From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephane Eranian Date: Thu, 06 Dec 2007 17:15:27 +0000 Subject: Re: [PATCH 1/3] Rename TIF_PERFMON_WORK back to TIF_NOTIFY_RESUME Message-Id: <20071206171527.GG13304@frankl.hpl.hp.com> List-Id: References: <1196959881.6586.6.camel@elijah.suse.cz> In-Reply-To: <1196959881.6586.6.camel@elijah.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org Hello, On Thu, Dec 06, 2007 at 05:51:21PM +0100, Petr Tesarik wrote: > The RSE synchronization will need a TIF_ flag, but all work-to-be-done > bits are already used, so we'll have to multiplex TIF_NOTIFY_RESUME > again. > Yes, I knew this was coming. I think it is okay to multiplex on TIF_NOITFY_RESUME. However, I think it would be cleaner and likely more efficient to add yet another TIF flags for perfmon instead of adding the pfm_needs_checking field. That new TIF flag would not have to be in the low 7 bits. It could be higher because it would not be checked by the assembly code but rather in do_notify_resume_user(). The TIF limitation is just in the assembly code. Any comments? > Signed-off-by: Shaohua Li > Signed-off-by: Petr Tesarik > --- > arch/ia64/kernel/perfmon.c | 21 +++------------------ > arch/ia64/kernel/process.c | 9 +++++++++ > include/asm-ia64/thread_info.h | 9 ++++++--- > 3 files changed, 18 insertions(+), 21 deletions(-) > > diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c > index 73e7c2e..446e452 100644 > --- a/arch/ia64/kernel/perfmon.c > +++ b/arch/ia64/kernel/perfmon.c > @@ -586,21 +586,6 @@ pfm_put_task(struct task_struct *task) > } > > static inline void > -pfm_set_task_notify(struct task_struct *task) > -{ > - struct thread_info *info; > - > - info = (struct thread_info *) ((char *) task + IA64_TASK_SIZE); > - set_bit(TIF_PERFMON_WORK, &info->flags); > -} > - > -static inline void > -pfm_clear_task_notify(void) > -{ > - clear_thread_flag(TIF_PERFMON_WORK); > -} > - > -static inline void > pfm_reserve_page(unsigned long a) > { > SetPageReserved(vmalloc_to_page((void *)a)); > @@ -3724,7 +3709,7 @@ pfm_restart(pfm_context_t *ctx, void *ar > > PFM_SET_WORK_PENDING(task, 1); > > - pfm_set_task_notify(task); > + tsk_set_notify_resume(task); > > /* > * XXX: send reschedule if task runs on another CPU > @@ -5082,7 +5067,7 @@ pfm_handle_work(void) > > PFM_SET_WORK_PENDING(current, 0); > > - pfm_clear_task_notify(); > + tsk_clear_notify_resume(current); > > regs = task_pt_regs(current); > > @@ -5450,7 +5435,7 @@ pfm_overflow_handler(struct task_struct > * when coming from ctxsw, current still points to the > * previous task, therefore we must work with task and not current. > */ > - pfm_set_task_notify(task); > + tsk_set_notify_resume(task); > } > /* > * defer until state is changed (shorten spin window). the context is locked > diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c > index 2418289..94a92de 100644 > --- a/arch/ia64/kernel/process.c > +++ b/arch/ia64/kernel/process.c > @@ -155,6 +155,15 @@ show_regs (struct pt_regs *regs) > show_stack(NULL, NULL); > } > > +void tsk_clear_notify_resume(struct task_struct *tsk) > +{ > +#ifdef CONFIG_PERFMON > + if (tsk->thread.pfm_needs_checking) > + return; > +#endif > + clear_ti_thread_flag(task_thread_info(tsk), TIF_NOTIFY_RESUME); > +} > + > void > do_notify_resume_user (sigset_t *unused, struct sigscratch *scr, long in_syscall) > { > diff --git a/include/asm-ia64/thread_info.h b/include/asm-ia64/thread_info.h > index d16031e..5a2c479 100644 > --- a/include/asm-ia64/thread_info.h > +++ b/include/asm-ia64/thread_info.h > @@ -71,6 +71,9 @@ #define __HAVE_ARCH_TASK_STRUCT_ALLOCATO > #define alloc_task_struct() ((struct task_struct *)__get_free_pages(GFP_KERNEL | __GFP_COMP, KERNEL_STACK_SIZE_ORDER)) > #define free_task_struct(tsk) free_pages((unsigned long) (tsk), KERNEL_STACK_SIZE_ORDER) > > +#define tsk_set_notify_resume(tsk) \ > + set_ti_thread_flag(task_thread_info(tsk), TIF_NOTIFY_RESUME) > +extern void tsk_clear_notify_resume(struct task_struct *tsk); > #endif /* !__ASSEMBLY */ > > /* > @@ -85,7 +88,7 @@ #define TIF_SYSCALL_TRACE 2 /* syscall t > #define TIF_SYSCALL_AUDIT 3 /* syscall auditing active */ > #define TIF_SINGLESTEP 4 /* restore singlestep on return to user mode */ > #define TIF_RESTORE_SIGMASK 5 /* restore signal mask in do_signal() */ > -#define TIF_PERFMON_WORK 6 /* work for pfm_handle_work() */ > +#define TIF_NOTIFY_RESUME 6 /* resumption notification requested */ > #define TIF_POLLING_NRFLAG 16 /* true if poll_idle() is polling TIF_NEED_RESCHED */ > #define TIF_MEMDIE 17 > #define TIF_MCA_INIT 18 /* this task is processing MCA or INIT */ > @@ -97,7 +100,7 @@ #define _TIF_SYSCALL_AUDIT (1 << TIF_SYS > #define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP) > #define _TIF_SYSCALL_TRACEAUDIT (_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP) > #define _TIF_RESTORE_SIGMASK (1 << TIF_RESTORE_SIGMASK) > -#define _TIF_PERFMON_WORK (1 << TIF_PERFMON_WORK) > +#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME) > #define _TIF_SIGPENDING (1 << TIF_SIGPENDING) > #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) > #define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG) > @@ -106,7 +109,7 @@ #define _TIF_DB_DISABLED (1 << TIF_DB_DI > #define _TIF_FREEZE (1 << TIF_FREEZE) > > /* "work to do on user-return" bits */ > -#define TIF_ALLWORK_MASK (_TIF_SIGPENDING|_TIF_PERFMON_WORK|_TIF_SYSCALL_AUDIT|\ > +#define TIF_ALLWORK_MASK (_TIF_SIGPENDING|_TIF_NOTIFY_RESUME|_TIF_SYSCALL_AUDIT|\ > _TIF_NEED_RESCHED| _TIF_SYSCALL_TRACE|\ > _TIF_RESTORE_SIGMASK) > /* like TIF_ALLWORK_BITS but sans TIF_SYSCALL_TRACE or TIF_SYSCALL_AUDIT */ > > - > To unsubscribe from this list: send the line "unsubscribe linux-ia64" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- -Stephane