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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2016-10-25 12:21:44 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2016-11-11 16:37:40 +0100
commitc360192bf4a8dc72f102dd6a4e1bf8bd0b404cfa (patch)
treec54104bae43978dfe31e6fc2c9a4d996218379fd /arch/s390/include/asm/thread_info.h
parents390/bitops: use atomic primitives for bitops (diff)
downloadlinux-c360192bf4a8dc72f102dd6a4e1bf8bd0b404cfa.tar.xz
linux-c360192bf4a8dc72f102dd6a4e1bf8bd0b404cfa.zip
s390/preempt: move preempt_count to the lowcore
Convert s390 to use a field in the struct lowcore for the CPU preemption count. It is a bit cheaper to access a lowcore field compared to a thread_info variable and it removes the depencency on a task related structure. bloat-o-meter on the vmlinux image for the default configuration (CONFIG_PREEMPT_NONE=y) reports a small reduction in text size: add/remove: 0/0 grow/shrink: 18/578 up/down: 228/-5448 (-5220) A larger improvement is achieved with the default configuration but with CONFIG_PREEMPT=y and CONFIG_DEBUG_PREEMPT=n: add/remove: 2/6 grow/shrink: 59/4477 up/down: 1618/-228762 (-227144) Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/include/asm/thread_info.h')
-rw-r--r--arch/s390/include/asm/thread_info.h2
1 files changed, 0 insertions, 2 deletions
diff --git a/arch/s390/include/asm/thread_info.h b/arch/s390/include/asm/thread_info.h
index f15c0398c363..933794150e5b 100644
--- a/arch/s390/include/asm/thread_info.h
+++ b/arch/s390/include/asm/thread_info.h
@@ -34,7 +34,6 @@ struct thread_info {
unsigned long flags; /* low level flags */
unsigned long sys_call_table; /* System call table address */
unsigned int cpu; /* current CPU */
- int preempt_count; /* 0 => preemptable, <0 => BUG */
unsigned int system_call;
__u64 user_timer;
__u64 system_timer;
@@ -49,7 +48,6 @@ struct thread_info {
.task = &tsk, \
.flags = 0, \
.cpu = 0, \
- .preempt_count = INIT_PREEMPT_COUNT, \
}
#define init_thread_info (init_thread_union.thread_info)