From: Peter Zijlstra <peterz@infradead.org>
To: Alex Shi <alex.shi@intel.com>
Cc: Nick Piggin <npiggin@gmail.com>,
tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com,
arnd@arndb.de, rostedt@goodmis.org, fweisbec@gmail.com,
jeremy@goop.org, 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,
tj@kernel.org, oleg@redhat.com, axboe@kernel.dk,
jmorris@namei.org, kamezawa.hiroyu@jp.fujitsu.com,
viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org,
yongjie.ren@intel.com, linux-arch@vger.kernel.org
Subject: Re: [PATCH v5 6/7] x86/tlb: optimizing flush_tlb_mm
Date: Wed, 16 May 2012 23:09:29 +0200 [thread overview]
Message-ID: <1337202569.4281.13.camel@twins> (raw)
In-Reply-To: <4FB3ACD2.5010900@intel.com>
On Wed, 2012-05-16 at 21:34 +0800, Alex Shi wrote:
>
> So, if the minimum change of tlb->start/end can be protected by
> HAVE_GENERIC_MMU_GATHER, it is safe and harmless, am I right?
>
safe yes, but not entirely harmless. A quick look seems to suggest you
fail for VM_HUGETLB. If your mmu_gather spans a vma with VM_HUGETLB
you'll do a regular range flush not a full mm flush like the other paths
do.
Anyway, I did a quick refresh of my series on a recent -tip tree:
git://git.kernel.org/pub/scm/linux/kernel/git/peterz/mmu.git tlb-unify
With that all you need is to "select HAVE_MMU_GATHER_RANGE" for x86 and
implement a useful flush_tlb_range().
In particular, see:
http://git.kernel.org/?p=linux/kernel/git/peterz/mmu.git;a=commitdiff;h=05e53144177e6242fda404045f50f48114bcf185;hp=2cd7dc710652127522392f4b7ecb5fa6e954941e
I've slightly changed the code to address an open issue with the
vm_flags tracking. We now force flush the mmu_gather whenever VM_HUGETLB
flips because most (all?) archs that look at that flag expect pure huge
pages and not a mixture.
I've seem to have misplaced my cross-compiler set, so I've only compiled
x86-64 for now.
next prev parent reply other threads:[~2012-05-16 21:10 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-15 8:55 [PATCH v5 0/7] tlb flush optimization for x86 Alex Shi
2012-05-15 8:55 ` [PATCH v5 1/7] x86/tlb: unify TLB_FLUSH_ALL definition Alex Shi
2012-05-15 8:55 ` [PATCH v5 2/7] x86/tlb_info: get last level TLB entry number of CPU Alex Shi
2012-05-15 8:55 ` [PATCH v5 3/7] x86/flush_tlb: try flush_tlb_single one by one in flush_tlb_range Alex Shi
2012-05-15 8:55 ` [PATCH v5 4/7] x86/tlb: fall back to flush all when meet a THP large page Alex Shi
2012-05-15 8:55 ` [PATCH v5 5/7] x86/tlb: add tlb_flushall_shift for specific CPU Alex Shi
2012-05-16 6:49 ` Alex Shi
2012-05-16 17:55 ` H. Peter Anvin
2012-05-17 1:46 ` Alex Shi
2012-05-15 8:55 ` [PATCH v5 6/7] x86/tlb: optimizing flush_tlb_mm Alex Shi
2012-05-15 9:11 ` Peter Zijlstra
2012-05-15 9:15 ` Nick Piggin
2012-05-15 9:17 ` Nick Piggin
2012-05-15 12:58 ` Luming Yu
2012-05-15 13:06 ` Peter Zijlstra
2012-05-15 13:27 ` Luming Yu
2012-05-15 13:28 ` Alex Shi
2012-05-15 13:33 ` Alex Shi
2012-05-15 13:39 ` Steven Rostedt
2012-05-15 14:04 ` Borislav Petkov
2012-05-15 13:08 ` Luming Yu
2012-05-15 14:07 ` Alex Shi
2012-05-15 9:18 ` Peter Zijlstra
2012-05-15 9:52 ` Nick Piggin
2012-05-15 10:00 ` Peter Zijlstra
2012-05-15 10:06 ` Nick Piggin
2012-05-15 10:13 ` Peter Zijlstra
2012-05-15 14:04 ` Alex Shi
2012-05-15 13:24 ` Alex Shi
2012-05-15 14:36 ` Peter Zijlstra
2012-05-15 14:57 ` Peter Zijlstra
2012-05-15 15:01 ` Alex Shi
2012-05-16 6:46 ` Alex Shi
2012-05-16 6:46 ` Alex Shi
2012-05-16 8:00 ` Peter Zijlstra
2012-05-16 8:04 ` Peter Zijlstra
2012-05-16 8:53 ` Alex Shi
2012-05-16 8:58 ` Peter Zijlstra
2012-05-16 10:58 ` Alex Shi
2012-05-16 11:04 ` Peter Zijlstra
2012-05-16 12:57 ` Alex Shi
2012-05-16 13:34 ` Alex Shi
2012-05-16 13:34 ` Alex Shi
2012-05-16 21:09 ` Peter Zijlstra [this message]
2012-05-17 0:43 ` Alex Shi
2012-05-17 2:07 ` Steven Rostedt
2012-05-17 8:04 ` Alex Shi
2012-05-17 2:14 ` Paul Mundt
2012-05-16 13:44 ` Alex Shi
2012-05-15 8:55 ` [PATCH v5 7/7] x86/tlb: add tlb_flushall_shift knob into debugfs Alex Shi
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