On Monday 29 January 2007 20:48, Maynard Johnson wrote: > Subject: Enable SPU switch notification to detect currently active SPU tasks. > > From: Maynard Johnson <[EMAIL PROTECTED]> > > This patch adds to the capability of spu_switch_event_register so that the > caller is also notified of currently active SPU tasks. It also exports > spu_switch_event_register and spu_switch_event_unregister. > > Signed-off-by: Maynard Johnson <[EMAIL PROTECTED]>
I looked through it again, and think I found a serious bug, but that should be easy enough to solve: > +static void notify_spus_active(void) > +{ > + int node; > + /* Wake up the active spu_contexts. When the awakened processes > + * sees their notify_active flag is set, they will call > + * spu_switch_notify(); > + */ > + for (node = 0; node < MAX_NUMNODES; node++) { > + struct spu *spu; > + mutex_lock(&spu_prio->active_mutex[node]); > + list_for_each_entry(spu, &spu_prio->active_list[node], list) > { > + struct spu_context *ctx = spu->ctx; [side note] There is a small whitespace breakage in here, please make sure you always use tabs for indenting, not space characters. [/side note] > @@ -45,9 +45,10 @@ > u64 pte_fault; > > *stat = ctx->ops->status_read(ctx); > - if (ctx->state != SPU_STATE_RUNNABLE) > - return 1; > + > spu = ctx->spu; > + if (ctx->state != SPU_STATE_RUNNABLE || spu->notify_active) > + return 1; > pte_fault = spu->dsisr & > (MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED); > return (!(*stat & 0x1) || pte_fault || spu->class_0_pending) ? 1 : 0; > @@ -305,6 +306,7 @@ > u32 *npc, u32 *event) > { > int ret; > + struct spu * spu; > u32 status; > > if (down_interruptible(&ctx->run_sema)) > @@ -318,8 +320,16 @@ > > do { > ret = spufs_wait(ctx->stop_wq, spu_stopped(ctx, &status)); > + spu = ctx->spu; > if (unlikely(ret)) > break; > + if (unlikely(spu->notify_active)) { > + spu->notify_active = 0; > + if (!(status & SPU_STATUS_STOPPED_BY_STOP)) { > + spu_switch_notify(spu, ctx); > + continue; > + } > + } This is before spu_reacquire_runnable, so in case the spu got preempted at the same time when oprofile was enabled, ctx->spu is NULL, and you can't load the notify_active flag from it. On solution would be to move the notify_active flag from ctx->spu into ctx itself, but maybe there are other ways to solve this. Thanks, Arnd <>< - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/