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authorLinus Torvalds <torvalds@linux-foundation.org>2023-02-21 04:18:23 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2023-02-21 04:18:23 +0300
commit6e649d08568220ee88deef0a1ad8b3a935420cf2 (patch)
tree421310a204dfa8477a2fd4afe15466ed078726c7 /arch
parentdb77b8502a4071a59c9424d95f87fe20bdb52c3a (diff)
parent3b4863fa5b7dd50dab1b10abbed938efd203752f (diff)
downloadlinux-6e649d08568220ee88deef0a1ad8b3a935420cf2.tar.xz
Merge tag 'locking-core-2023-02-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar: - rwsem micro-optimizations - spinlock micro-optimizations - cleanups, simplifications * tag 'locking-core-2023-02-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: vduse: Remove include of rwlock.h locking/lockdep: Remove lockdep_init_map_crosslock. x86/ACPI/boot: Use try_cmpxchg() in __acpi_{acquire,release}_global_lock() x86/PAT: Use try_cmpxchg() in set_page_memtype() locking/rwsem: Disable preemption in all down_write*() and up_write() code paths locking/rwsem: Disable preemption in all down_read*() and up_read() code paths locking/rwsem: Prevent non-first waiter from spinning in down_write() slowpath locking/qspinlock: Micro-optimize pending state waiting for unlock
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/acpi/boot.c16
-rw-r--r--arch/x86/mm/pat/memtype.c4
2 files changed, 10 insertions, 10 deletions
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 907cc98b1938..4177577c173b 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -1840,23 +1840,23 @@ early_param("acpi_sci", setup_acpi_sci);
int __acpi_acquire_global_lock(unsigned int *lock)
{
- unsigned int old, new, val;
+ unsigned int old, new;
+
+ old = READ_ONCE(*lock);
do {
- old = *lock;
new = (((old & ~0x3) + 2) + ((old >> 1) & 0x1));
- val = cmpxchg(lock, old, new);
- } while (unlikely (val != old));
+ } while (!try_cmpxchg(lock, &old, new));
return ((new & 0x3) < 3) ? -1 : 0;
}
int __acpi_release_global_lock(unsigned int *lock)
{
- unsigned int old, new, val;
+ unsigned int old, new;
+
+ old = READ_ONCE(*lock);
do {
- old = *lock;
new = old & ~0x3;
- val = cmpxchg(lock, old, new);
- } while (unlikely (val != old));
+ } while (!try_cmpxchg(lock, &old, new));
return old & 0x1;
}
diff --git a/arch/x86/mm/pat/memtype.c b/arch/x86/mm/pat/memtype.c
index 46de9cf5c91d..004b37f026d1 100644
--- a/arch/x86/mm/pat/memtype.c
+++ b/arch/x86/mm/pat/memtype.c
@@ -159,10 +159,10 @@ static inline void set_page_memtype(struct page *pg,
break;
}
+ old_flags = READ_ONCE(pg->flags);
do {
- old_flags = pg->flags;
new_flags = (old_flags & _PGMT_CLEAR_MASK) | memtype_flags;
- } while (cmpxchg(&pg->flags, old_flags, new_flags) != old_flags);
+ } while (!try_cmpxchg(&pg->flags, &old_flags, new_flags));
}
#else
static inline enum page_cache_mode get_page_memtype(struct page *pg)