From: Leonard Crestez <leonard.crestez@nxp.com> To: "Rafael J. Wysocki" <rjw@rjwysocki.net>, Chanwoo Choi <cw00.choi@samsung.com> Cc: "Matthias Kaehlcke" <mka@chromium.org>, "Kyungmin Park" <kyungmin.park@samsung.com>, "MyungJoo Ham" <myungjoo.ham@samsung.com>, "Artur Świgoń" <a.swigon@partner.samsung.com>, "Georgi Djakov" <georgi.djakov@linaro.org>, "Jacky Bai" <ping.bai@nxp.com>, "Viresh Kumar" <viresh.kumar@linaro.org>, "NXP Linux Team" <linux-imx@nxp.com>, linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH v2 0/2] PM / devfreq: Add dev_pm_qos support Date: Thu, 5 Dec 2019 12:05:05 +0200 [thread overview] Message-ID: <cover.1575540224.git.leonard.crestez@nxp.com> (raw) Add dev_pm_qos notifiers to devfreq core in order to support frequency limits via dev_pm_qos_add_request. Unlike the rest of devfreq the dev_pm_qos frequency is measured in kHz, this is consistent with current dev_pm_qos usage for cpufreq and allows frequencies above 2Ghz (pm_qos expresses limits as s32). Like with cpufreq the handling of min_freq/max_freq is moved to the dev_pm_qos mechanism. Constraints from userspace are no longer clamped on store, instead all values can be written and we only check against OPPs in a new devfreq_get_freq_range function. This is consistent with the design of dev_pm_qos. Notifiers from pm_qos are executed under a single global dev_pm_qos_mtx and need to take devfreq->lock, this means that calls into dev_pm_qos while holding devfreq->lock are not allowed (lockdep warns about possible deadlocks). Fix this by only adding the qos request and notifiers after devfreq->lock is released inside devfreq_add_device. In theory this means sysfs writes are possible before the min/max requests are initialized so we guard against that explictly. The dev_pm_qos_update_request function would otherwise print a big WARN splat. This series depends on recently accepted series restoring DEV_PM_QOS_MIN/MAX_FREQUENCY inside the pm core: https://patchwork.kernel.org/cover/11262633/ It would be great for this to get into 5.5-rc1 --- Changes since RFC v1: * Trim cover letter * Drop RFC since DEV_PM_QOS_MIN/MAX_FREQUENCY was restored * Collect Acks. * No code changes Link to v1: https://patchwork.kernel.org/cover/11252415/ Changes since "big version" v10: * Drop accepted cleanups * Work with current locking approach (split cleanups into other series) * Drop acks and deliberately relabel as a new series. It still incorporates most previous discussion but takes a different approach to locking. * Don't print errors if devfreq_dev_release is called on error cleanup from devfreq_add_device, just accept that requests and notifiers might not be registered yet. I wish dev_pm_qos cleanups behaved like standard "kfree" and silently did nothing when there's nothing to be done. Link to v10: https://patchwork.kernel.org/project/linux-arm-kernel/list/?series=196443 Leonard Crestez (2): PM / devfreq: Add PM QoS support PM / devfreq: Use PM QoS for sysfs min/max_freq drivers/devfreq/devfreq.c | 151 ++++++++++++++++++++++++++++++++++---- include/linux/devfreq.h | 14 +++- 2 files changed, 145 insertions(+), 20 deletions(-) -- 2.17.1
WARNING: multiple messages have this Message-ID (diff)
From: Leonard Crestez <leonard.crestez@nxp.com> To: "Rafael J. Wysocki" <rjw@rjwysocki.net>, Chanwoo Choi <cw00.choi@samsung.com> Cc: "Artur Świgoń" <a.swigon@partner.samsung.com>, "Jacky Bai" <ping.bai@nxp.com>, linux-pm@vger.kernel.org, "Viresh Kumar" <viresh.kumar@linaro.org>, "Kyungmin Park" <kyungmin.park@samsung.com>, "Matthias Kaehlcke" <mka@chromium.org>, "MyungJoo Ham" <myungjoo.ham@samsung.com>, "Georgi Djakov" <georgi.djakov@linaro.org>, linux-arm-kernel@lists.infradead.org, "NXP Linux Team" <linux-imx@nxp.com> Subject: [PATCH v2 0/2] PM / devfreq: Add dev_pm_qos support Date: Thu, 5 Dec 2019 12:05:05 +0200 [thread overview] Message-ID: <cover.1575540224.git.leonard.crestez@nxp.com> (raw) Add dev_pm_qos notifiers to devfreq core in order to support frequency limits via dev_pm_qos_add_request. Unlike the rest of devfreq the dev_pm_qos frequency is measured in kHz, this is consistent with current dev_pm_qos usage for cpufreq and allows frequencies above 2Ghz (pm_qos expresses limits as s32). Like with cpufreq the handling of min_freq/max_freq is moved to the dev_pm_qos mechanism. Constraints from userspace are no longer clamped on store, instead all values can be written and we only check against OPPs in a new devfreq_get_freq_range function. This is consistent with the design of dev_pm_qos. Notifiers from pm_qos are executed under a single global dev_pm_qos_mtx and need to take devfreq->lock, this means that calls into dev_pm_qos while holding devfreq->lock are not allowed (lockdep warns about possible deadlocks). Fix this by only adding the qos request and notifiers after devfreq->lock is released inside devfreq_add_device. In theory this means sysfs writes are possible before the min/max requests are initialized so we guard against that explictly. The dev_pm_qos_update_request function would otherwise print a big WARN splat. This series depends on recently accepted series restoring DEV_PM_QOS_MIN/MAX_FREQUENCY inside the pm core: https://patchwork.kernel.org/cover/11262633/ It would be great for this to get into 5.5-rc1 --- Changes since RFC v1: * Trim cover letter * Drop RFC since DEV_PM_QOS_MIN/MAX_FREQUENCY was restored * Collect Acks. * No code changes Link to v1: https://patchwork.kernel.org/cover/11252415/ Changes since "big version" v10: * Drop accepted cleanups * Work with current locking approach (split cleanups into other series) * Drop acks and deliberately relabel as a new series. It still incorporates most previous discussion but takes a different approach to locking. * Don't print errors if devfreq_dev_release is called on error cleanup from devfreq_add_device, just accept that requests and notifiers might not be registered yet. I wish dev_pm_qos cleanups behaved like standard "kfree" and silently did nothing when there's nothing to be done. Link to v10: https://patchwork.kernel.org/project/linux-arm-kernel/list/?series=196443 Leonard Crestez (2): PM / devfreq: Add PM QoS support PM / devfreq: Use PM QoS for sysfs min/max_freq drivers/devfreq/devfreq.c | 151 ++++++++++++++++++++++++++++++++++---- include/linux/devfreq.h | 14 +++- 2 files changed, 145 insertions(+), 20 deletions(-) -- 2.17.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply other threads:[~2019-12-05 10:05 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-12-05 10:05 Leonard Crestez [this message] 2019-12-05 10:05 ` [PATCH v2 0/2] PM / devfreq: Add dev_pm_qos support Leonard Crestez 2019-12-05 10:05 ` [PATCH v2 1/2] PM / devfreq: Add PM QoS support Leonard Crestez 2019-12-05 10:05 ` Leonard Crestez 2019-12-05 17:48 ` Matthias Kaehlcke 2019-12-05 17:48 ` Matthias Kaehlcke 2019-12-10 1:24 ` Leonard Crestez 2019-12-10 1:24 ` Leonard Crestez 2019-12-05 10:05 ` [PATCH v2 2/2] PM / devfreq: Use PM QoS for sysfs min/max_freq Leonard Crestez 2019-12-05 10:05 ` Leonard Crestez 2019-12-05 18:02 ` Matthias Kaehlcke 2019-12-05 18:02 ` Matthias Kaehlcke 2019-12-06 2:38 ` Chanwoo Choi 2019-12-06 2:38 ` Chanwoo Choi 2019-12-05 10:12 ` [PATCH v2 0/2] PM / devfreq: Add dev_pm_qos support Rafael J. Wysocki 2019-12-05 10:12 ` Rafael J. Wysocki 2019-12-05 10:44 ` Leonard Crestez 2019-12-05 10:44 ` Leonard Crestez 2019-12-06 3:27 ` Chanwoo Choi 2019-12-06 3:27 ` Chanwoo Choi 2019-12-06 4:54 ` Chanwoo Choi 2019-12-06 4:54 ` Chanwoo Choi
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