From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/2] ARM: LPAE: reduce damage caused by idmap to virtual memory layout
Date: Mon, 28 Jul 2014 19:14:56 +0100 [thread overview]
Message-ID: <20140728181456.GO15536@arm.com> (raw)
In-Reply-To: <20140722153635.25088.14197.stgit@buzz>
On Tue, Jul 22, 2014 at 04:36:35PM +0100, Konstantin Khlebnikov wrote:
> idmap layout combines both phisical and virtual addresses.
> Everything works fine if ram physically lays below PAGE_OFFSET.
> Otherwise idmap starts punching huge holes in virtual memory layout.
> It maps ram by 2MiB sections, but when it allocates new pmd page it
> cuts 1GiB at once.
>
> This patch makes a copy of all affected pmds from init_mm.
> Only few (usually one) 2MiB sections will be lost.
> This is not eliminates problem but makes it 512 times less likely.
I'm struggling to understand your commit message, but making a problem `512
times less likely' does sound like a bit of a hack to me. Can't we fix this
properly instead?
Will
WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will.deacon@arm.com>
To: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
Cc: Russell King <linux@arm.linux.org.uk>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Vitaly Andrianov <vitalya@ti.com>,
Cyril Chemparathy <cyril@ti.com>
Subject: Re: [PATCH 2/2] ARM: LPAE: reduce damage caused by idmap to virtual memory layout
Date: Mon, 28 Jul 2014 19:14:56 +0100 [thread overview]
Message-ID: <20140728181456.GO15536@arm.com> (raw)
In-Reply-To: <20140722153635.25088.14197.stgit@buzz>
On Tue, Jul 22, 2014 at 04:36:35PM +0100, Konstantin Khlebnikov wrote:
> idmap layout combines both phisical and virtual addresses.
> Everything works fine if ram physically lays below PAGE_OFFSET.
> Otherwise idmap starts punching huge holes in virtual memory layout.
> It maps ram by 2MiB sections, but when it allocates new pmd page it
> cuts 1GiB at once.
>
> This patch makes a copy of all affected pmds from init_mm.
> Only few (usually one) 2MiB sections will be lost.
> This is not eliminates problem but makes it 512 times less likely.
I'm struggling to understand your commit message, but making a problem `512
times less likely' does sound like a bit of a hack to me. Can't we fix this
properly instead?
Will
next prev parent reply other threads:[~2014-07-28 18:14 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-22 15:36 [PATCH 1/2] ARM: LPAE: load upper bits of early TTBR0/TTBR1 Konstantin Khlebnikov
2014-07-22 15:36 ` Konstantin Khlebnikov
2014-07-22 15:36 ` [PATCH 2/2] ARM: LPAE: reduce damage caused by idmap to virtual memory layout Konstantin Khlebnikov
2014-07-22 15:36 ` Konstantin Khlebnikov
2014-07-28 18:14 ` Will Deacon [this message]
2014-07-28 18:14 ` Will Deacon
2014-07-28 18:25 ` Konstantin Khlebnikov
2014-07-28 18:25 ` Konstantin Khlebnikov
2014-07-28 18:41 ` Will Deacon
2014-07-28 18:41 ` Will Deacon
2014-07-28 18:57 ` Konstantin Khlebnikov
2014-07-28 18:57 ` Konstantin Khlebnikov
2014-07-28 19:06 ` Will Deacon
2014-07-28 19:06 ` Will Deacon
2014-07-28 19:13 ` Russell King - ARM Linux
2014-07-28 19:13 ` Russell King - ARM Linux
2014-07-28 19:29 ` Konstantin Khlebnikov
2014-07-28 19:29 ` Konstantin Khlebnikov
2014-07-28 19:34 ` Konstantin Khlebnikov
2014-07-28 19:34 ` Konstantin Khlebnikov
2014-07-28 19:42 ` Russell King - ARM Linux
2014-07-28 19:42 ` Russell King - ARM Linux
2014-07-28 19:57 ` Konstantin Khlebnikov
2014-07-28 19:57 ` Konstantin Khlebnikov
2014-07-29 10:57 ` Russell King - ARM Linux
2014-07-29 10:57 ` Russell King - ARM Linux
2014-07-29 12:37 ` Konstantin Khlebnikov
2014-07-29 12:37 ` Konstantin Khlebnikov
2014-07-28 18:12 ` [PATCH 1/2] ARM: LPAE: load upper bits of early TTBR0/TTBR1 Will Deacon
2014-07-28 18:12 ` Will Deacon
2014-07-28 18:40 ` Konstantin Khlebnikov
2014-07-28 18:40 ` Konstantin Khlebnikov
2014-07-28 18:47 ` Will Deacon
2014-07-28 18:47 ` Will Deacon
2014-07-29 11:15 ` Will Deacon
2014-07-29 11:15 ` Will Deacon
2014-07-29 12:29 ` Konstantin Khlebnikov
2014-07-29 12:29 ` Konstantin Khlebnikov
2014-08-27 15:26 ` Jassi Brar
2014-08-27 15:26 ` Jassi Brar
2014-08-27 15:31 ` Konstantin Khlebnikov
2014-08-27 15:31 ` Konstantin Khlebnikov
2014-08-27 15:33 ` Konstantin Khlebnikov
2014-08-27 15:33 ` Konstantin Khlebnikov
2014-08-27 15:45 ` Jassi Brar
2014-08-27 15:45 ` Jassi Brar
2014-08-28 11:03 ` Will Deacon
2014-08-28 11:03 ` Will Deacon
2014-08-28 11:50 ` Konstantin Khlebnikov
2014-08-28 11:50 ` Konstantin Khlebnikov
2014-08-05 15:42 ` Konstantin Khlebnikov
2014-08-05 15:42 ` Konstantin Khlebnikov
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