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https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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30d0b36828
On 64bit applications the VDSO is the only thing in segment 0. Since the VDSO is position independent we can remove the hint and let get_unmapped_area pick an area. This will mean the vdso will be near other mmaps and will share an SLB entry: 10000000-10001000 r-xp 00000000 08:06 5778459 /root/context_switch_64 10010000-10011000 r--p 00000000 08:06 5778459 /root/context_switch_64 10011000-10012000 rw-p 00001000 08:06 5778459 /root/context_switch_64 fffa92ae000-fffa92b0000 rw-p 00000000 00:00 0 fffa92b0000-fffa9453000 r-xp 00000000 08:06 4334051 /lib64/power6/libc-2.9.so fffa9453000-fffa9462000 ---p 001a3000 08:06 4334051 /lib64/power6/libc-2.9.so fffa9462000-fffa9466000 r--p 001a2000 08:06 4334051 /lib64/power6/libc-2.9.so fffa9466000-fffa947c000 rw-p 001a6000 08:06 4334051 /lib64/power6/libc-2.9.so fffa947c000-fffa9480000 rw-p 00000000 00:00 0 fffa9480000-fffa94a8000 r-xp 00000000 08:06 4333852 /lib64/ld-2.9.so fffa94b3000-fffa94b4000 rw-p 00000000 00:00 0 fffa94b4000-fffa94b7000 r-xp 00000000 00:00 0 [vdso] <----- here I am fffa94b7000-fffa94b8000 r--p 00027000 08:06 4333852 /lib64/ld-2.9.so fffa94b8000-fffa94bb000 rw-p 00028000 08:06 4333852 /lib64/ld-2.9.so fffa94bb000-fffa94bc000 rw-p 00000000 00:00 0 fffe4c10000-fffe4c25000 rw-p 00000000 00:00 0 [stack] On a microbenchmark that bounces a token between two 64bit processes over pipes and calls gettimeofday each iteration (to access the VDSO), our context switch rate goes from 268k to 277k ctx switches/sec (tested on a 4GHz POWER6). Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
78 lines
1.5 KiB
C
78 lines
1.5 KiB
C
#ifndef __PPC64_VDSO_H__
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#define __PPC64_VDSO_H__
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#ifdef __KERNEL__
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/* Default link addresses for the vDSOs */
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#define VDSO32_LBASE 0x100000
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#define VDSO64_LBASE 0x100000
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/* Default map addresses for 32bit vDSO */
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#define VDSO32_MBASE VDSO32_LBASE
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#define VDSO_VERSION_STRING LINUX_2.6.15
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/* Define if 64 bits VDSO has procedure descriptors */
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#undef VDS64_HAS_DESCRIPTORS
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#ifndef __ASSEMBLY__
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/* Offsets relative to thread->vdso_base */
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extern unsigned long vdso64_rt_sigtramp;
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extern unsigned long vdso32_sigtramp;
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extern unsigned long vdso32_rt_sigtramp;
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#else /* __ASSEMBLY__ */
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#ifdef __VDSO64__
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#ifdef VDS64_HAS_DESCRIPTORS
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#define V_FUNCTION_BEGIN(name) \
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.globl name; \
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.section ".opd","a"; \
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.align 3; \
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name: \
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.quad .name,.TOC.@tocbase,0; \
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.previous; \
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.globl .name; \
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.type .name,@function; \
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.name: \
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#define V_FUNCTION_END(name) \
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.size .name,.-.name;
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#define V_LOCAL_FUNC(name) (.name)
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#else /* VDS64_HAS_DESCRIPTORS */
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#define V_FUNCTION_BEGIN(name) \
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.globl name; \
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name: \
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#define V_FUNCTION_END(name) \
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.size name,.-name;
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#define V_LOCAL_FUNC(name) (name)
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#endif /* VDS64_HAS_DESCRIPTORS */
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#endif /* __VDSO64__ */
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#ifdef __VDSO32__
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#define V_FUNCTION_BEGIN(name) \
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.globl name; \
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.type name,@function; \
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name: \
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#define V_FUNCTION_END(name) \
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.size name,.-name;
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#define V_LOCAL_FUNC(name) (name)
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#endif /* __VDSO32__ */
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#endif /* __ASSEMBLY__ */
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#endif /* __KERNEL__ */
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#endif /* __PPC64_VDSO_H__ */
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