diff options
| 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 | |
| parent | 1993dbc7e09a7ffdd98975589aa83387928e9fe7 (diff) | |
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')
| -rw-r--r-- | arch/s390/kernel/asm-offsets.c | 2 | ||||
| -rw-r--r-- | arch/s390/kernel/early.c | 1 | ||||
| -rw-r--r-- | arch/s390/kernel/entry.S | 2 | ||||
| -rw-r--r-- | arch/s390/kernel/setup.c | 1 |
4 files changed, 4 insertions, 2 deletions
diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c index ec16cec6bcd4..6be10e490982 100644 --- a/arch/s390/kernel/asm-offsets.c +++ b/arch/s390/kernel/asm-offsets.c @@ -43,7 +43,6 @@ int main(void) OFFSET(__TI_flags, thread_info, flags); OFFSET(__TI_sysc_table, thread_info, sys_call_table); OFFSET(__TI_cpu, thread_info, cpu); - OFFSET(__TI_precount, thread_info, preempt_count); OFFSET(__TI_user_timer, thread_info, user_timer); OFFSET(__TI_system_timer, thread_info, system_timer); OFFSET(__TI_last_break, thread_info, last_break); @@ -175,6 +174,7 @@ int main(void) OFFSET(__LC_PERCPU_OFFSET, lowcore, percpu_offset); OFFSET(__LC_VDSO_PER_CPU, lowcore, vdso_per_cpu_data); OFFSET(__LC_MACHINE_FLAGS, lowcore, machine_flags); + OFFSET(__LC_PREEMPT_COUNT, lowcore, preempt_count); OFFSET(__LC_GMAP, lowcore, gmap); OFFSET(__LC_PASTE, lowcore, paste); /* software defined ABI-relevant lowcore locations 0xe00 - 0xe20 */ 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) diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S index 49a30737adde..3f4a1638a700 100644 --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -626,7 +626,7 @@ ENTRY(io_int_handler) jo .Lio_work_user # yes -> do resched & signal #ifdef CONFIG_PREEMPT # check for preemptive scheduling - icm %r0,15,__TI_precount(%r12) + icm %r0,15,__LC_PREEMPT_COUNT jnz .Lio_restore # preemption is disabled TSTMSK __TI_flags(%r12),_TIF_NEED_RESCHED jno .Lio_restore diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c index 7f7ba5f23f13..268d6c1b651f 100644 --- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -333,6 +333,7 @@ static void __init setup_lowcore(void) lc->thread_info = (unsigned long) &init_thread_union; lc->lpp = LPP_MAGIC; lc->machine_flags = S390_lowcore.machine_flags; + lc->preempt_count = S390_lowcore.preempt_count; lc->stfl_fac_list = S390_lowcore.stfl_fac_list; memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list, MAX_FACILITY_BIT/8); |