My intention is to make it easier to manipulate kthreads. This RFC tries to use the kthread worker API. It is based on comments from the first attempt. See https://lkml.org/lkml/2015/7/28/648 and the list of changes below. 1st..8th patches: improve the existing kthread worker API 9th, 12th, 17th patches: convert three kthreads into the new API, namely: khugepaged, ring buffer benchmark, RCU gp kthreads[*] 10th, 11th patches: fix potential problems in the ring buffer benchmark; also sent separately 13th patch: small fix for RCU kthread; also sent separately; being tested by Paul 14th..16th patches: preparation steps for the RCU threads conversion; they are needed _only_ if we split GP start and QS handling into separate works[*] 18th patch: does a possible improvement of the kthread worker API; it adds an extra parameter to the create*() functions, so I rather put it into this draft [*] IMPORTANT: I tried to split RCU GP start and GS state handling into separate works this time. But there is a problem with a race in rcu_gp_kthread_worker_poke(). It might queue the wrong work. It can be detected and fixed by the work itself but it is a bit ugly. Alternative solution is to do both operations in one work. But then we sleep too much in the work which is ugly as well. Any idea is appreciated. Changes against v1: + remove wrappers to manipulate the scheduling policy and priority + remove questionable wakeup_and_destroy_kthread_worker() variant + do not check for chained work when draining the queue + allocate struct kthread worker in create_kthread_work() and use more simple checks for running worker + add support for delayed kthread works and use them instead of waiting inside the works + rework the "unrelated" fixes for the ring buffer benchmark as discussed in the 1st RFC; also sent separately + convert also the consumer in the ring buffer benchmark I have tested this patch set against the stable Linus tree for 4.3-rc2. Petr Mladek (18): kthread: Allow to call __kthread_create_on_node() with va_list args kthread: Add create_kthread_worker*() kthread: Add drain_kthread_worker() kthread: Add destroy_kthread_worker() kthread: Add pending flag to kthread work kthread: Initial support for delayed kthread work kthread: Allow to cancel kthread work kthread: Allow to modify delayed kthread work mm/huge_page: Convert khugepaged() into kthread worker API ring_buffer: Do no not complete benchmark reader too early ring_buffer: Fix more races when terminating the producer in the benchmark ring_buffer: Convert benchmark kthreads into kthread worker API rcu: Finish folding ->fqs_state into ->gp_state rcu: Store first_gp_fqs into struct rcu_state rcu: Clean up timeouts for forcing the quiescent state rcu: Check actual RCU_GP_FLAG_FQS when handling quiescent state rcu: Convert RCU gp kthreads into kthread worker API kthread: Better support freezable kthread workers include/linux/kthread.h | 67 +++++ kernel/kthread.c | 544 ++++++++++++++++++++++++++++++++--- kernel/rcu/tree.c | 407 ++++++++++++++++---------- kernel/rcu/tree.h | 24 +- kernel/rcu/tree_plugin.h | 16 +- kernel/rcu/tree_trace.c | 2 +- kernel/trace/ring_buffer_benchmark.c | 194 ++++++------- mm/huge_memory.c | 116 ++++---- 8 files changed, 1017 insertions(+), 353 deletions(-) -- 1.8.5.6 -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
