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  1. 15 3月, 2009 7 次提交
    • J
      x86: allow extend_brk users to reserve brk space · 796216a5
      由 Jeremy Fitzhardinge 提交于 
      Impact: new interface; remove hard-coded limit

Add RESERVE_BRK(name, size) macro to reserve space in the brk
area.  This should be a conservative (ie, larger) estimate of
how much space might possibly be required from the brk area.
Any unused space will be freed, so there's no real downside
on making the reservation too large (within limits).

The name should be unique within a given file, and somewhat
descriptive.

The C definition of RESERVE_BRK() ends up being more complex than
one would expect to work around a cluster of gcc infelicities:

  The first attempt was to simply try putting __section(.brk_reservation)
  on a variable.  This doesn't work because it ends up making it a
  @progbits section, which gets actual space allocated in the vmlinux
  executable.

  The second attempt was to emit the space into a section using asm,
  but gcc doesn't allow arguments to be passed to file-level asm()
  statements, making it hard to pass in the size.

  The final attempt is to wrap the asm() in a function to allow
  it to have arguments, and put the function itself into the
  .discard section, which vmlinux*.lds drops entirely from the
  emitted vmlinux.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
      796216a5
    • Y
      x86-32: compute initial mapping size more accurately · 7543c1de
      由 Yinghai Lu 提交于 
      Impact: simplification

We only need to map the kernel in head_32.S, not the whole of
lowmem.  We use 512MB as a reasonable (but arbitrary) limit on
the maximum size of the kernel image.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
      7543c1de
    • J
      x86: use brk allocation for DMI · 6de6cb44
      由 Jeremy Fitzhardinge 提交于 
      Impact: use new interface instead of previous ad hoc implementation

Use extend_brk() to allocate memory for DMI rather than having an
ad-hoc allocator.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
      6de6cb44
    • J
      x86-32: use brk segment for allocating initial kernel pagetable · ccf3fe02
      由 Jeremy Fitzhardinge 提交于 
      Impact: use new interface instead of previous ad hoc implementation

Rather than having special purpose init_pg_table_start/end variables
to delimit the kernel pagetable built by head_32.S, just use the brk
mechanism to extend the bss for the new pagetable.

This patch removes init_pg_table_start/end and pg0, defines __brk_base
(which is page-aligned and immediately follows _end), initializes
the brk region to start there, and uses it for the 32-bit pagetable.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
      ccf3fe02
    • H
      x86: move brk initialization out of #ifdef CONFIG_BLK_DEV_INITRD · 5368a2be
      由 H. Peter Anvin 提交于 
      Impact: build fix

The brk initialization functions were incorrectly located inside
an #ifdef CONFIG_VLK_DEV_INITRD block, causing the obvious build failure in
minimal configurations.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
      5368a2be
    • J
      x86: add brk allocation for very, very early allocations · 93dbda7c
      由 Jeremy Fitzhardinge 提交于 
      Impact: new interface

Add a brk()-like allocator which effectively extends the bss in order
to allow very early code to do dynamic allocations.  This is better than
using statically allocated arrays for data in subsystems which may never
get used.

The space for brk allocations is in the bss ELF segment, so that the
space is mapped properly by the code which maps the kernel, and so
that bootloaders keep the space free rather than putting a ramdisk or
something into it.

The bss itself, delimited by __bss_stop, ends before the brk area
(__brk_base to __brk_limit).  The kernel text, data and bss is reserved
up to __bss_stop.

Any brk-allocated data is reserved separately just before the kernel
pagetable is built, as that code allocates from unreserved spaces
in the e820 map, potentially allocating from any unused brk memory.
Ultimately any unused memory in the brk area is used in the general
kernel memory pool.

Initially the brk space is set to 1MB, which is probably much larger
than any user needs (the largest current user is i386 head_32.S's code
to build the pagetables to map the kernel, which can get fairly large
with a big kernel image and no PSE support).  So long as the system
has sufficient memory for the bootloader to reserve the kernel+1MB brk,
there are no bad effects resulting from an over-large brk.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
      93dbda7c
    • J
      x86: make section delimiter symbols part of their section · b9719a4d
      由 Jeremy Fitzhardinge 提交于 
      Impact: cleanup

Move the symbols delimiting a section part of the section
(section relative) rather than absolute.  This avoids any
unexpected gaps between the section-start symbol and the first
data in the section, which could be caused by implicit
alignment of the section data.  It also makes the general
form of vmlinux_64.lds.S consistent with vmlinux_32.lds.S.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
      b9719a4d
  3. 14 3月, 2009 1 次提交
  5. 13 3月, 2009 1 次提交
    • L
      cpuacct: reduce one NULL check in fast-path · 7a46c594
      由 Li Zefan 提交于 
      Impact: micro-optimization

In cpuacct_charge(), task_ca() will never return NULL, so change
for(...) to do { } while(...) to save one NULL check.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Menage <menage@google.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
LKML-Reference: <49B863F5.2060400@cn.fujitsu.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      7a46c594
  7. 12 3月, 2009 11 次提交
  9. 11 3月, 2009 20 次提交