On 18/03/19 11:33 AM, Ulf Hansson wrote: > + Arnd, Grygorii > > On Fri, 15 Feb 2019 at 20:17, Faiz Abbas <faiz_abbas@xxxxxx> wrote: >> >> sdhci.c has two bottom halves implemented. A threaded_irq for handling >> card insert/remove operations and a tasklet for finishing mmc requests. >> With the addition of external dma support, dmaengine APIs need to >> terminate in non-atomic context before unmapping the dma buffers. >> >> To facilitate this, remove the finish_tasklet and move the call of >> sdhci_request_done() to the threaded_irq() callback. Also move the >> interrupt result variable to sdhci_host so it can be populated from >> anywhere inside the sdhci_irq handler. >> >> Signed-off-by: Faiz Abbas <faiz_abbas@xxxxxx> > > Adrian, I think it makes sense to apply this patch, even if there is > very minor negative impact throughput wise. > > To me, it doesn't seems like MMC/SD/SDIO has good justification for > using tasklets, besides from the legacy point of view, of course. > Instead, I think we should try to move all mmc hosts into using > threaded IRQs. > > So, what do you think? Can you overlook the throughput drop and > instead we can try to recover this on top with other optimizations? I tend to favour good results as expressed here: https://lkml.org/lkml/2007/6/22/360 So I want to do optimization first. But performance is not the only problem with the patch. Give me a few days and I will see what I can come up with. > > Kind regards > Uffe > >> --- >> drivers/mmc/host/sdhci.c | 43 +++++++++++++++------------------------- >> drivers/mmc/host/sdhci.h | 2 +- >> 2 files changed, 17 insertions(+), 28 deletions(-) >> >> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c >> index eba9bcc92ad3..20ed09b896d7 100644 >> --- a/drivers/mmc/host/sdhci.c >> +++ b/drivers/mmc/host/sdhci.c >> @@ -1232,7 +1232,7 @@ static void __sdhci_finish_mrq(struct sdhci_host *host, struct mmc_request *mrq) >> >> WARN_ON(i >= SDHCI_MAX_MRQS); >> >> - tasklet_schedule(&host->finish_tasklet); >> + host->result = IRQ_WAKE_THREAD; >> } >> >> static void sdhci_finish_mrq(struct sdhci_host *host, struct mmc_request *mrq) >> @@ -2705,14 +2705,6 @@ static bool sdhci_request_done(struct sdhci_host *host) >> return false; >> } >> >> -static void sdhci_tasklet_finish(unsigned long param) >> -{ >> - struct sdhci_host *host = (struct sdhci_host *)param; >> - >> - while (!sdhci_request_done(host)) >> - ; >> -} >> - >> static void sdhci_timeout_timer(struct timer_list *t) >> { >> struct sdhci_host *host; >> @@ -2995,11 +2987,12 @@ static void sdhci_data_irq(struct sdhci_host *host, u32 intmask) >> >> static irqreturn_t sdhci_irq(int irq, void *dev_id) >> { >> - irqreturn_t result = IRQ_NONE; >> struct sdhci_host *host = dev_id; >> u32 intmask, mask, unexpected = 0; >> int max_loops = 16; >> >> + host->result = IRQ_NONE; >> + >> spin_lock(&host->lock); >> >> if (host->runtime_suspended && !sdhci_sdio_irq_enabled(host)) { >> @@ -3009,7 +3002,7 @@ static irqreturn_t sdhci_irq(int irq, void *dev_id) >> >> intmask = sdhci_readl(host, SDHCI_INT_STATUS); >> if (!intmask || intmask == 0xffffffff) { >> - result = IRQ_NONE; >> + host->result = IRQ_NONE; >> goto out; >> } >> >> @@ -3054,7 +3047,7 @@ static irqreturn_t sdhci_irq(int irq, void *dev_id) >> >> host->thread_isr |= intmask & (SDHCI_INT_CARD_INSERT | >> SDHCI_INT_CARD_REMOVE); >> - result = IRQ_WAKE_THREAD; >> + host->result = IRQ_WAKE_THREAD; >> } >> >> if (intmask & SDHCI_INT_CMD_MASK) >> @@ -3074,7 +3067,7 @@ static irqreturn_t sdhci_irq(int irq, void *dev_id) >> (host->ier & SDHCI_INT_CARD_INT)) { >> sdhci_enable_sdio_irq_nolock(host, false); >> host->thread_isr |= SDHCI_INT_CARD_INT; >> - result = IRQ_WAKE_THREAD; >> + host->result = IRQ_WAKE_THREAD; >> } >> >> intmask &= ~(SDHCI_INT_CARD_INSERT | SDHCI_INT_CARD_REMOVE | >> @@ -3087,8 +3080,8 @@ static irqreturn_t sdhci_irq(int irq, void *dev_id) >> sdhci_writel(host, intmask, SDHCI_INT_STATUS); >> } >> cont: >> - if (result == IRQ_NONE) >> - result = IRQ_HANDLED; >> + if (host->result == IRQ_NONE) >> + host->result = IRQ_HANDLED; >> >> intmask = sdhci_readl(host, SDHCI_INT_STATUS); >> } while (intmask && --max_loops); >> @@ -3101,7 +3094,7 @@ static irqreturn_t sdhci_irq(int irq, void *dev_id) >> sdhci_dumpregs(host); >> } >> >> - return result; >> + return host->result; >> } >> >> static irqreturn_t sdhci_thread_irq(int irq, void *dev_id) >> @@ -3131,6 +3124,12 @@ static irqreturn_t sdhci_thread_irq(int irq, void *dev_id) >> spin_unlock_irqrestore(&host->lock, flags); >> } >> >> + if (!isr) { >> + do { >> + isr = !sdhci_request_done(host); >> + } while (isr); >> + } >> + >> return isr ? IRQ_HANDLED : IRQ_NONE; >> } >> >> @@ -4212,12 +4211,6 @@ int __sdhci_add_host(struct sdhci_host *host) >> struct mmc_host *mmc = host->mmc; >> int ret; >> >> - /* >> - * Init tasklets. >> - */ >> - tasklet_init(&host->finish_tasklet, >> - sdhci_tasklet_finish, (unsigned long)host); >> - >> timer_setup(&host->timer, sdhci_timeout_timer, 0); >> timer_setup(&host->data_timer, sdhci_timeout_data_timer, 0); >> >> @@ -4230,7 +4223,7 @@ int __sdhci_add_host(struct sdhci_host *host) >> if (ret) { >> pr_err("%s: Failed to request IRQ %d: %d\n", >> mmc_hostname(mmc), host->irq, ret); >> - goto untasklet; >> + return ret; >> } >> >> ret = sdhci_led_register(host); >> @@ -4263,8 +4256,6 @@ int __sdhci_add_host(struct sdhci_host *host) >> sdhci_writel(host, 0, SDHCI_INT_ENABLE); >> sdhci_writel(host, 0, SDHCI_SIGNAL_ENABLE); >> free_irq(host->irq, host); >> -untasklet: >> - tasklet_kill(&host->finish_tasklet); >> >> return ret; >> } >> @@ -4326,8 +4317,6 @@ void sdhci_remove_host(struct sdhci_host *host, int dead) >> del_timer_sync(&host->timer); >> del_timer_sync(&host->data_timer); >> >> - tasklet_kill(&host->finish_tasklet); >> - >> if (!IS_ERR(mmc->supply.vqmmc)) >> regulator_disable(mmc->supply.vqmmc); >> >> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h >> index 6cc9a3c2ac66..624d5aa01995 100644 >> --- a/drivers/mmc/host/sdhci.h >> +++ b/drivers/mmc/host/sdhci.h >> @@ -554,7 +554,7 @@ struct sdhci_host { >> >> unsigned int desc_sz; /* ADMA descriptor size */ >> >> - struct tasklet_struct finish_tasklet; /* Tasklet structures */ >> + irqreturn_t result; /* Result of IRQ handler */ >> >> struct timer_list timer; /* Timer for timeouts */ >> struct timer_list data_timer; /* Timer for data timeouts */ >> -- >> 2.19.2 >> >
