* Jeremy Fitzhardinge ([EMAIL PROTECTED]) wrote:
> Subject: i386: map enough initial memory to create lowmem mappings
>
> head.S creates the very initial pagetable for the kernel. This just
> maps enough space for the kernel itself, and an allocation bitmap.
> The amount of mapped memory is
Jeremy Fitzhardinge wrote:
H. Peter Anvin wrote:
Even with PSE?
Perhaps not.
However, the main reason I wanted it done that way is to avoid cargo
cult programming; this makes it much clearer where the numbers
actually come from.
Well, how about this then?
I like.
Acked-by: H. Peter
H. Peter Anvin wrote:
#ifdef CONFIG_X86_PAE
PAGE_TABLE_SIZE = (2048+4)*4096
#else
PAGE_TABLE_SIZE = (1024+1)*4096
#endif
BOOTMEM_SIZE = 128*1024
/* ACPI and SMP trampoline allocate bootmem pages before paging_init */
#ifdef CONFIG_SMP
SMP_BOOTMEM_EARLY= 1
#else
SMP_BOOTMEM_EARLY= 0
#endif
H. Peter Anvin wrote:
> Even with PSE?
Perhaps not.
> However, the main reason I wanted it done that way is to avoid cargo
> cult programming; this makes it much clearer where the numbers
> actually come from.
Well, how about this then?
Subject: i386: map enough initial memory to create lowmem
Jeremy Fitzhardinge wrote:
H. Peter Anvin wrote:
I suggest, for clarity and to minimize bloat:
I think it would save a page, at most. But OK. (Also, if you're
running !PAE, these pages will actually become part of the init_mm
pagetable, so there's no memory wastage at all.)
Even with PSE?
H. Peter Anvin wrote:
Jeremy Fitzhardinge wrote:
H. Peter Anvin wrote:
Really (pae ? 2M : 1M), in other words, plus the 128K for bootmem.
Note that this is creating page tables for, not erasing. To map 2M,
we will only use 2K of additional memory (meaning there is 50% chance
we end up using
H. Peter Anvin wrote:
> I suggest, for clarity and to minimize bloat:
I think it would save a page, at most. But OK. (Also, if you're
running !PAE, these pages will actually become part of the init_mm
pagetable, so there's no memory wastage at all.)
> #ifdef CONFIG_X86_PAE
> # define
Jeremy Fitzhardinge wrote:
H. Peter Anvin wrote:
Really (pae ? 2M : 1M), in other words, plus the 128K for bootmem.
Note that this is creating page tables for, not erasing. To map 2M,
we will only use 2K of additional memory (meaning there is 50% chance
we end up using an additional 4K page.)
H. Peter Anvin wrote:
> Really (pae ? 2M : 1M), in other words, plus the 128K for bootmem.
> Note that this is creating page tables for, not erasing. To map 2M,
> we will only use 2K of additional memory (meaning there is 50% chance
> we end up using an additional 4K page.)
>
> So the solution
Zachary Amsden wrote:
Jeremy Fitzhardinge wrote:
It seems to me that the problem is simply that it runs out of space.
head.S maps 8Mbytes of memory.
8 MB was a long time ago.
head.S maps the kernel size plus INIT_MAP_BEYOND_END, which is currently
set to 128K.
The kernel takes ~6.8M of
Zachary Amsden wrote:
> Note you can always run out of space; to ensure safety, the init code
> needs to not use a fixed mapping size, it needs to map
> end_kernel_address + pae ? 1808k : 896k, assuming 128M vmalloc hole.
> This could cause problems like running into initrd, however, so might
>
Jeremy Fitzhardinge wrote:
It seems to me that the problem is simply that it runs out of space.
head.S maps 8Mbytes of memory. The kernel takes ~6.8M of that, and
there simply isn't enough remaining space to fit the pagetables to map
all memory into the kernel address space. Here's my dump of
Jeremy Fitzhardinge wrote:
It seems to me that the problem is simply that it runs out of space.
head.S maps 8Mbytes of memory. The kernel takes ~6.8M of that, and
there simply isn't enough remaining space to fit the pagetables to map
all memory into the kernel address space. Here's my dump of
Zachary Amsden wrote:
Note you can always run out of space; to ensure safety, the init code
needs to not use a fixed mapping size, it needs to map
end_kernel_address + pae ? 1808k : 896k, assuming 128M vmalloc hole.
This could cause problems like running into initrd, however, so might
Zachary Amsden wrote:
Jeremy Fitzhardinge wrote:
It seems to me that the problem is simply that it runs out of space.
head.S maps 8Mbytes of memory.
8 MB was a long time ago.
head.S maps the kernel size plus INIT_MAP_BEYOND_END, which is currently
set to 128K.
The kernel takes ~6.8M of
H. Peter Anvin wrote:
Really (pae ? 2M : 1M), in other words, plus the 128K for bootmem.
Note that this is creating page tables for, not erasing. To map 2M,
we will only use 2K of additional memory (meaning there is 50% chance
we end up using an additional 4K page.)
So the solution is
Jeremy Fitzhardinge wrote:
H. Peter Anvin wrote:
Really (pae ? 2M : 1M), in other words, plus the 128K for bootmem.
Note that this is creating page tables for, not erasing. To map 2M,
we will only use 2K of additional memory (meaning there is 50% chance
we end up using an additional 4K page.)
H. Peter Anvin wrote:
I suggest, for clarity and to minimize bloat:
I think it would save a page, at most. But OK. (Also, if you're
running !PAE, these pages will actually become part of the init_mm
pagetable, so there's no memory wastage at all.)
#ifdef CONFIG_X86_PAE
# define
H. Peter Anvin wrote:
Jeremy Fitzhardinge wrote:
H. Peter Anvin wrote:
Really (pae ? 2M : 1M), in other words, plus the 128K for bootmem.
Note that this is creating page tables for, not erasing. To map 2M,
we will only use 2K of additional memory (meaning there is 50% chance
we end up using
Jeremy Fitzhardinge wrote:
H. Peter Anvin wrote:
I suggest, for clarity and to minimize bloat:
I think it would save a page, at most. But OK. (Also, if you're
running !PAE, these pages will actually become part of the init_mm
pagetable, so there's no memory wastage at all.)
Even with PSE?
H. Peter Anvin wrote:
Even with PSE?
Perhaps not.
However, the main reason I wanted it done that way is to avoid cargo
cult programming; this makes it much clearer where the numbers
actually come from.
Well, how about this then?
Subject: i386: map enough initial memory to create lowmem
H. Peter Anvin wrote:
#ifdef CONFIG_X86_PAE
PAGE_TABLE_SIZE = (2048+4)*4096
#else
PAGE_TABLE_SIZE = (1024+1)*4096
#endif
BOOTMEM_SIZE = 128*1024
/* ACPI and SMP trampoline allocate bootmem pages before paging_init */
#ifdef CONFIG_SMP
SMP_BOOTMEM_EARLY= 1
#else
SMP_BOOTMEM_EARLY= 0
#endif
Jeremy Fitzhardinge wrote:
H. Peter Anvin wrote:
Even with PSE?
Perhaps not.
However, the main reason I wanted it done that way is to avoid cargo
cult programming; this makes it much clearer where the numbers
actually come from.
Well, how about this then?
I like.
Acked-by: H. Peter
* Jeremy Fitzhardinge ([EMAIL PROTECTED]) wrote:
Subject: i386: map enough initial memory to create lowmem mappings
head.S creates the very initial pagetable for the kernel. This just
maps enough space for the kernel itself, and an allocation bitmap.
The amount of mapped memory is rounded
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