09 Mar, 2011
1 commit
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Put x86 entry code into a separate link section: .entry.text.
Separating the entry text section seems to have performance
benefits - caused by more efficient instruction cache usage.Running hackbench with perf stat --repeat showed that the change
compresses the icache footprint. The icache load miss rate went
down by about 15%:before patch:
19417627 L1-icache-load-misses ( +- 0.147% )after patch:
16490788 L1-icache-load-misses ( +- 0.180% )The motivation of the patch was to fix a particular kprobes
bug that relates to the entry text section, the performance
advantage was discovered accidentally.Whole perf output follows:
- results for current tip tree:
Performance counter stats for './hackbench/hackbench 10' (500 runs):
19417627 L1-icache-load-misses ( +- 0.147% )
2676914223 instructions # 0.497 IPC ( +- 0.079% )
5389516026 cycles ( +- 0.144% )0.206267711 seconds time elapsed ( +- 0.138% )
- results for current tip tree with the patch applied:
Performance counter stats for './hackbench/hackbench 10' (500 runs):
16490788 L1-icache-load-misses ( +- 0.180% )
2717734941 instructions # 0.502 IPC ( +- 0.079% )
5414756975 cycles ( +- 0.148% )0.206747566 seconds time elapsed ( +- 0.137% )
Signed-off-by: Jiri Olsa
Cc: Arnaldo Carvalho de Melo
Cc: Frederic Weisbecker
Cc: Peter Zijlstra
Cc: Linus Torvalds
Cc: Andrew Morton
Cc: Nick Piggin
Cc: Eric Dumazet
Cc: masami.hiramatsu.pt@hitachi.com
Cc: ananth@in.ibm.com
Cc: davem@davemloft.net
Cc: 2nddept-manager@sdl.hitachi.co.jp
LKML-Reference:
Signed-off-by: Ingo Molnar
23 Sep, 2009
1 commit
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Some ports (like the Blackfin arch) have a discontiguous memory map which
means there may be text or data that falls outside of the standard range
of the start/end text/data symbols. Creating some helper functions allows
these non-standard ports to declare these regions without adversely
affecting anyone else.Signed-off-by: Mike Frysinger
Cc: Ingo Molnar
Cc: Robin Getz
Cc: Sam Ravnborg
Cc: Peter Zijlstra
Cc: Arnd Bergmann
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
19 Jun, 2009
1 commit
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Call constructors (gcc-generated initcall-like functions) during kernel
start and module load. Constructors are e.g. used for gcov data
initialization.Disable constructor support for usermode Linux to prevent conflicts with
host glibc.Signed-off-by: Peter Oberparleiter
Acked-by: Rusty Russell
Acked-by: WANG Cong
Cc: Sam Ravnborg
Cc: Jeff Dike
Cc: Andi Kleen
Cc: Huang Ying
Cc: Li Wei
Cc: Michael Ellerman
Cc: Ingo Molnar
Cc: Heiko Carstens
Cc: Martin Schwidefsky
Cc: Al Viro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
16 Jan, 2009
1 commit
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[ Based on original patch from Christoph Lameter and Mike Travis. ]
This patch makes percpu symbols zerobased on x86_64 SMP by adding
PERCPU_VADDR() to vmlinux.lds.h which helps setting explicit vaddr on
the percpu output section and using it in vmlinux_64.lds.S. A new
PHDR is added as existing ones cannot contain sections near address
zero. PERCPU_VADDR() also adds a new symbol __per_cpu_load which
always points to the vaddr of the loaded percpu data.init region.The following adjustments have been made to accomodate the address
change.* code to locate percpu gdt_page in head_64.S is updated to add the
load address to the gdt_page offset.* __per_cpu_load is used in places where access to the init data area
is necessary.* pda->data_offset is initialized soon after C code is entered as zero
value doesn't work anymore.This patch is mostly taken from Mike Travis' "x86_64: Base percpu
variables at zero" patch.Signed-off-by: Tejun Heo
Signed-off-by: Ingo Molnar
10 Sep, 2008
1 commit
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It was introduced by "vsprintf: add support for '%pS' and '%pF' pointer
formats" in commit 0fe1ef24f7bd0020f29ffe287dfdb9ead33ca0b2. However,
the current way its coded doesn't work on parisc64. For two reasons: 1)
parisc isn't in the #ifdef and 2) parisc has a different format for
function descriptorsMake dereference_function_descriptor() more accommodating by allowing
architecture overrides. I put the three overrides (for parisc64, ppc64
and ia64) in arch/kernel/module.c because that's where the kernel
internal linker which knows how to deal with function descriptors sits.Signed-off-by: James Bottomley
Acked-by: Benjamin Herrenschmidt
Acked-by: Tony Luck
Acked-by: Kyle McMartin
Signed-off-by: Linus Torvalds
07 Feb, 2008
1 commit
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When passing a zero address to kallsyms_lookup(), the kernel thought it was
a valid kernel address, even if it is not. This is because is_ksym_addr()
called is_kernel_extratext() and checked against labels that don't exist on
many archs (which default as zero). Since PPC was the only kernel which
defines _extra_text, (in 2005), and no longer needs it, this patch removes
_extra_text support.For some history (provided by Jon):
http://ozlabs.org/pipermail/linuxppc-dev/2005-September/019734.html
http://ozlabs.org/pipermail/linuxppc-dev/2005-September/019736.html
http://ozlabs.org/pipermail/linuxppc-dev/2005-September/019751.html[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Robin Getz
Cc: David Woodhouse
Cc: Jon Loeliger
Cc: Paul Mackerras
Cc: Benjamin Herrenschmidt
Cc: Sam Ravnborg
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
02 Jul, 2006
1 commit
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Add __start_rodata and __end_rodata to sections.h to avoid extern
declarations. Needed by s390 code (see following patch).[akpm@osdl.org: update architectures]
Cc: Arjan van de Ven
Cc: Martin Schwidefsky
Signed-off-by: Heiko Carstens
Cc: Andi Kleen
Acked-by: Kyle McMartin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
15 Nov, 2005
1 commit
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Adding __initdata_* to asm-generic/sections.h
Replaces a lot of open coded externs in arch/x86_64/*
I had to change __bss_end to __bss_stop to match the other architectures.Signed-off-by: Andi Kleen
Signed-off-by: Linus Torvalds
08 Sep, 2005
1 commit
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There are possible race conditions if probes are placed on routines within the
kprobes files and routines used by the kprobes. For example if you put probe
on get_kprobe() routines, the system can hang while inserting probes on any
routine such as do_fork(). Because while inserting probes on do_fork(),
register_kprobes() routine grabs the kprobes spin lock and executes
get_kprobe() routine and to handle probe of get_kprobe(), kprobes_handler()
gets executed and tries to grab kprobes spin lock, and spins forever. This
patch avoids such possible race conditions by preventing probes on routines
within the kprobes file and routines used by kprobes.I have modified the patches as per Andi Kleen's suggestion to move kprobes
routines and other routines used by kprobes to a seperate section
.kprobes.text.Also moved page fault and exception handlers, general protection fault to
.kprobes.text section.These patches have been tested on i386, x86_64 and ppc64 architectures, also
compiled on ia64 and sparc64 architectures.Signed-off-by: Prasanna S Panchamukhi
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
29 Jul, 2005
1 commit
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Minor cleanup.
Move things into their include files, remove obsolete includes, fix
indentation, remove obsolete special cases etc.I also added the per cpu section to asm-generic/sections.h and fixed
init/main.c to use it.Signed-off-by: Andi Kleen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
06 May, 2005
1 commit
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The PPC32 kernel puts platform-specific functions into separate sections so
that unneeded parts of it can be freed when we've booted and actually
worked out what we're running on today.This makes kallsyms ignore those functions, because they're not between
_[se]text or _[se]inittext. Rather than teaching kallsyms about the
various pmac/chrp/etc sections, this patch adds '_[se]extratext' markers
for kallsyms.Signed-off-by: David Woodhouse
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
17 Apr, 2005
1 commit
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Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.Let it rip!
