	tglx