Hi Rafael, You can pretty much ignore this series until all other OPP cleanup/fixes get merged. I am posting these to get early reviews from Stephen as these patches have been lying with me for almost a week now. And I am also _not_ pushing these for 4.10-rc1. It all depends on how the reviews go.
The RCU locking isn't well suited for the OPP core. The RCU locking fits better for reader heavy stuff, while the OPP core have at max one or two readers only at a time. Over that, it was getting very confusing the way RCU locking was used within the OPP core. The individual OPPs are mostly well handled, i.e. for an update a new structure was created and then that replaced the older one. But the OPP tables were updated directly all the time from various parts of the core. Though they were mostly used from within RCU locked region, they didn't had much to do with RCU and were governed by the mutex instead. And that mixed with the 'opp_table_lock' has made the core even more confusing. Similar concerns were shared by Stephen Boyd earlier [1]. This patchset simplifies the locking in OPP core to great extent using Kernel reference counting mechanism along with per OPP table mutex. And finally it gets rid of RCU locking as well. Each and every patch of this series is individually: - build tested - boot tested with cpufreq-dt.ko module. Insmod and rmmod to make sure the OPPs and the OPP tables are getting freed. More testing is also done by various build and boot bots for last few days. And they reported lots of issues (both build and boot time) that helped making this series more robust: - Kernel CI (Linaro) - Fengguang Wu's bot (Intel) This series has few dependencies though. It is rebased over: pm/bleeding-edge + OPP cleanup series [2] + few devfreq fixes [3], [4], and [5]. + A recent revert [6] Though all of those shall get merged before we end up reviewing this series. -- viresh [1] https://marc.info/?l=linux-kernel&m=147742717527548&w=2 [2] https://marc.info/?l=linux-pm&m=148108573618896&w=2 [3] https://patchwork.kernel.org/patch/9455789/ [4] https://patchwork.kernel.org/patch/9455757/ [5] https://marc.info/?l=linux-pm&m=148090824301852&w=2 [6] https://marc.info/?l=linux-kernel&m=148110674223377&w=2 Viresh Kumar (12): PM / OPP: Add per OPP table mutex PM / OPP: Add 'struct kref' to OPP table PM / OPP: Return opp_table from dev_pm_opp_set_*() routines PM / OPP: Take reference of the OPP table while adding/removing OPPs PM / OPP: Use dev_pm_opp_get_opp_table() instead of _add_opp_table() PM / OPP: Add 'struct kref' to struct dev_pm_opp PM / OPP: Update OPP users to put reference PM / OPP: Take kref from _find_opp_table() PM / OPP: Move away from RCU locking PM / OPP: Simplify _opp_set_availability() PM / OPP: Simplify dev_pm_opp_get_max_volt_latency() PM / OPP: Update Documentation to remove RCU specific bits Documentation/power/opp.txt | 47 +- arch/arm/mach-omap2/pm.c | 5 +- drivers/base/power/opp/core.c | 888 +++++++++++------------------------ drivers/base/power/opp/cpu.c | 66 +-- drivers/base/power/opp/of.c | 94 +--- drivers/base/power/opp/opp.h | 31 +- drivers/clk/tegra/clk-dfll.c | 17 +- drivers/cpufreq/exynos5440-cpufreq.c | 5 +- drivers/cpufreq/imx6q-cpufreq.c | 10 +- drivers/cpufreq/mt8173-cpufreq.c | 8 +- drivers/cpufreq/omap-cpufreq.c | 4 +- drivers/cpufreq/sti-cpufreq.c | 13 +- drivers/devfreq/devfreq.c | 14 +- drivers/devfreq/exynos-bus.c | 14 +- drivers/devfreq/governor_passive.c | 4 +- drivers/devfreq/rk3399_dmc.c | 16 +- drivers/devfreq/tegra-devfreq.c | 4 +- drivers/thermal/cpu_cooling.c | 11 +- drivers/thermal/devfreq_cooling.c | 14 +- include/linux/pm_opp.h | 48 +- 20 files changed, 429 insertions(+), 884 deletions(-) -- 2.7.1.410.g6faf27b
