From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Jan Beulich <JBeulich@suse.com>,
xen-devel <xen-devel@lists.xenproject.org>
Cc: Keir Fraser <keir@xen.org>
Subject: Re: [PATCH v2] x86: avoid flush IPI when possible
Date: Wed, 17 Feb 2016 14:48:41 +0000 [thread overview]
Message-ID: <56C48849.4000801@citrix.com> (raw)
In-Reply-To: <56C304A502000078000D2879@prv-mh.provo.novell.com>
On 16/02/16 10:14, Jan Beulich wrote:
> --- a/xen/arch/x86/smp.c
> +++ b/xen/arch/x86/smp.c
> @@ -205,26 +205,30 @@ static unsigned int flush_flags;
>
> void invalidate_interrupt(struct cpu_user_regs *regs)
> {
> + unsigned int flags = flush_flags;
> ack_APIC_irq();
> perfc_incr(ipis);
> - if ( !__sync_local_execstate() ||
> - (flush_flags & (FLUSH_TLB_GLOBAL | FLUSH_CACHE)) )
> - flush_area_local(flush_va, flush_flags);
> + if ( __sync_local_execstate() )
> + flags &= ~FLUSH_TLB;
If a switch happened, write_ptbase() also flushed global mappings. I
believe you can also mask out FLUSH_TLB_GLOBAL here.
Otherwise, the rest looks ok. Reviewed-by: Andrew Cooper
<andrew.cooper3@citrix.com>
next prev parent reply other threads:[~2016-02-17 14:48 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-16 10:14 [PATCH v2] x86: avoid flush IPI when possible Jan Beulich
2016-02-17 14:48 ` Andrew Cooper [this message]
2016-02-18 8:44 ` Jan Beulich
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