All 5 IRQ handlers of the driver are requested as threaded interrupt handlers. However, only 1 handler can block. The remaining 4 handlers defer the actual handling to a workqueue. Hence, 4 of 5 IRQ handlers have a considerable overhead, since they are executed in a kernel thread to schedule another kernel thread (workqueue).
This change splits up the 5 interrupt handlers into top halves (_th) and bottom halves (_bh) and resolves the aforementioned overhead by only requesting threaded interrupts (i.e., bottom halves) when necessary. Signed-off-by: Valentin Rothberg <[email protected]> --- Due to the lack of hardware I cannot test this change. I discovered this issue with scripts/coccinelle/misc/irqf_oneshot.cocci since the threaded interrupts were not requested with IRQF_ONESHOT. By looking closer I saw the issue of this change. --- drivers/power/ab8500_fg.c | 46 +++++++++++++++++++++++++++++++++------------- 1 file changed, 33 insertions(+), 13 deletions(-) diff --git a/drivers/power/ab8500_fg.c b/drivers/power/ab8500_fg.c index c908658..dcd0901 100644 --- a/drivers/power/ab8500_fg.c +++ b/drivers/power/ab8500_fg.c @@ -3062,11 +3062,14 @@ static int ab8500_fg_remove(struct platform_device *pdev) } /* ab8500 fg driver interrupts and their respective isr */ -static struct ab8500_fg_interrupts ab8500_fg_irq[] = { +static struct ab8500_fg_interrupts ab8500_fg_irq_th[] = { {"NCONV_ACCU", ab8500_fg_cc_convend_handler}, {"BATT_OVV", ab8500_fg_batt_ovv_handler}, {"LOW_BAT_F", ab8500_fg_lowbatf_handler}, {"CC_INT_CALIB", ab8500_fg_cc_int_calib_handler}, +}; + +static struct ab8500_fg_interrupts ab8500_fg_irq_bh[] = { {"CCEOC", ab8500_fg_cc_data_end_handler}, }; @@ -3194,21 +3197,36 @@ static int ab8500_fg_probe(struct platform_device *pdev) init_completion(&di->ab8500_fg_started); init_completion(&di->ab8500_fg_complete); - /* Register interrupts */ - for (i = 0; i < ARRAY_SIZE(ab8500_fg_irq); i++) { - irq = platform_get_irq_byname(pdev, ab8500_fg_irq[i].name); - ret = request_threaded_irq(irq, NULL, ab8500_fg_irq[i].isr, - IRQF_SHARED | IRQF_NO_SUSPEND, - ab8500_fg_irq[i].name, di); + /* Register primary interrupt handlers */ + for (i = 0; i < ARRAY_SIZE(ab8500_fg_irq_th); i++) { + irq = platform_get_irq_byname(pdev, ab8500_fg_irq_th[i].name); + ret = request_irq(irq, ab8500_fg_irq_th[i].isr, + IRQF_SHARED | IRQF_NO_SUSPEND, + ab8500_fg_irq_th[i].name, di); if (ret != 0) { - dev_err(di->dev, "failed to request %s IRQ %d: %d\n" - , ab8500_fg_irq[i].name, irq, ret); + dev_err(di->dev, "failed to request %s IRQ %d: %d\n", + ab8500_fg_irq_th[i].name, irq, ret); goto free_irq; } dev_dbg(di->dev, "Requested %s IRQ %d: %d\n", - ab8500_fg_irq[i].name, irq, ret); + ab8500_fg_irq_th[i].name, irq, ret); } + + /* Register threaded interrupt handler */ + irq = platform_get_irq_byname(pdev, ab8500_fg_irq_bh[0].name); + ret = request_threaded_irq(irq, NULL, ab8500_fg_irq_bh[0].isr, + IRQF_SHARED | IRQF_NO_SUSPEND | IRQF_ONESHOT, + ab8500_fg_irq_bh[0].name, di); + + if (ret != 0) { + dev_err(di->dev, "failed to request %s IRQ %d: %d\n", + ab8500_fg_irq_bh[0].name, irq, ret); + goto free_irq; + } + dev_dbg(di->dev, "Requested %s IRQ %d: %d\n", + ab8500_fg_irq_bh[0].name, irq, ret); + di->irq = platform_get_irq_byname(pdev, "CCEOC"); disable_irq(di->irq); di->nbr_cceoc_irq_cnt = 0; @@ -3245,11 +3263,13 @@ static int ab8500_fg_probe(struct platform_device *pdev) free_irq: power_supply_unregister(&di->fg_psy); - /* We also have to free all successfully registered irqs */ - for (i = i - 1; i >= 0; i--) { - irq = platform_get_irq_byname(pdev, ab8500_fg_irq[i].name); + /* We also have to free all registered irqs */ + for (i = 0; i < ARRAY_SIZE(ab8500_fg_irq_th); i++) { + irq = platform_get_irq_byname(pdev, ab8500_fg_irq_th[i].name); free_irq(irq, di); } + irq = platform_get_irq_byname(pdev, ab8500_fg_irq_bh[0].name); + free_irq(irq, di); free_inst_curr_wq: destroy_workqueue(di->fg_wq); return ret; -- 2.1.0 -- 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/
