user/sven/linux.git/kernel/sched/rt.c, branch v5.9.8

sched: Remove struct sched_class::next field

2020-06-25T11:45:44Z

Now that the sched_class descriptors are defined in order via the linker script vmlinux.lds.h, there's no reason to have a "next" pointer to the previous priroity structure. The order of the sturctures can be aligned as an array, and used to index and find the next sched_class descriptor. Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20191219214558.845353593@goodmis.org

sched: Force the address order of each sched class descriptor

2020-06-25T11:45:43Z

In order to make a micro optimization in pick_next_task(), the order of the sched class descriptor address must be in the same order as their priority to each other. That is: &idle_sched_class < &fair_sched_class < &rt_sched_class < &dl_sched_class < &stop_sched_class In order to guarantee this order of the sched class descriptors, add each one into their own data section and force the order in the linker script. Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/157675913272.349305.8936736338884044103.stgit@localhost.localdomain

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

2020-06-03T23:27:18Z

Pull networking updates from David Miller: 1) Allow setting bluetooth L2CAP modes via socket option, from Luiz Augusto von Dentz. 2) Add GSO partial support to igc, from Sasha Neftin. 3) Several cleanups and improvements to r8169 from Heiner Kallweit. 4) Add IF_OPER_TESTING link state and use it when ethtool triggers a device self-test. From Andrew Lunn. 5) Start moving away from custom driver versions, use the globally defined kernel version instead, from Leon Romanovsky. 6) Support GRO vis gro_cells in DSA layer, from Alexander Lobakin. 7) Allow hard IRQ deferral during NAPI, from Eric Dumazet. 8) Add sriov and vf support to hinic, from Luo bin. 9) Support Media Redundancy Protocol (MRP) in the bridging code, from Horatiu Vultur. 10) Support netmap in the nft_nat code, from Pablo Neira Ayuso. 11) Allow UDPv6 encapsulation of ESP in the ipsec code, from Sabrina Dubroca. Also add ipv6 support for espintcp. 12) Lots of ReST conversions of the networking documentation, from Mauro Carvalho Chehab. 13) Support configuration of ethtool rxnfc flows in bcmgenet driver, from Doug Berger. 14) Allow to dump cgroup id and filter by it in inet_diag code, from Dmitry Yakunin. 15) Add infrastructure to export netlink attribute policies to userspace, from Johannes Berg. 16) Several optimizations to sch_fq scheduler, from Eric Dumazet. 17) Fallback to the default qdisc if qdisc init fails because otherwise a packet scheduler init failure will make a device inoperative. From Jesper Dangaard Brouer. 18) Several RISCV bpf jit optimizations, from Luke Nelson. 19) Correct the return type of the ->ndo_start_xmit() method in several drivers, it's netdev_tx_t but many drivers were using 'int'. From Yunjian Wang. 20) Add an ethtool interface for PHY master/slave config, from Oleksij Rempel. 21) Add BPF iterators, from Yonghang Song. 22) Add cable test infrastructure, including ethool interfaces, from Andrew Lunn. Marvell PHY driver is the first to support this facility. 23) Remove zero-length arrays all over, from Gustavo A. R. Silva. 24) Calculate and maintain an explicit frame size in XDP, from Jesper Dangaard Brouer. 25) Add CAP_BPF, from Alexei Starovoitov. 26) Support terse dumps in the packet scheduler, from Vlad Buslov. 27) Support XDP_TX bulking in dpaa2 driver, from Ioana Ciornei. 28) Add devm_register_netdev(), from Bartosz Golaszewski. 29) Minimize qdisc resets, from Cong Wang. 30) Get rid of kernel_getsockopt and kernel_setsockopt in order to eliminate set_fs/get_fs calls. From Christoph Hellwig. * git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2517 commits) selftests: net: ip_defrag: ignore EPERM net_failover: fixed rollback in net_failover_open() Revert "tipc: Fix potential tipc_aead refcnt leak in tipc_crypto_rcv" Revert "tipc: Fix potential tipc_node refcnt leak in tipc_rcv" vmxnet3: allow rx flow hash ops only when rss is enabled hinic: add set_channels ethtool_ops support selftests/bpf: Add a default $(CXX) value tools/bpf: Don't use $(COMPILE.c) bpf, selftests: Use bpf_probe_read_kernel s390/bpf: Use bcr 0,%0 as tail call nop filler s390/bpf: Maintain 8-byte stack alignment selftests/bpf: Fix verifier test selftests/bpf: Fix sample_cnt shared between two threads bpf, selftests: Adapt cls_redirect to call csum_level helper bpf: Add csum_level helper for fixing up csum levels bpf: Fix up bpf_skb_adjust_room helper's skb csum setting sfc: add missing annotation for efx_ef10_try_update_nic_stats_vf() crypto/chtls: IPv6 support for inline TLS Crypto/chcr: Fixes a coccinile check error Crypto/chcr: Fixes compilations warnings ...

sched: Defend cfs and rt bandwidth quota against overflow

2020-05-19T18:34:14Z

When users write some huge number into cpu.cfs_quota_us or cpu.rt_runtime_us, overflow might happen during to_ratio() shifts of schedulable checks. to_ratio() could be altered to avoid unnecessary internal overflow, but min_cfs_quota_period is less than 1 << BW_SHIFT, so a cutoff would still be needed. Set a cap MAX_BW for cfs_quota_us and rt_runtime_us to prevent overflow. Signed-off-by: Huaixin Chang Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Ben Segall Link: https://lkml.kernel.org/r/20200425105248.60093-1-changhuaixin@linux.alibaba.com

sysctl: pass kernel pointers to ->proc_handler

2020-04-27T06:07:40Z

Instead of having all the sysctl handlers deal with user pointers, which is rather hairy in terms of the BPF interaction, copy the input to and from userspace in common code. This also means that the strings are always NUL-terminated by the common code, making the API a little bit safer. As most handler just pass through the data to one of the common handlers a lot of the changes are mechnical. Signed-off-by: Christoph Hellwig Acked-by: Andrey Ignatov Signed-off-by: Al Viro

sched/rt: Remove unnecessary push for unfit tasks

2020-03-06T11:57:29Z

In task_woken_rt() and switched_to_rto() we try trigger push-pull if the task is unfit. But the logic is found lacking because if the task was the only one running on the CPU, then rt_rq is not in overloaded state and won't trigger a push. The necessity of this logic was under a debate as well, a summary of the discussion can be found in the following thread: https://lore.kernel.org/lkml/20200226160247.iqvdakiqbakk2llz@e107158-lin.cambridge.arm.com/ Remove the logic for now until a better approach is agreed upon. Signed-off-by: Qais Yousef Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Fixes: 804d402fb6f6 ("sched/rt: Make RT capacity-aware") Link: https://lkml.kernel.org/r/20200302132721.8353-6-qais.yousef@arm.com

sched/rt: Allow pulling unfitting task

2020-03-06T11:57:28Z

When implemented RT Capacity Awareness; the logic was done such that if a task was running on a fitting CPU, then it was sticky and we would try our best to keep it there. But as Steve suggested, to adhere to the strict priority rules of RT class; allow pulling an RT task to unfitting CPU to ensure it gets a chance to run ASAP. LINK: https://lore.kernel.org/lkml/20200203111451.0d1da58f@oasis.local.home/ Suggested-by: Steven Rostedt Signed-off-by: Qais Yousef Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Fixes: 804d402fb6f6 ("sched/rt: Make RT capacity-aware") Link: https://lkml.kernel.org/r/20200302132721.8353-5-qais.yousef@arm.com

sched/rt: Optimize cpupri_find() on non-heterogenous systems

2020-03-06T11:57:27Z

By introducing a new cpupri_find_fitness() function that takes the fitness_fn as an argument and only called when asym_system static key is enabled. cpupri_find() is now a wrapper function that calls cpupri_find_fitness() passing NULL as a fitness_fn, hence disabling the logic that handles fitness by default. LINK: https://lore.kernel.org/lkml/c0772fca-0a4b-c88d-fdf2-5715fcf8447b@arm.com/ Reported-by: Dietmar Eggemann Signed-off-by: Qais Yousef Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Fixes: 804d402fb6f6 ("sched/rt: Make RT capacity-aware") Link: https://lkml.kernel.org/r/20200302132721.8353-4-qais.yousef@arm.com

sched/rt: Re-instate old behavior in select_task_rq_rt()

2020-03-06T11:57:27Z

When RT Capacity Aware support was added, the logic in select_task_rq_rt was modified to force a search for a fitting CPU if the task currently doesn't run on one. But if the search failed, and the search was only triggered to fulfill the fitness request; we could end up selecting a new CPU unnecessarily. Fix this and re-instate the original behavior by ensuring we bail out in that case. This behavior change only affected asymmetric systems that are using util_clamp to implement capacity aware. None asymmetric systems weren't affected. LINK: https://lore.kernel.org/lkml/20200218041620.GD28029@codeaurora.org/ Reported-by: Pavan Kondeti Signed-off-by: Qais Yousef Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Fixes: 804d402fb6f6 ("sched/rt: Make RT capacity-aware") Link: https://lkml.kernel.org/r/20200302132721.8353-3-qais.yousef@arm.com

sched/rt: Optimize checking group RT scheduler constraints

2020-01-28T20:37:09Z

Group RT scheduler contains protection against setting zero runtime for cgroup with RT tasks. Right now function tg_set_rt_bandwidth() iterates over all CPU cgroups and calls tg_has_rt_tasks() for any cgroup which runtime is zero (not only for changed one). Default RT runtime is zero, thus tg_has_rt_tasks() will is called for almost at CPU cgroups. This protection already is slightly racy: runtime limit could be changed between cpu_cgroup_can_attach() and cpu_cgroup_attach() because changing cgroup attribute does not lock cgroup_mutex while attach does not lock rt_constraints_mutex. Changing task scheduler class also races with changing rt runtime: check in __sched_setscheduler() isn't protected. Function tg_has_rt_tasks() iterates over all threads in the system. This gives NR_CGROUPS * NR_TASKS operations under single tasklist_lock locked for read tg_set_rt_bandwidth(). Any concurrent attempt of locking tasklist_lock for write (for example fork) will stuck with disabled irqs. This patch makes two optimizations: 1) Remove locking tasklist_lock and iterate only tasks in cgroup 2) Call tg_has_rt_tasks() iff rt runtime changes from non-zero to zero All changed code is under CONFIG_RT_GROUP_SCHED. Testcase: # mkdir /sys/fs/cgroup/cpu/test{1..10000} # echo 0 | tee /sys/fs/cgroup/cpu/test*/cpu.rt_runtime_us At the same time without patch fork time will be >100ms: # perf trace -e clone --duration 100 stress-ng --fork 1 Also remote ping will show timings >100ms caused by irq latency. Signed-off-by: Konstantin Khlebnikov Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Link: https://lkml.kernel.org/r/157996383820.4651.11292439232549211693.stgit@buzz