From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx183.postini.com [74.125.245.183]) by kanga.kvack.org (Postfix) with SMTP id 363F36B005A for ; Wed, 27 Jun 2012 01:53:26 -0400 (EDT) Message-ID: <4FEA9FDD.6030102@kernel.org> Date: Wed, 27 Jun 2012 14:53:33 +0900 From: Minchan Kim MIME-Version: 1.0 Subject: Re: [PATCH 3/3] x86: add local_tlb_flush_kernel_range() References: <1340640878-27536-1-git-send-email-sjenning@linux.vnet.ibm.com> <1340640878-27536-4-git-send-email-sjenning@linux.vnet.ibm.com> In-Reply-To: <1340640878-27536-4-git-send-email-sjenning@linux.vnet.ibm.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Seth Jennings Cc: Greg Kroah-Hartman , devel@driverdev.osuosl.org, Dan Magenheimer , Konrad Rzeszutek Wilk , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Robert Jennings , Nitin Gupta , Alex Shi On 06/26/2012 01:14 AM, Seth Jennings wrote: > This patch adds support for a local_tlb_flush_kernel_range() > function for the x86 arch. This function allows for CPU-local > TLB flushing, potentially using invlpg for single entry flushing, > using an arch independent function name. > > Signed-off-by: Seth Jennings Anyway, we don't matter INVLPG_BREAK_EVEN_PAGES's optimization point is 8 or something. We do care only it works without big problem. I believe after Alex's patch is settle down, we can fix it if it's wrong. But it shouldn't prevent merging this patch. Acked-by: Minchan Kim Nitpick: I expect you change __HAVE_LOCAL_XXX to __HAVE_ARCH_LOCAL_XXX in next spin. :) > --- > arch/x86/include/asm/tlbflush.h | 21 +++++++++++++++++++++ > 1 file changed, 21 insertions(+) > > diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h > index 36a1a2a..92a280b 100644 > --- a/arch/x86/include/asm/tlbflush.h > +++ b/arch/x86/include/asm/tlbflush.h > @@ -168,4 +168,25 @@ static inline void flush_tlb_kernel_range(unsigned long start, > flush_tlb_all(); > } > > +#define __HAVE_LOCAL_FLUSH_TLB_KERNEL_RANGE > +/* > + * INVLPG_BREAK_EVEN_PAGES is the number of pages after which single tlb > + * flushing becomes more costly than just doing a complete tlb flush. > + * While this break even point varies among x86 hardware, tests have shown > + * that 8 is a good generic value. > +*/ > +#define INVLPG_BREAK_EVEN_PAGES 8 > +static inline void local_flush_tlb_kernel_range(unsigned long start, > + unsigned long end) > +{ > + if (cpu_has_invlpg && > + (end - start)/PAGE_SIZE <= INVLPG_BREAK_EVEN_PAGES) { > + while (start < end) { > + __flush_tlb_single(start); > + start += PAGE_SIZE; > + } > + } else > + local_flush_tlb(); > +} > + > #endif /* _ASM_X86_TLBFLUSH_H */ -- Kind regards, Minchan Kim -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org