Eric Dumazet 231bed2058 [PATCH] No need to protect current->group_info in sys_getgroups(), in_group_p() and in_egroup_p() ... While doing some benchmarks of an Apache/PHP SMP server, I noticed high oprofile numbers in in_group_p() and _atomic_dec_and_lock(). rank percent 1 4.8911 % __link_path_walk 2 4.8503 % __d_lookup *3 4.2911 % _atomic_dec_and_lock 4 3.9307 % __copy_to_user_ll 5 4.9004 % sysenter_past_esp *6 3.3248 % in_group_p It appears that in_group_p() does an uncessary get_group_info(current->group_info); /* atomic_inc() */ ... /* access current->group_info */ put_group_info(current->group_info); /* _atomic_dec_and_lock */ It is not necessary to do this, because the current task holds a reference on its own group_info, and this reference cannot change during the lookup. This patch deletes the get_group_info()/put_group_info() pair from sys_getgroups(), in_group_p() and in_egroup_p() functions. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Cc: Tim Hockin <thockin@hockin.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>		2006-03-25 08:22:58 -08:00
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irq
power
.gitignore
acct.c
audit.c
auditsc.c
capability.c
compat.c
configs.c
cpu.c
cpuset.c
dma.c
exec_domain.c
exit.c
extable.c
fork.c
futex.c
hrtimer.c
intermodule.c
itimer.c
kallsyms.c
Kconfig.hz
Kconfig.preempt
kexec.c
kfifo.c
kmod.c
kprobes.c
ksysfs.c
kthread.c
Makefile
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mutex-debug.c
mutex-debug.h
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panic.c
params.c
pid.c
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printk.c
profile.c
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rcutorture.c
relay.c
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seccomp.c
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softirq.c
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sys_ni.c
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uid16.c
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