On Monday, June 08, 2015 06:25:26 PM Viresh Kumar wrote:
Hi Rafael,
The aim of this series is to stop managing cpufreq sysfs directories on CPU hotplug.
Currently on removal of a 'cpu != policy->cpu', we remove its sysfs directories by removing the soft-link. And on removal of policy->cpu, we migrate the sysfs directories to the next cpu in policy. But if policy->cpu was the last CPU, we remove the policy completely and allocate it again once the CPUs come back.
This has shortcomings:
- Code Complexity
- Slower hotplug
- sysfs file permissions are reset after all policy->cpus are offlined
- CPUFreq stats history lost after all policy->cpus are offlined
- Special management of sysfs stuff during suspend/resume
To make things simple we can stop playing with sysfs files unless the driver is getting removed. Also the policy can be kept intact to be used later.
First few patches provide a clean base for others *more important* patches.
V6->V7:
- Change the order of patches, "cpufreq: Remove cpufreq_update_policy" is moved to the end of the series and updated its changelog.
V5-V6:
- Merged v4 9/14 into 10/14 after some updates.
- Keep separate routines to add/remove symlinks.
- Only updated one patch in this version
V4-V5:
- Sending all patches again
- Fixed comments in one of the patches as suggested by you
- Merged the last commit about "physical hotplug of CPUs" with "cpufreq: Stop migrating sysfs files on hotplug".
- A new patch (content is old, just separated out into its own patch) "cpufreq: add/remove sysfs links via cpufreq_add_remove_dev_symlink()"
V3-V4:
- Only four patches sent this time:
- [PATCH V4 01/14] cpufreq: Create for_each_{in}active_policy()
- [PATCH V4 04/14] cpufreq: Don't traverse all active policies to find
- [PATCH V4 05/14] cpufreq: Manage governor usage history with
- [PATCH V4 06/14] cpufreq: Mark policy->governor = NULL for inactive
- Remove __temp from the arguments of for_each_[in]active_policies.
- Simplified macros/next_policy, etc.
V2->V3:
- First five are already applied by you and the 7th one was sent separately as a fix earlier and got applied. So, V2 had 20 patches and V3 has 14.
- Dropped while(1) and used do/while.
- policy->governor marked as NULL only while removing the governor and not when policy becomes inactive.
- Commit logs/comments updated
- Applied Acks from Saravan
v1->V2:
- Dropped the idea of using policy-lists for getting policy for any cpu
- Also dropped fallback list and its per-cpu variable
- Stopped cleaning cpufreq_cpu_data and doing list_del(policy) on logical hotplug.
- Added support for physical hotplug of CPUs (Untested).
Viresh Kumar (6): cpufreq: Don't allow updating inactive policies from sysfs cpufreq: Stop migrating sysfs files on hotplug cpufreq: Initialize policy->kobj while allocating policy cpufreq: Call cpufreq_policy_put_kobj() from cpufreq_policy_free() cpufreq: Restart governor as soon as possible cpufreq: Remove cpufreq_update_policy()
drivers/cpufreq/cpufreq.c | 303 +++++++++++++++++++++++++--------------------- 1 file changed, 168 insertions(+), 135 deletions(-)
Overall, this looks good to me. There are some nitpicks here and there, though (please see replies to individual patches for details).