The quilt patch titled
Subject: bit_spinlock: __always_inline (un)lock functions
has been removed from the -mm tree. Its filename was
bit_spinlock-__always_inline-unlock-functions.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: David Hildenbrand <david@xxxxxxxxxx>
Subject: bit_spinlock: __always_inline (un)lock functions
Date: Mon, 3 Mar 2025 17:30:03 +0100
The compiler might decide that it is a smart idea to not inline
bit_spin_lock(), primarily when a couple of functions in the same file end
up calling it. Especially when used in RMAP map/unmap code next, the
compiler sometimes decides to not inline, which is then observable in some
micro-benchmarks.
Let's simply flag all lock/unlock functions as __always_inline;
arch_test_and_set_bit_lock() and friends are already tagged like that (but
not test_and_set_bit_lock() for some reason).
If ever a problem, we could split it into a fast and a slow path, and only
force the fast path to be inlined. But there is nothing particularly
"big" here.
Link: https://lkml.kernel.org/r/20250303163014.1128035-11-david@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Andy Lutomirks^H^Hski <luto@xxxxxxxxxx>
Cc: Borislav Betkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Lance Yang <ioworker0@xxxxxxxxx>
Cc: Liam Howlett <liam.howlett@xxxxxxxxxx>
Cc: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
Cc: Matthew Wilcow (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Michal Koutn <mkoutny@xxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: tejun heo <tj@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Zefan Li <lizefan.x@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/bit_spinlock.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
--- a/include/linux/bit_spinlock.h~bit_spinlock-__always_inline-unlock-functions
+++ a/include/linux/bit_spinlock.h
@@ -13,7 +13,7 @@
* Don't use this unless you really need to: spin_lock() and spin_unlock()
* are significantly faster.
*/
-static inline void bit_spin_lock(int bitnum, unsigned long *addr)
+static __always_inline void bit_spin_lock(int bitnum, unsigned long *addr)
{
/*
* Assuming the lock is uncontended, this never enters
@@ -38,7 +38,7 @@ static inline void bit_spin_lock(int bit
/*
* Return true if it was acquired
*/
-static inline int bit_spin_trylock(int bitnum, unsigned long *addr)
+static __always_inline int bit_spin_trylock(int bitnum, unsigned long *addr)
{
preempt_disable();
#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
@@ -54,7 +54,7 @@ static inline int bit_spin_trylock(int b
/*
* bit-based spin_unlock()
*/
-static inline void bit_spin_unlock(int bitnum, unsigned long *addr)
+static __always_inline void bit_spin_unlock(int bitnum, unsigned long *addr)
{
#ifdef CONFIG_DEBUG_SPINLOCK
BUG_ON(!test_bit(bitnum, addr));
@@ -71,7 +71,7 @@ static inline void bit_spin_unlock(int b
* non-atomic version, which can be used eg. if the bit lock itself is
* protecting the rest of the flags in the word.
*/
-static inline void __bit_spin_unlock(int bitnum, unsigned long *addr)
+static __always_inline void __bit_spin_unlock(int bitnum, unsigned long *addr)
{
#ifdef CONFIG_DEBUG_SPINLOCK
BUG_ON(!test_bit(bitnum, addr));
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
