From: Dave Hansen <dave.hansen@intel.com>
To: Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>
Cc: x86@kernel.org, Peter Zijlstra <peterz@infradead.org>,
Bin Yang <bin.yang@intel.com>, Mark Gross <mark.gross@intel.com>
Subject: Re: [patch V3 11/11] x86/mm/cpa: Avoid the 4k pages check completely
Date: Fri, 21 Sep 2018 13:32:12 -0700 [thread overview]
Message-ID: <8b83d5e2-2374-1986-5fae-9e898eee1a7b@intel.com> (raw)
In-Reply-To: <20180917143546.589642503@linutronix.de>
On 09/17/2018 07:29 AM, Thomas Gleixner wrote:
> + * There used to be a 4k wise evaluation trying really hard to
> + * preserve the large pages, but experimentation has shown, that this
> + * does not help at all. There might be corner cases which would
> + * preserve one large page occasionally, but it's really not worth the
> + * extra code and cycles for the common case.
My only concern with this is that if this goes bad, it will be silently
bad and we'll just have an unnecessarily fractured direct map.
But, writing code to go verify the page tables and make sure they're
sane is a task for another day.
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
next prev parent reply other threads:[~2018-09-21 20:32 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-17 14:29 [patch V3 00/11] x86/mm/cpa: Improve large page preservation handling Thomas Gleixner
2018-09-17 14:29 ` [patch V3 01/11] x86/mm/init32: Mark text and rodata RO in one go Thomas Gleixner
2018-09-21 16:15 ` Dave Hansen
2018-09-27 18:45 ` [tip:x86/mm] " tip-bot for Thomas Gleixner
2018-09-17 14:29 ` [patch V3 02/11] x86/mm/cpa: Split, rename and clean up try_preserve_large_page() Thomas Gleixner
2018-09-18 7:03 ` Peter Zijlstra
2018-09-18 8:19 ` Peter Zijlstra
2018-09-18 12:14 ` Peter Zijlstra
2018-09-18 22:34 ` Thomas Gleixner
2018-09-21 16:22 ` Dave Hansen
2018-09-27 18:46 ` [tip:x86/mm] " tip-bot for Thomas Gleixner
2018-09-17 14:29 ` [patch V3 03/11] x86/mm/cpa: Rework static_protections() Thomas Gleixner
2018-09-21 16:33 ` Dave Hansen
2018-09-27 18:46 ` [tip:x86/mm] " tip-bot for Thomas Gleixner
2018-09-17 14:29 ` [patch V3 04/11] x86/mm/cpa: Allow range check for static protections Thomas Gleixner
2018-09-21 16:36 ` Dave Hansen
2018-09-27 18:47 ` [tip:x86/mm] " tip-bot for Thomas Gleixner
2018-09-17 14:29 ` [patch V3 05/11] x86/mm/cpa: Add debug mechanism Thomas Gleixner
2018-09-21 16:40 ` Dave Hansen
2018-09-22 10:33 ` Peter Zijlstra
2018-09-27 18:48 ` [tip:x86/mm] " tip-bot for Thomas Gleixner
2018-09-17 14:29 ` [patch V3 06/11] x86/mm/cpa: Add large page preservation statistics Thomas Gleixner
2018-09-21 19:59 ` Dave Hansen
2018-09-27 18:48 ` [tip:x86/mm] " tip-bot for Thomas Gleixner
2018-09-17 14:29 ` [patch V3 07/11] x86/mm/cpa: Avoid static protection checks on unmap Thomas Gleixner
2018-09-21 20:01 ` Dave Hansen
2018-09-27 18:49 ` [tip:x86/mm] " tip-bot for Thomas Gleixner
2018-09-17 14:29 ` [patch V3 08/11] x86/mm/cpa: Add sanity check for existing mappings Thomas Gleixner
2018-09-18 7:14 ` Peter Zijlstra
2018-09-21 20:07 ` Dave Hansen
2018-09-27 18:49 ` [tip:x86/mm] " tip-bot for Thomas Gleixner
2018-09-17 14:29 ` [patch V3 09/11] x86/mm/cpa: Optimize same protection check Thomas Gleixner
2018-09-21 20:12 ` Dave Hansen
2018-09-27 18:07 ` Thomas Gleixner
2018-09-27 18:50 ` [tip:x86/mm] " tip-bot for Thomas Gleixner
2018-09-17 14:29 ` [patch V3 10/11] x86/mm/cpa: Do the range check early Thomas Gleixner
2018-09-21 20:26 ` Dave Hansen
2018-09-27 18:50 ` [tip:x86/mm] " tip-bot for Thomas Gleixner
2018-09-17 14:29 ` [patch V3 11/11] x86/mm/cpa: Avoid the 4k pages check completely Thomas Gleixner
2018-09-21 20:32 ` Dave Hansen [this message]
2018-09-27 18:51 ` [tip:x86/mm] " tip-bot for Thomas Gleixner
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