Hi Linus, James might still be in the process of sending this your way. However, given the proximity to -rc1, my reasoning for sending this directly is:
1/ It provides a tangible speed up for a non-esoteric use case (laptop resume): https://01.org/suspendresume/blogs/tebrandt/2013/hard-disk-resume-optimization-simpler-approach 2/ You already pulled the first half of this enabling from Tejun. Quoting Tejun's ATA pull request: "Dan finishes the patchset to make libata PM operations asynchronous. Combined with one patch being routed through scsi, this should speed resume measurably." 3/ As far as I can tell it is acceptable to James: http://marc.info/?l=linux-scsi&m=139499409510791&w=2 http://marc.info/?l=linux-scsi&m=139508044602605&w=2 http://marc.info/?l=linux-scsi&m=139536062515216&w=2 4/ I promised Todd I would get it upstream before he returns from vacation. Please pull, thank you. -- Dan The following changes since commit 455c6fdbd219161bd09b1165f11699d6d73de11c: Linux 3.14 (2014-03-30 20:40:15 -0700) are available in the git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/djbw/isci async-scsi-resume for you to fetch changes up to 3c31b52f96f7b559d950b16113c0f68c72a1985e: scsi: async sd resume (2014-04-10 15:30:35 -0700) ---------------------------------------------------------------- Dan Williams (1): scsi: async sd resume drivers/scsi/Kconfig | 3 ++ drivers/scsi/scsi.c | 9 ++++ drivers/scsi/scsi_pm.c | 128 ++++++++++++++++++++++++++++++++++++----------- drivers/scsi/scsi_priv.h | 2 + drivers/scsi/scsi_scan.c | 2 +- drivers/scsi/sd.c | 1 + 6 files changed, 115 insertions(+), 30 deletions(-) 8<------------- >From 3c31b52f96f7b559d950b16113c0f68c72a1985e Mon Sep 17 00:00:00 2001 From: Dan Williams <dan.j.willi...@intel.com> Date: Thu, 10 Apr 2014 15:30:35 -0700 Subject: [PATCH] scsi: async sd resume async_schedule() sd resume work to allow disks and other devices to resume in parallel. This moves the entirety of scsi_device resume to an async context to ensure that scsi_device_resume() remains ordered with respect to the completion of the start/stop command. For the duration of the resume, new command submissions (that do not originate from the scsi-core) will be deferred (BLKPREP_DEFER). It adds a new ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain) as a container of these operations. Like scsi_sd_probe_domain it is flushed at sd_remove() time to ensure async ops do not continue past the end-of-life of the sdev. The implementation explicitly refrains from reusing scsi_sd_probe_domain directly for this purpose as it is flushed at the end of dpm_resume(), potentially defeating some of the benefit. Given sdevs are quiesced it is permissible for these resume operations to bleed past the async_synchronize_full() calls made by the driver core. We defer the resolution of which pm callback to call until scsi_dev_type_{suspend|resume} time and guarantee that the callback parameter is never NULL. With this in place the type of resume operation is encoded in the async function identifier. There is a concern that async resume could trigger PSU overload. In the enterprise, storage enclosures enforce staggered spin-up regardless of what the kernel does making async scanning safe by default. Outside of that context a user can disable asynchronous scanning via a kernel command line or CONFIG_SCSI_SCAN_ASYNC. Honor that setting when deciding whether to do resume asynchronously. Inspired by Todd's analysis and initial proposal [2]: https://01.org/suspendresume/blogs/tebrandt/2013/hard-disk-resume-optimization-simpler-approach Cc: Len Brown <len.br...@intel.com> Cc: Phillip Susi <ps...@ubuntu.com> [alan: bug fix and clean up suggestion] Acked-by: Alan Stern <st...@rowland.harvard.edu> Suggested-by: Todd Brandt <todd.e.bra...@linux.intel.com> [djbw: kick all resume work to the async queue] Signed-off-by: Dan Williams <dan.j.willi...@intel.com> --- drivers/scsi/Kconfig | 3 ++ drivers/scsi/scsi.c | 9 ++++ drivers/scsi/scsi_pm.c | 128 ++++++++++++++++++++++++++++++++++++----------- drivers/scsi/scsi_priv.h | 2 + drivers/scsi/scsi_scan.c | 2 +- drivers/scsi/sd.c | 1 + 6 files changed, 115 insertions(+), 30 deletions(-) diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig index c8bd092..02832d6 100644 --- a/drivers/scsi/Kconfig +++ b/drivers/scsi/Kconfig @@ -263,6 +263,9 @@ config SCSI_SCAN_ASYNC You can override this choice by specifying "scsi_mod.scan=sync" or async on the kernel's command line. + Note that this setting also affects whether resuming from + system suspend will be performed asynchronously. + menu "SCSI Transports" depends on SCSI diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index d8afec8..1b345bf 100644 --- a/drivers/scsi/scsi.c +++ b/drivers/scsi/scsi.c @@ -91,6 +91,15 @@ EXPORT_SYMBOL(scsi_logging_level); ASYNC_DOMAIN(scsi_sd_probe_domain); EXPORT_SYMBOL(scsi_sd_probe_domain); +/* + * Separate domain (from scsi_sd_probe_domain) to maximize the benefit of + * asynchronous system resume operations. It is marked 'exclusive' to avoid + * being included in the async_synchronize_full() that is invoked by + * dpm_resume() + */ +ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain); +EXPORT_SYMBOL(scsi_sd_pm_domain); + /* NB: These are exposed through /proc/scsi/scsi and form part of the ABI. * You may not alter any existing entry (although adding new ones is * encouraged once assigned by ANSI/INCITS T10 diff --git a/drivers/scsi/scsi_pm.c b/drivers/scsi/scsi_pm.c index 001e9ce..7454498 100644 --- a/drivers/scsi/scsi_pm.c +++ b/drivers/scsi/scsi_pm.c @@ -18,35 +18,77 @@ #ifdef CONFIG_PM_SLEEP -static int scsi_dev_type_suspend(struct device *dev, int (*cb)(struct device *)) +static int do_scsi_suspend(struct device *dev, const struct dev_pm_ops *pm) { + return pm && pm->suspend ? pm->suspend(dev) : 0; +} + +static int do_scsi_freeze(struct device *dev, const struct dev_pm_ops *pm) +{ + return pm && pm->freeze ? pm->freeze(dev) : 0; +} + +static int do_scsi_poweroff(struct device *dev, const struct dev_pm_ops *pm) +{ + return pm && pm->poweroff ? pm->poweroff(dev) : 0; +} + +static int do_scsi_resume(struct device *dev, const struct dev_pm_ops *pm) +{ + return pm && pm->resume ? pm->resume(dev) : 0; +} + +static int do_scsi_thaw(struct device *dev, const struct dev_pm_ops *pm) +{ + return pm && pm->thaw ? pm->thaw(dev) : 0; +} + +static int do_scsi_restore(struct device *dev, const struct dev_pm_ops *pm) +{ + return pm && pm->restore ? pm->restore(dev) : 0; +} + +static int scsi_dev_type_suspend(struct device *dev, + int (*cb)(struct device *, const struct dev_pm_ops *)) +{ + const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; int err; + /* flush pending in-flight resume operations, suspend is synchronous */ + async_synchronize_full_domain(&scsi_sd_pm_domain); + err = scsi_device_quiesce(to_scsi_device(dev)); if (err == 0) { - if (cb) { - err = cb(dev); - if (err) - scsi_device_resume(to_scsi_device(dev)); - } + err = cb(dev, pm); + if (err) + scsi_device_resume(to_scsi_device(dev)); } dev_dbg(dev, "scsi suspend: %d\n", err); return err; } -static int scsi_dev_type_resume(struct device *dev, int (*cb)(struct device *)) +static int scsi_dev_type_resume(struct device *dev, + int (*cb)(struct device *, const struct dev_pm_ops *)) { + const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; int err = 0; - if (cb) - err = cb(dev); + err = cb(dev, pm); scsi_device_resume(to_scsi_device(dev)); dev_dbg(dev, "scsi resume: %d\n", err); + + if (err == 0) { + pm_runtime_disable(dev); + pm_runtime_set_active(dev); + pm_runtime_enable(dev); + } + return err; } static int -scsi_bus_suspend_common(struct device *dev, int (*cb)(struct device *)) +scsi_bus_suspend_common(struct device *dev, + int (*cb)(struct device *, const struct dev_pm_ops *)) { int err = 0; @@ -66,20 +108,54 @@ scsi_bus_suspend_common(struct device *dev, int (*cb)(struct device *)) return err; } -static int -scsi_bus_resume_common(struct device *dev, int (*cb)(struct device *)) +static void async_sdev_resume(void *dev, async_cookie_t cookie) { - int err = 0; + scsi_dev_type_resume(dev, do_scsi_resume); +} - if (scsi_is_sdev_device(dev)) - err = scsi_dev_type_resume(dev, cb); +static void async_sdev_thaw(void *dev, async_cookie_t cookie) +{ + scsi_dev_type_resume(dev, do_scsi_thaw); +} - if (err == 0) { +static void async_sdev_restore(void *dev, async_cookie_t cookie) +{ + scsi_dev_type_resume(dev, do_scsi_restore); +} + +static int scsi_bus_resume_common(struct device *dev, + int (*cb)(struct device *, const struct dev_pm_ops *)) +{ + async_func_t fn; + + if (!scsi_is_sdev_device(dev)) + fn = NULL; + else if (cb == do_scsi_resume) + fn = async_sdev_resume; + else if (cb == do_scsi_thaw) + fn = async_sdev_thaw; + else if (cb == do_scsi_restore) + fn = async_sdev_restore; + else + fn = NULL; + + if (fn) { + async_schedule_domain(fn, dev, &scsi_sd_pm_domain); + + /* + * If a user has disabled async probing a likely reason + * is due to a storage enclosure that does not inject + * staggered spin-ups. For safety, make resume + * synchronous as well in that case. + */ + if (strncmp(scsi_scan_type, "async", 5) != 0) + async_synchronize_full_domain(&scsi_sd_pm_domain); + } else { pm_runtime_disable(dev); pm_runtime_set_active(dev); pm_runtime_enable(dev); } - return err; + return 0; } static int scsi_bus_prepare(struct device *dev) @@ -97,38 +173,32 @@ static int scsi_bus_prepare(struct device *dev) static int scsi_bus_suspend(struct device *dev) { - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; - return scsi_bus_suspend_common(dev, pm ? pm->suspend : NULL); + return scsi_bus_suspend_common(dev, do_scsi_suspend); } static int scsi_bus_resume(struct device *dev) { - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; - return scsi_bus_resume_common(dev, pm ? pm->resume : NULL); + return scsi_bus_resume_common(dev, do_scsi_resume); } static int scsi_bus_freeze(struct device *dev) { - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; - return scsi_bus_suspend_common(dev, pm ? pm->freeze : NULL); + return scsi_bus_suspend_common(dev, do_scsi_freeze); } static int scsi_bus_thaw(struct device *dev) { - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; - return scsi_bus_resume_common(dev, pm ? pm->thaw : NULL); + return scsi_bus_resume_common(dev, do_scsi_thaw); } static int scsi_bus_poweroff(struct device *dev) { - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; - return scsi_bus_suspend_common(dev, pm ? pm->poweroff : NULL); + return scsi_bus_suspend_common(dev, do_scsi_poweroff); } static int scsi_bus_restore(struct device *dev) { - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; - return scsi_bus_resume_common(dev, pm ? pm->restore : NULL); + return scsi_bus_resume_common(dev, do_scsi_restore); } #else /* CONFIG_PM_SLEEP */ diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h index f079a59..48e5b65 100644 --- a/drivers/scsi/scsi_priv.h +++ b/drivers/scsi/scsi_priv.h @@ -112,6 +112,7 @@ extern void scsi_exit_procfs(void); #endif /* CONFIG_PROC_FS */ /* scsi_scan.c */ +extern char scsi_scan_type[]; extern int scsi_complete_async_scans(void); extern int scsi_scan_host_selected(struct Scsi_Host *, unsigned int, unsigned int, unsigned int, int); @@ -166,6 +167,7 @@ static inline int scsi_autopm_get_host(struct Scsi_Host *h) { return 0; } static inline void scsi_autopm_put_host(struct Scsi_Host *h) {} #endif /* CONFIG_PM_RUNTIME */ +extern struct async_domain scsi_sd_pm_domain; extern struct async_domain scsi_sd_probe_domain; /* diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c index 307a811..6b2f51f 100644 --- a/drivers/scsi/scsi_scan.c +++ b/drivers/scsi/scsi_scan.c @@ -97,7 +97,7 @@ MODULE_PARM_DESC(max_luns, #define SCSI_SCAN_TYPE_DEFAULT "sync" #endif -static char scsi_scan_type[6] = SCSI_SCAN_TYPE_DEFAULT; +char scsi_scan_type[6] = SCSI_SCAN_TYPE_DEFAULT; module_param_string(scan, scsi_scan_type, sizeof(scsi_scan_type), S_IRUGO); MODULE_PARM_DESC(scan, "sync, async or none"); diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 470954a..700c595 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -3020,6 +3020,7 @@ static int sd_remove(struct device *dev) devt = disk_devt(sdkp->disk); scsi_autopm_get_device(sdkp->device); + async_synchronize_full_domain(&scsi_sd_pm_domain); async_synchronize_full_domain(&scsi_sd_probe_domain); blk_queue_prep_rq(sdkp->device->request_queue, scsi_prep_fn); blk_queue_unprep_rq(sdkp->device->request_queue, NULL); -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
