Messages in this thread | | | Date | Tue, 9 Aug 2022 19:09:05 -0400 | Subject | Re: [PATCH] locking: Add __lockfunc to slow path functions | From | Waiman Long <> |
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On 8/9/22 17:13, Namhyung Kim wrote: > Hello, > > On Tue, Aug 9, 2022 at 8:05 AM Waiman Long <longman@redhat.com> wrote: >> On 8/8/22 13:59, Namhyung Kim wrote: >>> So that we can skip the functions in the perf lock contention and other >>> places like /proc/PID/wchan. >>> >>> Signed-off-by: Namhyung Kim <namhyung@kernel.org> >>> --- >>> kernel/locking/qrwlock.c | 4 ++-- >>> kernel/locking/qspinlock.c | 2 +- >>> 2 files changed, 3 insertions(+), 3 deletions(-) >>> >>> diff --git a/kernel/locking/qrwlock.c b/kernel/locking/qrwlock.c >>> index 2e1600906c9f..d2ef312a8611 100644 >>> --- a/kernel/locking/qrwlock.c >>> +++ b/kernel/locking/qrwlock.c >>> @@ -18,7 +18,7 @@ >>> * queued_read_lock_slowpath - acquire read lock of a queued rwlock >>> * @lock: Pointer to queued rwlock structure >>> */ >>> -void queued_read_lock_slowpath(struct qrwlock *lock) >>> +void __lockfunc queued_read_lock_slowpath(struct qrwlock *lock) >>> { >>> /* >>> * Readers come here when they cannot get the lock without waiting >>> @@ -63,7 +63,7 @@ EXPORT_SYMBOL(queued_read_lock_slowpath); >>> * queued_write_lock_slowpath - acquire write lock of a queued rwlock >>> * @lock : Pointer to queued rwlock structure >>> */ >>> -void queued_write_lock_slowpath(struct qrwlock *lock) >>> +void __lockfunc queued_write_lock_slowpath(struct qrwlock *lock) >>> { >>> int cnts; >>> >>> diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c >>> index 65a9a10caa6f..2b23378775fe 100644 >>> --- a/kernel/locking/qspinlock.c >>> +++ b/kernel/locking/qspinlock.c >>> @@ -313,7 +313,7 @@ static __always_inline u32 __pv_wait_head_or_lock(struct qspinlock *lock, >>> * contended : (*,x,y) +--> (*,0,0) ---> (*,0,1) -' : >>> * queue : ^--' : >>> */ >>> -void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) >>> +void __lockfunc queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) >>> { >>> struct mcs_spinlock *prev, *next, *node; >>> u32 old, tail; >> >> For completeness, I think you should also add it to the >> __pv_queued_spin_unlock() and __pv_queued_spin_unlock_slowpath() >> function in kernel/locking/qspinlock_paravirt.h. Perhaps even the >> assembly code in arch/x86/include/asm/qspinlock_paravirt.h. > Thanks for your comment. I'm not sure about the asm part, will this be enough? > > --- a/arch/x86/include/asm/qspinlock_paravirt.h > +++ b/arch/x86/include/asm/qspinlock_paravirt.h > @@ -36,7 +36,7 @@ PV_CALLEE_SAVE_REGS_THUNK(__pv_queued_spin_unlock_slowpath); > * rsi = lockval (second argument) > * rdx = internal variable (set to 0) > */ > -asm (".pushsection .text;" > +asm (".pushsection .spinlock.text;" > ".globl " PV_UNLOCK ";" > ".type " PV_UNLOCK ", @function;" > ".align 4,0x90;" > That is what I meant. However, you should also a comment saying that the use of .spinlock.text section is equivalent to the use of __lockfunc on an equivalent C function to make it clear. Also add the __lockfunc to the pseudo code in the comment section.
Cheers, Longman
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