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| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2016-10-25 12:21:44 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2016-11-11 16:37:40 +0100 |
| commit | c360192bf4a8dc72f102dd6a4e1bf8bd0b404cfa (patch) | |
| tree | c54104bae43978dfe31e6fc2c9a4d996218379fd /arch/s390/kernel/early.c | |
| parent | 1993dbc7e09a7ffdd98975589aa83387928e9fe7 (diff) | |
| download | lwn-c360192bf4a8dc72f102dd6a4e1bf8bd0b404cfa.tar.gz lwn-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/kernel/early.c')
| -rw-r--r-- | arch/s390/kernel/early.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c index 39d03a7a3354..9cd85adaa7c1 100644 --- a/arch/s390/kernel/early.c +++ b/arch/s390/kernel/early.c @@ -293,6 +293,7 @@ static noinline __init void setup_lowcore_early(void) psw.addr = (unsigned long) s390_base_pgm_handler; S390_lowcore.program_new_psw = psw; s390_base_pgm_handler_fn = early_pgm_check_handler; + S390_lowcore.preempt_count = INIT_PREEMPT_COUNT; } static noinline __init void setup_facility_list(void) |