Florian reported that all of kernel/sched/ is rebuild when
CONFIG_BLK_DEV_INITRD is changed, which, while not a bug is
unexpected. This is due to us including vmlinux.lds.h.
Jakub explained that the problem is that we put the alignment
requirement on the type instead of on a variable. Type alignment is a
minimum, the compiler is free to pick any larger alignment for a
specific instance of the type (eg. the variable).
So force the type alignment on all individual variable definitions and
remove the undesired dependency on vmlinux.lds.h.
Fixes:
85c2ce9104eb ("sched, vmlinux.lds: Increase STRUCT_ALIGNMENT to 64 bytes for GCC-4.9")
Reported-by: Florian Fainelli <f.fainelli@gmail.com>
Suggested-by: Jakub Jelinek <jakub@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
}
}
-const struct sched_class dl_sched_class
- __section("__dl_sched_class") = {
+DEFINE_SCHED_CLASS(dl) = {
+
.enqueue_task = enqueue_task_dl,
.dequeue_task = dequeue_task_dl,
.yield_task = yield_task_dl,
/*
* All the scheduling class methods:
*/
-const struct sched_class fair_sched_class
- __section("__fair_sched_class") = {
+DEFINE_SCHED_CLASS(fair) = {
+
.enqueue_task = enqueue_task_fair,
.dequeue_task = dequeue_task_fair,
.yield_task = yield_task_fair,
/*
* Simple, special scheduling class for the per-CPU idle tasks:
*/
-const struct sched_class idle_sched_class
- __section("__idle_sched_class") = {
+DEFINE_SCHED_CLASS(idle) = {
+
/* no enqueue/yield_task for idle tasks */
/* dequeue is not valid, we print a debug message there: */
return 0;
}
-const struct sched_class rt_sched_class
- __section("__rt_sched_class") = {
+DEFINE_SCHED_CLASS(rt) = {
+
.enqueue_task = enqueue_task_rt,
.dequeue_task = dequeue_task_rt,
.yield_task = yield_task_rt,
#include <linux/tsacct_kern.h>
#include <asm/tlb.h>
-#include <asm-generic/vmlinux.lds.h>
#ifdef CONFIG_PARAVIRT
# include <asm/paravirt.h>
#ifdef CONFIG_FAIR_GROUP_SCHED
void (*task_change_group)(struct task_struct *p, int type);
#endif
-} __aligned(STRUCT_ALIGNMENT); /* STRUCT_ALIGN(), vmlinux.lds.h */
+};
static inline void put_prev_task(struct rq *rq, struct task_struct *prev)
{
next->sched_class->set_next_task(rq, next, false);
}
+
+/*
+ * Helper to define a sched_class instance; each one is placed in a separate
+ * section which is ordered by the linker script:
+ *
+ * include/asm-generic/vmlinux.lds.h
+ *
+ * Also enforce alignment on the instance, not the type, to guarantee layout.
+ */
+#define DEFINE_SCHED_CLASS(name) \
+const struct sched_class name##_sched_class \
+ __aligned(__alignof__(struct sched_class)) \
+ __section("__" #name "_sched_class")
+
/* Defined in include/asm-generic/vmlinux.lds.h */
extern struct sched_class __begin_sched_classes[];
extern struct sched_class __end_sched_classes[];
/*
* Simple, special scheduling class for the per-CPU stop tasks:
*/
-const struct sched_class stop_sched_class
- __section("__stop_sched_class") = {
+DEFINE_SCHED_CLASS(stop) = {
.enqueue_task = enqueue_task_stop,
.dequeue_task = dequeue_task_stop,