From: Catalin Marinas <catalin.marinas@arm.com>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Konstantin Khlebnikov <k.khlebnikov@samsung.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH RFC 3/3] ARM: reduce size of page table directory for short mode
Date: Tue, 18 Nov 2014 23:02:55 +0000 [thread overview]
Message-ID: <20141118230255.GA3841@e104818-lin.cambridge.arm.com> (raw)
In-Reply-To: <20141118191104.GD4042@n2100.arm.linux.org.uk>
On Tue, Nov 18, 2014 at 07:11:04PM +0000, Russell King - ARM Linux wrote:
> On Tue, Nov 18, 2014 at 06:14:12PM +0000, Catalin Marinas wrote:
> > Actually, with LPAE you can save a pmd and pte allocated for the vectors
> > page at 0xffff0000. So you can save 8K per task here. Similarly with the
> > classic MMU, you can save another 4K for the vectors page pte.
>
> No. For any CPU which has high vectors (approximately ARMv5 and up),
> there is no "vectors page pte". The vectors page PTE is only allocated
> when we need low vectors.
You are right. The kernel pgd entries are copied by pgd_alloc, so no
need for additional pmd/pte allocations (they would be shared).
--
Catalin
prev parent reply other threads:[~2014-11-18 23:03 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-18 15:53 [PATCH RFC 1/3] ARM: LPAE: rework TTBR0/TTBR1 split Konstantin Khlebnikov
2014-11-18 15:53 ` [PATCH RFC 2/3] ARM: enable TTBR0/TTBR1 split in short mode Konstantin Khlebnikov
2014-11-18 18:04 ` Catalin Marinas
2014-11-18 15:53 ` [PATCH RFC 3/3] ARM: reduce size of page table directory for " Konstantin Khlebnikov
2014-11-18 18:14 ` Catalin Marinas
2014-11-18 19:11 ` Russell King - ARM Linux
2014-11-18 23:02 ` Catalin Marinas [this message]
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