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From: "H. Peter Anvin" <hpa@zytor.com>
To: Alex Shi <alex.shi@intel.com>
Cc: mgorman@suse.de, npiggin@gmail.com, tglx@linutronix.de,
	mingo@redhat.com, arnd@arndb.de, rostedt@goodmis.org,
	fweisbec@gmail.com, jeremy@goop.org, gregkh@linuxfoundation.org,
	glommer@redhat.com, riel@redhat.com, luto@mit.edu,
	avi@redhat.com, len.brown@intel.com, dhowells@redhat.com,
	fenghua.yu@intel.com, borislav.petkov@amd.com,
	yinghai@kernel.org, ak@linux.intel.com, cpw@sgi.com,
	steiner@sgi.com, akpm@linux-foundation.org, penberg@kernel.org,
	hughd@google.com, rientjes@google.com,
	kosaki.motohiro@jp.fujitsu.com, n-horiguchi@ah.jp.nec.com,
	paul.gortmaker@windriver.com, trenn@suse.de, tj@kernel.org,
	oleg@redhat.com, axboe@kernel.dk, a.p.zijlstra@chello.nl,
	kamezawa.hiroyu@jp.fujitsu.com, viro@zeniv.linux.org.uk,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 4/7] x86/tlb: add tlb flush all factor for specific CPUs
Date: Tue, 08 May 2012 08:18:30 -0700	[thread overview]
Message-ID: <4FA93946.2000302@zytor.com> (raw)
In-Reply-To: <1336485790-30902-5-git-send-email-alex.shi@intel.com>

On 05/08/2012 07:03 AM, Alex Shi wrote:
>  
> -	if (!cpu_has_invlpg || vma->vm_flags & VM_HUGETLB) {
> +	if (!cpu_has_invlpg || vma->vm_flags & VM_HUGETLB
> +				|| !tlb_flushall_factor) {

OK nevermind on the division by zero, but this yet another test being
performed.

If nothing else you could fold these tests and make tlb_flushall_factor
zero if !cpu_has_invlpg.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.


  parent reply	other threads:[~2012-05-08 15:19 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-08 14:03 [PATCH v3] TLB flush optimization Alex Shi
2012-05-08 14:03 ` [PATCH v3 1/7] x86/tlb_info: get last level TLB entry number of CPU Alex Shi
2012-05-08 14:03 ` [PATCH v3 2/7] x86/flush_tlb: try flush_tlb_single one by one in flush_tlb_range Alex Shi
2012-05-08 14:03 ` [PATCH v3 3/7] x86/tlb: fall back to flush all when meet a THP large page Alex Shi
2012-05-08 14:03 ` [PATCH v3 4/7] x86/tlb: add tlb flush all factor for specific CPUs Alex Shi
2012-05-08 15:08   ` Peter Zijlstra
2012-05-09  2:03     ` Alex Shi
2012-05-08 15:12   ` H. Peter Anvin
2012-05-09  2:10     ` Alex Shi
2012-05-08 15:15   ` H. Peter Anvin
2012-05-08 15:56     ` Andi Kleen
2012-05-08 16:40       ` H. Peter Anvin
2012-05-08 15:18   ` H. Peter Anvin [this message]
2012-05-09  1:41     ` Alex Shi
2012-05-08 14:03 ` [PATCH v3 5/7] x86/tlb: remove comments for tlb_flush_range implement suggestion Alex Shi
2012-05-09  8:22   ` Nick Piggin
2012-05-08 14:03 ` [PATCH v3 6/7] x86/tlb: optimizing flush_tlb_mm Alex Shi
2012-05-08 15:09   ` Peter Zijlstra
2012-05-08 14:03 ` [PATCH v3 7/7] x86/tlb: add tlb_flushall_factor into sysfs for user change Alex Shi
2012-05-08 15:11   ` Peter Zijlstra
2012-05-08 15:20     ` H. Peter Anvin
2012-05-08 15:25       ` Borislav Petkov
2012-05-08 15:31         ` H. Peter Anvin
2012-05-08 15:41           ` Borislav Petkov
2012-05-08 15:48             ` H. Peter Anvin
2012-05-08 16:10               ` Greg KH
2012-05-08 16:28                 ` Borislav Petkov
2012-05-09  5:03               ` Alex Shi
2012-05-08 15:01 ` [PATCH v3] TLB flush optimization Peter Zijlstra
2012-05-09  1:58   ` Alex Shi
2012-05-09 23:45   ` Andi Kleen
2012-05-10  5:06     ` Alex Shi
2012-05-10  7:49     ` HATAYAMA Daisuke

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