| Message ID | 1460041951-22347-11-git-send-email-mhocko@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
* Michal Hocko <mhocko@kernel.org> wrote: > From: Michal Hocko <mhocko@suse.com> > > which uses the same fast path as __down_write except it falls back to > call_rwsem_down_write_failed_killable slow path and return -EINTR if > killed. To prevent from code duplication extract the skeleton of > __down_write into a helper macro which just takes the semaphore > and the slow path function to be called. > > Signed-off-by: Michal Hocko <mhocko@suse.com> > --- > arch/x86/include/asm/rwsem.h | 41 ++++++++++++++++++++++++++++------------- > arch/x86/lib/rwsem.S | 8 ++++++++ > 2 files changed, 36 insertions(+), 13 deletions(-) > > diff --git a/arch/x86/include/asm/rwsem.h b/arch/x86/include/asm/rwsem.h > index d79a218675bc..4c3d90dbe89a 100644 > --- a/arch/x86/include/asm/rwsem.h > +++ b/arch/x86/include/asm/rwsem.h > @@ -99,21 +99,36 @@ static inline int __down_read_trylock(struct rw_semaphore *sem) > /* > * lock for writing > */ > +#define ____down_write(sem, slow_path) \ > +({ \ > + long tmp; \ > + struct rw_semaphore* ret = sem; \ > + asm volatile("# beginning down_write\n\t" \ > + LOCK_PREFIX " xadd %1,(%2)\n\t" \ > + /* adds 0xffff0001, returns the old value */ \ > + " test " __ASM_SEL(%w1,%k1) "," __ASM_SEL(%w1,%k1) "\n\t" \ > + /* was the active mask 0 before? */\ > + " jz 1f\n" \ > + " call " slow_path "\n" \ > + "1:\n" \ > + "# ending down_write" \ > + : "+m" (sem->count), "=d" (tmp), "+a" (ret) \ > + : "a" (sem), "1" (RWSEM_ACTIVE_WRITE_BIAS) \ > + : "memory", "cc"); \ > + ret; \ > +}) > + > static inline void __down_write(struct rw_semaphore *sem) > { > - long tmp; > - asm volatile("# beginning down_write\n\t" > - LOCK_PREFIX " xadd %1,(%2)\n\t" > - /* adds 0xffff0001, returns the old value */ > - " test " __ASM_SEL(%w1,%k1) "," __ASM_SEL(%w1,%k1) "\n\t" > - /* was the active mask 0 before? */ > - " jz 1f\n" > - " call call_rwsem_down_write_failed\n" > - "1:\n" > - "# ending down_write" > - : "+m" (sem->count), "=d" (tmp) > - : "a" (sem), "1" (RWSEM_ACTIVE_WRITE_BIAS) > - : "memory", "cc"); > + ____down_write(sem, "call_rwsem_down_write_failed"); > +} > + > +static inline int __down_write_killable(struct rw_semaphore *sem) > +{ > + if (IS_ERR(____down_write(sem, "call_rwsem_down_write_failed_killable"))) > + return -EINTR; > + > + return 0; > } > > /* > diff --git a/arch/x86/lib/rwsem.S b/arch/x86/lib/rwsem.S > index 40027db99140..d1a1397e1fb3 100644 > --- a/arch/x86/lib/rwsem.S > +++ b/arch/x86/lib/rwsem.S > @@ -101,6 +101,14 @@ ENTRY(call_rwsem_down_write_failed) > ret > ENDPROC(call_rwsem_down_write_failed) > > +ENTRY(call_rwsem_down_write_failed_killable) > + save_common_regs > + movq %rax,%rdi > + call rwsem_down_write_failed_killable > + restore_common_regs > + ret > +ENDPROC(call_rwsem_down_write_failed_killable) Got this objtool warning on x86-64 allyesconfig: arch/x86/lib/rwsem.o: warning: objtool: call_rwsem_down_write_failed_killable()+0xe: call without frame pointer save/setup Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-sh" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed 13-04-16 11:08:30, Ingo Molnar wrote: > > * Michal Hocko <mhocko@kernel.org> wrote: [...] > > +ENTRY(call_rwsem_down_write_failed_killable) > > + save_common_regs > > + movq %rax,%rdi > > + call rwsem_down_write_failed_killable > > + restore_common_regs > > + ret > > +ENDPROC(call_rwsem_down_write_failed_killable) > > Got this objtool warning on x86-64 allyesconfig: > > arch/x86/lib/rwsem.o: warning: objtool: call_rwsem_down_write_failed_killable()+0xe: call without frame pointer save/setup Peter has already pointed that out. This is because the 4.5 which I was basing my work on doesn't have 3387a535ce62 ("x86/asm: Create stack frames in rwsem functions") which shown up in 4.6-rc1. He mentioned to add the missing FRAME_{BEGIN,END} during the merge AFAIR. Does that sound reasonable to you or should I rebase?
* Michal Hocko <mhocko@kernel.org> wrote: > On Wed 13-04-16 11:08:30, Ingo Molnar wrote: > > > > * Michal Hocko <mhocko@kernel.org> wrote: > [...] > > > +ENTRY(call_rwsem_down_write_failed_killable) > > > + save_common_regs > > > + movq %rax,%rdi > > > + call rwsem_down_write_failed_killable > > > + restore_common_regs > > > + ret > > > +ENDPROC(call_rwsem_down_write_failed_killable) > > > > Got this objtool warning on x86-64 allyesconfig: > > > > arch/x86/lib/rwsem.o: warning: objtool: call_rwsem_down_write_failed_killable()+0xe: call without frame pointer save/setup > > Peter has already pointed that out. This is because the 4.5 which I was > basing my work on doesn't have 3387a535ce62 ("x86/asm: Create stack > frames in rwsem functions") which shown up in 4.6-rc1. He mentioned to > add the missing FRAME_{BEGIN,END} during the merge AFAIR. > > Does that sound reasonable to you or should I rebase? I'm testing your patches today, if they are otherwise OK then please send a delta patch against the tip:locking/rwsem tree I'll push out. Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-sh" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/x86/include/asm/rwsem.h b/arch/x86/include/asm/rwsem.h index d79a218675bc..4c3d90dbe89a 100644 --- a/arch/x86/include/asm/rwsem.h +++ b/arch/x86/include/asm/rwsem.h @@ -99,21 +99,36 @@ static inline int __down_read_trylock(struct rw_semaphore *sem) /* * lock for writing */ +#define ____down_write(sem, slow_path) \ +({ \ + long tmp; \ + struct rw_semaphore* ret = sem; \ + asm volatile("# beginning down_write\n\t" \ + LOCK_PREFIX " xadd %1,(%2)\n\t" \ + /* adds 0xffff0001, returns the old value */ \ + " test " __ASM_SEL(%w1,%k1) "," __ASM_SEL(%w1,%k1) "\n\t" \ + /* was the active mask 0 before? */\ + " jz 1f\n" \ + " call " slow_path "\n" \ + "1:\n" \ + "# ending down_write" \ + : "+m" (sem->count), "=d" (tmp), "+a" (ret) \ + : "a" (sem), "1" (RWSEM_ACTIVE_WRITE_BIAS) \ + : "memory", "cc"); \ + ret; \ +}) + static inline void __down_write(struct rw_semaphore *sem) { - long tmp; - asm volatile("# beginning down_write\n\t" - LOCK_PREFIX " xadd %1,(%2)\n\t" - /* adds 0xffff0001, returns the old value */ - " test " __ASM_SEL(%w1,%k1) "," __ASM_SEL(%w1,%k1) "\n\t" - /* was the active mask 0 before? */ - " jz 1f\n" - " call call_rwsem_down_write_failed\n" - "1:\n" - "# ending down_write" - : "+m" (sem->count), "=d" (tmp) - : "a" (sem), "1" (RWSEM_ACTIVE_WRITE_BIAS) - : "memory", "cc"); + ____down_write(sem, "call_rwsem_down_write_failed"); +} + +static inline int __down_write_killable(struct rw_semaphore *sem) +{ + if (IS_ERR(____down_write(sem, "call_rwsem_down_write_failed_killable"))) + return -EINTR; + + return 0; } /* diff --git a/arch/x86/lib/rwsem.S b/arch/x86/lib/rwsem.S index 40027db99140..d1a1397e1fb3 100644 --- a/arch/x86/lib/rwsem.S +++ b/arch/x86/lib/rwsem.S @@ -101,6 +101,14 @@ ENTRY(call_rwsem_down_write_failed) ret ENDPROC(call_rwsem_down_write_failed) +ENTRY(call_rwsem_down_write_failed_killable) + save_common_regs + movq %rax,%rdi + call rwsem_down_write_failed_killable + restore_common_regs + ret +ENDPROC(call_rwsem_down_write_failed_killable) + ENTRY(call_rwsem_wake) /* do nothing if still outstanding active readers */ __ASM_HALF_SIZE(dec) %__ASM_HALF_REG(dx)