From: Pekka Enberg <penberg@kernel.org>
To: Yinghai Lu <yinghai@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
"H. Peter Anvin" <hpa@zytor.com>, Jacob Shin <jacob.shin@amd.com>,
Tejun Heo <tj@kernel.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH -v3 14/14] x86, mm: Map ISA area with connected ram range at the same time
Date: Wed, 5 Sep 2012 11:02:33 +0300 [thread overview]
Message-ID: <CAOJsxLGXQ9+5uEvq-Pfxt=zZLWR3ZmR1WPeN=pzdzQVjHWrd0g@mail.gmail.com> (raw)
In-Reply-To: <1346823991-22911-15-git-send-email-yinghai@kernel.org>
On Wed, Sep 5, 2012 at 8:46 AM, Yinghai Lu <yinghai@kernel.org> wrote:
> so could reduce one loop.
>
> Signed-off-by: Yinghai Lu <yinghai@kernel.org>
How significant is the speed gain? The "isa_done" flag makes code flow
more difficult to follow.
> ---
> arch/x86/mm/init.c | 21 ++++++++++++++-------
> 1 files changed, 14 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
> index 6663f61..e69f832 100644
> --- a/arch/x86/mm/init.c
> +++ b/arch/x86/mm/init.c
> @@ -248,20 +248,27 @@ static void __init walk_ram_ranges(
> void *data)
> {
> unsigned long start_pfn, end_pfn;
> + bool isa_done = false;
> int i;
>
> - /* the ISA range is always mapped regardless of memory holes */
> - work_fn(0, ISA_END_ADDRESS, data);
> -
> for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) {
> u64 start = start_pfn << PAGE_SHIFT;
> u64 end = end_pfn << PAGE_SHIFT;
>
> - if (end <= ISA_END_ADDRESS)
> - continue;
> + if (!isa_done && start > ISA_END_ADDRESS) {
> + work_fn(0, ISA_END_ADDRESS, data);
> + isa_done = true;
> + } else {
> + if (end < ISA_END_ADDRESS)
> + continue;
> +
> + if (start <= ISA_END_ADDRESS &&
> + end >= ISA_END_ADDRESS) {
> + start = 0;
> + isa_done = true;
> + }
> + }
>
> - if (start < ISA_END_ADDRESS)
> - start = ISA_END_ADDRESS;
> #ifdef CONFIG_X86_32
> /* on 32 bit, we only map up to max_low_pfn */
> if ((start >> PAGE_SHIFT) >= max_low_pfn)
> --
> 1.7.7
>
> --
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next prev parent reply other threads:[~2012-09-05 8:02 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-05 5:46 [PATCH -v3 00/14] x86, mm: init_memory_mapping cleanup Yinghai Lu
2012-09-05 5:46 ` [PATCH -v3 01/14] x86, mm: Add global page_size_mask Yinghai Lu
2012-09-05 5:46 ` [PATCH -v3 02/14] x86, mm: Split out split_mem_range Yinghai Lu
2012-09-05 5:46 ` [PATCH -v3 03/14] x86, mm: Moving init_memory_mapping calling Yinghai Lu
2012-09-05 5:46 ` [PATCH -v3 04/14] x86, mm: Revert back good_end setting for 64bit Yinghai Lu
2012-09-05 5:46 ` [PATCH -v3 05/14] x86, mm: Find early page table only one time Yinghai Lu
2012-09-05 5:46 ` [PATCH -v3 06/14] x86, mm: Separate out calculate_table_space_size() Yinghai Lu
2012-09-05 5:46 ` [PATCH -v3 07/14] x86, mm: Move down two calculate_table_space_size down Yinghai Lu
2012-09-05 5:46 ` [PATCH -v3 08/14] x86, mm: set memblock initial limit to 1M Yinghai Lu
2012-09-05 5:46 ` [PATCH -v3 09/14] x86: if kernel .text .data .bss are not marked as E820_RAM, complain and fix Yinghai Lu
2012-09-05 5:46 ` [PATCH -v3 10/14] x86: Fixup code testing if a pfn is direct mapped Yinghai Lu
2012-09-05 5:46 ` [PATCH -v3 11/14] x86: Only direct map addresses that are marked as E820_RAM Yinghai Lu
2012-09-05 5:46 ` [PATCH -v3 12/14] x86/mm: calculate_table_space_size based on memory ranges that are being mapped Yinghai Lu
2012-09-05 5:46 ` [PATCH -v3 13/14] x86, mm: Use func pointer to table size calculation and mapping Yinghai Lu
2012-09-05 8:02 ` Pekka Enberg
2012-09-05 5:46 ` [PATCH -v3 14/14] x86, mm: Map ISA area with connected ram range at the same time Yinghai Lu
2012-09-05 8:02 ` Pekka Enberg [this message]
2012-09-05 18:57 ` Yinghai Lu
2012-09-06 7:22 ` Pekka Enberg
2012-09-06 14:13 ` Jacob Shin
2012-09-05 20:08 ` [PATCH -v3 00/14] x86, mm: init_memory_mapping cleanup Jacob Shin
2012-09-13 15:00 ` Jacob Shin
2012-09-27 8:22 ` Yinghai Lu
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