On Wed, Mar 06, 2019 at 07:49:36PM +0800, Yafang Shao wrote:
$ grep SCHEDSTAT defconfig-build/.config
# CONFIG_SCHEDSTATS is not set
$ obbjdump -dr defconfig-build/kernel/sched/fair.o | awk '/>:$/ { F=$2 }
/sched_stat/ { print F " " $0 }'
<update_curr>: 24cd: R_X86_64_32S
__tracepoint_sched_stat_runtime+0x28
<update_curr>: 24d9: R_X86_64_PC32
__tracepoint_sched_stat_runtime+0x24
$ patch -p1 < foo
patching file kernel/sched/fair.c
$ make O=defconfig-build kernel/sched/
make[1]: Entering directory '/usr/src/linux-2.6/defconfig-build'
Using .. as source for kernel
GEN Makefile
CALL ../scripts/checksyscalls.sh
CALL ../scripts/atomic/check-atomics.sh
DESCEND objtool
CC kernel/sched/fair.o
AR kernel/sched/built-in.a
make[1]: Leaving directory '/usr/src/linux-2.6/defconfig-build'
$ objdump -dr defconfig-build/kernel/sched/fair.o | awk '/>:$/ { F=$2 }
/sched_stat/ { print F " " $0 }'
$ cat foo
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 8213ff6e365d..6e5ceec3b662 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -839,7 +839,8 @@ static void update_curr(struct cfs_rq *cfs_rq)
if (entity_is_task(curr)) {
struct task_struct *curtask = task_of(curr);
- trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime);
+ if (schedstat_enabled())
+ trace_sched_stat_runtime(curtask, delta_exec,
curr->vruntime);
cgroup_account_cputime(curtask, delta_exec);
account_group_exec_runtime(curtask, delta_exec);
}
_1_ line, where you wanted to add _6_ ugly #ifdefs
