From: Mikael Pettersson <mikpe@csd.uu.se>
To: Jens Axboe <axboe@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>, Byron Stanoszek <gandalf@winds.org>,
linux-kernel@vger.kernel.org, Andrew Morton <akpm@osdl.org>,
Linus Torvalds <torvalds@osdl.org>
Subject: Re: [PATCH] Address space split configuration
Date: Tue, 10 Jan 2006 16:24:20 +0100 [thread overview]
Message-ID: <17347.53668.266546.344752@alkaid.it.uu.se> (raw)
In-Reply-To: <20060110150331.GN3389@suse.de>
Jens Axboe writes:
> Thanks! Updated patch below.
>
> ---
>
> Add option for configuring the page offset, to better optimize the
> kernel for higher memory machines. Enables users to get rid of high
> memory for eg a 1GiB machine.
>
> Signed-off-by: Jens Axboe <axboe@suse.de>
> Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Mikael Pettersson <mikpe@csd.uu.se>
> diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
> index d849c68..20d1423 100644
> --- a/arch/i386/Kconfig
> +++ b/arch/i386/Kconfig
> @@ -444,6 +464,35 @@ config HIGHMEM64G
>
> endchoice
>
> +choice
> + depends on NOHIGHMEM && EXPERIMENTAL
> + prompt "Memory split"
> + default DEFAULT_3G
> + help
> + Select the wanted split between kernel and user memory.
> +
> + If the address range available to the kernel is less than the
> + physical memory installed, the remaining memory will be available
> + as "high memory". Accessing high memory is a little more costly
> + than low memory, as it needs to be mapped into the kernel first.
> + Note that increasing the kernel address space limits the range
> + available to user programs, making the address space there
> + tighter.
> +
> + If you are not absolutely sure what you are doing, leave this
> + option alone!
> +
> + config DEFAULT_3G
> + bool "3G/1G user/kernel split"
> + config DEFAULT_3G_OPT
> + bool "3G/1G user/kernel split (for full 1G low memory)"
> + config DEFAULT_2G
> + bool "2G/2G user/kernel split"
> + config DEFAULT_1G
> + bool "1G/3G user/kernel split"
> +
> +endchoice
> +
> config HIGHMEM
> bool
> depends on HIGHMEM64G || HIGHMEM4G
> diff --git a/arch/i386/mm/init.c b/arch/i386/mm/init.c
> index 7df494b..67f1da0 100644
> --- a/arch/i386/mm/init.c
> +++ b/arch/i386/mm/init.c
> @@ -597,6 +597,12 @@ void __init mem_init(void)
> high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
> #endif
>
> +#if !defined(CONFIG_DEFAULT_3G)
> + /* if the user has less than 960MB of RAM, he should use the default */
> + if (max_low_pfn < (960 * 1024 * 1024 / PAGE_SIZE))
> + printk(KERN_INFO "Memory: less than 960MiB of RAM, you should use the default memory split setting\n");
> +#endif
> +
> /* this will put all low memory onto the freelists */
> totalram_pages += free_all_bootmem();
>
> diff --git a/include/asm-i386/page.h b/include/asm-i386/page.h
> index 73296d9..7da50a1 100644
> --- a/include/asm-i386/page.h
> +++ b/include/asm-i386/page.h
> @@ -109,11 +109,23 @@ extern int page_is_ram(unsigned long pag
>
> #endif /* __ASSEMBLY__ */
>
> +#if defined(CONFIG_DEFAULT_3G)
> +#define __PAGE_OFFSET_RAW (0xC0000000)
> +#elif defined(CONFIG_DEFAULT_3G_OPT)
> +#define __PAGE_OFFSET_RAW (0xB0000000)
> +#elif defined(CONFIG_DEFAULT_2G)
> +#define __PAGE_OFFSET_RAW (0x78000000)
> +#elif defined(CONFIG_DEFAULT_1G)
> +#define __PAGE_OFFSET_RAW (0x40000000)
> +#else
> +#error "Bad user/kernel offset"
> +#endif
> +
> #ifdef __ASSEMBLY__
> -#define __PAGE_OFFSET (0xC0000000)
> +#define __PAGE_OFFSET __PAGE_OFFSET_RAW
> #define __PHYSICAL_START CONFIG_PHYSICAL_START
> #else
> -#define __PAGE_OFFSET (0xC0000000UL)
> +#define __PAGE_OFFSET ((unsigned long)__PAGE_OFFSET_RAW)
> #define __PHYSICAL_START ((unsigned long)CONFIG_PHYSICAL_START)
> #endif
> #define __KERNEL_START (__PAGE_OFFSET + __PHYSICAL_START)
>
> --
> Jens Axboe
>
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>
next prev parent reply other threads:[~2006-01-10 15:25 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-01-10 12:58 2G memory split Jens Axboe
2006-01-10 13:29 ` Ingo Molnar
2006-01-10 13:37 ` Jens Axboe
2006-01-10 13:43 ` Byron Stanoszek
2006-01-10 13:47 ` Jens Axboe
2006-01-10 14:39 ` Jens Axboe
2006-01-10 14:44 ` Ingo Molnar
2006-01-10 15:03 ` [PATCH] Address space split configuration Jens Axboe
2006-01-10 15:11 ` Mark Lord
2006-01-10 15:24 ` Mikael Pettersson [this message]
2006-01-10 16:14 ` 2G memory split Linus Torvalds
2006-01-10 16:40 ` Mark Lord
2006-01-10 16:52 ` Linus Torvalds
2006-01-10 18:33 ` Coywolf Qi Hunt
2006-01-10 17:07 ` Mark Lord
2006-01-10 17:28 ` Linus Torvalds
2006-01-10 17:32 ` Jens Axboe
2006-01-10 17:37 ` Mark Lord
2006-01-10 18:58 ` Mark Lord
2006-01-10 19:16 ` [PATCH ] VMSPLIT config options (with default config fixed) Mark Lord
2006-01-10 17:37 ` Jeff V. Merkey
2006-01-10 19:27 ` Jens Axboe
2006-01-11 1:13 ` J.A. Magallon
2006-01-11 10:15 ` Jens Axboe
2006-01-11 16:00 ` Greg Norris
2006-01-11 17:13 ` Mark Lord
2006-01-11 17:44 ` Greg Norris
2006-02-05 18:42 ` Barry K. Nathan
2006-02-01 22:23 ` Herbert Poetzl
2006-02-02 11:04 ` Ulrich Mueller
2006-02-02 20:55 ` Jan Engelhardt
2006-02-03 22:39 ` Mark Lord
2006-02-04 10:23 ` Ulrich Mueller
2006-02-04 11:06 ` Jan Engelhardt
2006-02-04 10:36 ` Jens Axboe
2006-02-04 11:05 ` Jan Engelhardt
2006-02-04 13:57 ` Mark Lord
2006-02-05 15:32 ` J.A. Magallon
2006-02-05 15:38 ` Arjan van de Ven
2006-02-05 21:14 ` Jan Engelhardt
2006-02-05 21:19 ` Arjan van de Ven
2006-02-06 14:56 ` Jan Engelhardt
2006-02-07 0:41 ` Herbert Poetzl
2006-02-07 2:51 ` Mark Rustad
2006-02-07 9:38 ` Bernd Petrovitsch
2006-02-07 12:19 ` RFC: add an ADVANCED_USER option Adrian Bunk
2006-02-07 14:05 ` Ulrich Mueller
2006-02-07 14:42 ` Adrian Bunk
2006-02-09 16:06 ` Jan Engelhardt
2006-01-10 17:48 ` 2G memory split Bernd Eckenfels
2006-01-10 16:30 ` [PATCH] " Jeff V. Merkey
2006-01-10 18:50 ` Lennart Sorensen
2006-01-10 17:13 ` Jeff V. Merkey
2006-01-10 19:42 ` Jens Axboe
2006-01-10 20:17 ` Bernd Eckenfels
2006-01-10 20:28 ` Jens Axboe
2006-01-11 8:39 ` Bernd Eckenfels
2006-01-11 10:06 ` Jens Axboe
2006-01-10 18:14 ` Martin Bligh
2006-01-10 18:34 ` Linus Torvalds
2006-01-10 16:56 ` Jeff V. Merkey
2006-01-10 17:01 ` Jeff V. Merkey
2006-01-10 18:45 ` Mark Lord
2006-01-10 18:46 ` Martin Bligh
2006-01-10 18:58 ` Jens Axboe
2006-01-10 17:17 ` Jeff V. Merkey
2006-01-10 20:55 ` Alan Cox
2006-01-10 19:12 ` Jeff V. Merkey
2006-01-10 21:02 ` Jens Axboe
2006-01-10 19:30 ` Jeff V. Merkey
2006-01-10 18:39 ` Martin Bligh
2006-01-10 18:55 ` Dave Hansen
2006-01-10 19:01 ` Mark Lord
2006-01-10 19:05 ` Dave Hansen
2006-01-10 17:07 ` Sergey Vlasov
2006-04-10 14:11 ` Kirill Korotaev
2006-04-10 14:39 ` Mark Lord
2006-01-10 18:28 ` Coywolf Qi Hunt
2006-01-10 13:47 ` Mikael Pettersson
2006-01-10 13:54 ` Jens Axboe
2006-01-10 14:09 ` Gerd Hoffmann
2006-01-10 14:21 ` Jens Axboe
2006-01-10 14:25 ` Jens Axboe
2006-01-10 20:42 ` Jan Engelhardt
2006-01-11 0:25 ` Con Kolivas
2006-01-10 14:12 ` Mark Lord
2006-01-10 14:22 ` Jens Axboe
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