spinlock: lockbreak cleanup
The break_lock data structure and code for spinlocks is quite nasty.
Not only does it double the size of a spinlock but it changes locking to
a potentially less optimal trylock.
Put all of that under CONFIG_GENERIC_LOCKBREAK, and introduce a
__raw_spin_is_contended that uses the lock data itself to determine whether
there are waiters on the lock, to be used if CONFIG_GENERIC_LOCKBREAK is
not set.
Rename need_lockbreak to spin_needbreak, make it use spin_is_contended to
decouple it from the spinlock implementation, and make it typesafe (rwlocks
do not have any need_lockbreak sites -- why do they even get bloated up
with that break_lock then?).
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/mm/memory.c b/mm/memory.c
index 4b0144b..673ebbf 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -513,8 +513,7 @@
if (progress >= 32) {
progress = 0;
if (need_resched() ||
- need_lockbreak(src_ptl) ||
- need_lockbreak(dst_ptl))
+ spin_needbreak(src_ptl) || spin_needbreak(dst_ptl))
break;
}
if (pte_none(*src_pte)) {
@@ -853,7 +852,7 @@
tlb_finish_mmu(*tlbp, tlb_start, start);
if (need_resched() ||
- (i_mmap_lock && need_lockbreak(i_mmap_lock))) {
+ (i_mmap_lock && spin_needbreak(i_mmap_lock))) {
if (i_mmap_lock) {
*tlbp = NULL;
goto out;
@@ -1768,8 +1767,7 @@
restart_addr = zap_page_range(vma, start_addr,
end_addr - start_addr, details);
- need_break = need_resched() ||
- need_lockbreak(details->i_mmap_lock);
+ need_break = need_resched() || spin_needbreak(details->i_mmap_lock);
if (restart_addr >= end_addr) {
/* We have now completed this vma: mark it so */