Messages in this thread | | | Date | Wed, 29 Mar 2023 10:34:57 -0400 | Subject | Re: [PATCH 0/6] sched/deadline: cpuset: Rework DEADLINE bandwidth restoration | From | Waiman Long <> |
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On 3/29/23 08:55, Juri Lelli wrote: > Qais reported [1] that iterating over all tasks when rebuilding root > domains for finding out which ones are DEADLINE and need their bandwidth > correctly restored on such root domains can be a costly operation (10+ > ms delays on suspend-resume). He proposed we skip rebuilding root > domains for certain operations, but that approach seemed arch specific > and possibly prone to errors, as paths that ultimately trigger a rebuild > might be quite convoluted (thanks Qais for spending time on this!). > > To fix the problem > > 01/06 - Rename functions deadline with DEADLINE accounting (cleanup > suggested by Qais) - no functional change > 02/06 - Bring back cpuset_mutex (so that we have write access to cpusets > from scheduler operations - and we also fix some problems > associated to percpu_cpuset_rwsem) > 03/06 - Keep track of the number of DEADLINE tasks belonging to each cpuset > 04/06 - Create DL BW alloc, free & check overflow interface for bulk > bandwidth allocation/removal - no functional change > 05/06 - Fix bandwidth allocation handling for cgroup operation > involving multiple tasks > 06/06 - Use this information to only perform the costly iteration if > DEADLINE tasks are actually present in the cpuset for which a > corresponding root domain is being rebuilt > > With respect to the RFC posting [2] > > 1 - rename DEADLINE bandwidth accounting functions - Qais > 2 - call inc/dec_dl_tasks_cs from switched_{to,from}_dl - Qais > 3 - fix DEADLINE bandwidth allocation with multiple tasks - Waiman, > contributed by Dietmar > > This set is also available from > > https://github.com/jlelli/linux.git deadline/rework-cpusets > > Best, > Juri > > 1 - https://lore.kernel.org/lkml/20230206221428.2125324-1-qyousef@layalina.io/ > 2 - https://lore.kernel.org/lkml/20230315121812.206079-1-juri.lelli@redhat.com/ > > Dietmar Eggemann (2): > sched/deadline: Create DL BW alloc, free & check overflow interface > cgroup/cpuset: Free DL BW in case can_attach() fails > > Juri Lelli (4): > cgroup/cpuset: Rename functions dealing with DEADLINE accounting > sched/cpuset: Bring back cpuset_mutex > sched/cpuset: Keep track of SCHED_DEADLINE task in cpusets > cgroup/cpuset: Iterate only if DEADLINE tasks are present > > include/linux/cpuset.h | 12 ++- > include/linux/sched.h | 4 +- > kernel/cgroup/cgroup.c | 4 + > kernel/cgroup/cpuset.c | 232 ++++++++++++++++++++++++++-------------- > kernel/sched/core.c | 41 ++++--- > kernel/sched/deadline.c | 67 +++++++++--- > kernel/sched/sched.h | 2 +- > 7 files changed, 240 insertions(+), 122 deletions(-)
Other than some minor issues that I have talked in earlier emails, the patch series looks good to me.
You can add my ack once the issues are fixed.
Acked-by: Waiman Long <longman@redhat.com>
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