user/sven/linux.git/kernel/cgroup, branch v5.1.19

cpuset: restore sanity to cpuset_cpus_allowed_fallback()

2019-07-10T07:52:27Z

[ Upstream commit d477f8c202d1f0d4791ab1263ca7657bbe5cf79e ] In the case that a process is constrained by taskset(1) (i.e. sched_setaffinity(2)) to a subset of available cpus, and all of those are subsequently offlined, the scheduler will set tsk->cpus_allowed to the current value of task_cs(tsk)->effective_cpus. This is done via a call to do_set_cpus_allowed() in the context of cpuset_cpus_allowed_fallback() made by the scheduler when this case is detected. This is the only call made to cpuset_cpus_allowed_fallback() in the latest mainline kernel. However, this is not sane behavior. I will demonstrate this on a system running the latest upstream kernel with the following initial configuration: # grep -i cpu /proc/$$/status Cpus_allowed: ffffffff,fffffff Cpus_allowed_list: 0-63 (Where cpus 32-63 are provided via smt.) If we limit our current shell process to cpu2 only and then offline it and reonline it: # taskset -p 4 $$ pid 2272's current affinity mask: ffffffffffffffff pid 2272's new affinity mask: 4 # echo off > /sys/devices/system/cpu/cpu2/online # dmesg | tail -3 [ 2195.866089] process 2272 (bash) no longer affine to cpu2 [ 2195.872700] IRQ 114: no longer affine to CPU2 [ 2195.879128] smpboot: CPU 2 is now offline # echo on > /sys/devices/system/cpu/cpu2/online # dmesg | tail -1 [ 2617.043572] smpboot: Booting Node 0 Processor 2 APIC 0x4 We see that our current process now has an affinity mask containing every cpu available on the system _except_ the one we originally constrained it to: # grep -i cpu /proc/$$/status Cpus_allowed: ffffffff,fffffffb Cpus_allowed_list: 0-1,3-63 This is not sane behavior, as the scheduler can now not only place the process on previously forbidden cpus, it can't even schedule it on the cpu it was originally constrained to! Other cases result in even more exotic affinity masks. Take for instance a process with an affinity mask containing only cpus provided by smt at the moment that smt is toggled, in a configuration such as the following: # taskset -p f000000000 $$ # grep -i cpu /proc/$$/status Cpus_allowed: 000000f0,00000000 Cpus_allowed_list: 36-39 A double toggle of smt results in the following behavior: # echo off > /sys/devices/system/cpu/smt/control # echo on > /sys/devices/system/cpu/smt/control # grep -i cpus /proc/$$/status Cpus_allowed: ffffff00,ffffffff Cpus_allowed_list: 0-31,40-63 This is even less sane than the previous case, as the new affinity mask excludes all smt-provided cpus with ids less than those that were previously in the affinity mask, as well as those that were actually in the mask. With this patch applied, both of these cases end in the following state: # grep -i cpu /proc/$$/status Cpus_allowed: ffffffff,ffffffff Cpus_allowed_list: 0-63 The original policy is discarded. Though not ideal, it is the simplest way to restore sanity to this fallback case without reinventing the cpuset wheel that rolls down the kernel just fine in cgroup v2. A user who wishes for the previous affinity mask to be restored in this fallback case can use that mechanism instead. This patch modifies scheduler behavior by instead resetting the mask to task_cs(tsk)->cpus_allowed by default, and cpu_possible mask in legacy mode. I tested the cases above on both modes. Note that the scheduler uses this fallback mechanism if and only if _every_ other valid avenue has been traveled, and it is the last resort before calling BUG(). Suggested-by: Waiman Long Suggested-by: Phil Auld Signed-off-by: Joel Savitz Acked-by: Phil Auld Acked-by: Waiman Long Acked-by: Peter Zijlstra (Intel) Signed-off-by: Tejun Heo Signed-off-by: Sasha Levin

mm, memcg: consider subtrees in memory.events

2019-06-09T07:16:13Z

commit 9852ae3fe5293264f01c49f2571ef7688f7823ce upstream. memory.stat and other files already consider subtrees in their output, and we should too in order to not present an inconsistent interface. The current situation is fairly confusing, because people interacting with cgroups expect hierarchical behaviour in the vein of memory.stat, cgroup.events, and other files. For example, this causes confusion when debugging reclaim events under low, as currently these always read "0" at non-leaf memcg nodes, which frequently causes people to misdiagnose breach behaviour. The same confusion applies to other counters in this file when debugging issues. Aggregation is done at write time instead of at read-time since these counters aren't hot (unlike memory.stat which is per-page, so it does it at read time), and it makes sense to bundle this with the file notifications. After this patch, events are propagated up the hierarchy: [root@ktst ~]# cat /sys/fs/cgroup/system.slice/memory.events low 0 high 0 max 0 oom 0 oom_kill 0 [root@ktst ~]# systemd-run -p MemoryMax=1 true Running as unit: run-r251162a189fb4562b9dabfdc9b0422f5.service [root@ktst ~]# cat /sys/fs/cgroup/system.slice/memory.events low 0 high 0 max 7 oom 1 oom_kill 1 As this is a change in behaviour, this can be reverted to the old behaviour by mounting with the `memory_localevents' flag set. However, we use the new behaviour by default as there's a lack of evidence that there are any current users of memory.events that would find this change undesirable. akpm: this is a behaviour change, so Cc:stable. THis is so that forthcoming distros which use cgroup v2 are more likely to pick up the revised behaviour. Link: http://lkml.kernel.org/r/20190208224419.GA24772@chrisdown.name Signed-off-by: Chris Down Acked-by: Johannes Weiner Reviewed-by: Shakeel Butt Cc: Michal Hocko Cc: Tejun Heo Cc: Roman Gushchin Cc: Dennis Zhou Cc: Suren Baghdasaryan Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

cgroup: protect cgroup->nr_(dying_)descendants by css_set_lock

2019-05-31T13:43:29Z

[ Upstream commit 4dcabece4c3a9f9522127be12cc12cc120399b2f ] The number of descendant cgroups and the number of dying descendant cgroups are currently synchronized using the cgroup_mutex. The number of descendant cgroups will be required by the cgroup v2 freezer, which will use it to determine if a cgroup is frozen (depending on total number of descendants and number of frozen descendants). It's not always acceptable to grab the cgroup_mutex, especially from quite hot paths (e.g. exit()). To avoid this, let's additionally synchronize these counters using the css_set_lock. So, it's safe to read these counters with either cgroup_mutex or css_set_lock locked, and for changing both locks should be acquired. Signed-off-by: Roman Gushchin Signed-off-by: Tejun Heo Cc: kernel-team@fb.com Signed-off-by: Sasha Levin

Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2019-03-12T21:08:19Z

Pull vfs mount infrastructure updates from Al Viro: "The rest of core infrastructure; no new syscalls in that pile, but the old parts are switched to new infrastructure. At that point conversions of individual filesystems can happen independently; some are done here (afs, cgroup, procfs, etc.), there's also a large series outside of that pile dealing with NFS (quite a bit of option-parsing stuff is getting used there - it's one of the most convoluted filesystems in terms of mount-related logics), but NFS bits are the next cycle fodder. It got seriously simplified since the last cycle; documentation is probably the weakest bit at the moment - I considered dropping the commit introducing Documentation/filesystems/mount_api.txt (cutting the size increase by quarter ;-), but decided that it would be better to fix it up after -rc1 instead. That pile allows to do followup work in independent branches, which should make life much easier for the next cycle. fs/super.c size increase is unpleasant; there's a followup series that allows to shrink it considerably, but I decided to leave that until the next cycle" * 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (41 commits) afs: Use fs_context to pass parameters over automount afs: Add fs_context support vfs: Add some logging to the core users of the fs_context log vfs: Implement logging through fs_context vfs: Provide documentation for new mount API vfs: Remove kern_mount_data() hugetlbfs: Convert to fs_context cpuset: Use fs_context kernfs, sysfs, cgroup, intel_rdt: Support fs_context cgroup: store a reference to cgroup_ns into cgroup_fs_context cgroup1_get_tree(): separate "get cgroup_root to use" into a separate helper cgroup_do_mount(): massage calling conventions cgroup: stash cgroup_root reference into cgroup_fs_context cgroup2: switch to option-by-option parsing cgroup1: switch to option-by-option parsing cgroup: take options parsing into ->parse_monolithic() cgroup: fold cgroup1_mount() into cgroup1_get_tree() cgroup: start switching to fs_context ipc: Convert mqueue fs to fs_context proc: Add fs_context support to procfs ...

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma

2019-03-09T23:53:03Z

Pull rdma updates from Jason Gunthorpe: "This has been a slightly more active cycle than normal with ongoing core changes and quite a lot of collected driver updates. - Various driver fixes for bnxt_re, cxgb4, hns, mlx5, pvrdma, rxe - A new data transfer mode for HFI1 giving higher performance - Significant functional and bug fix update to the mlx5 On-Demand-Paging MR feature - A chip hang reset recovery system for hns - Change mm->pinned_vm to an atomic64 - Update bnxt_re to support a new 57500 chip - A sane netlink 'rdma link add' method for creating rxe devices and fixing the various unregistration race conditions in rxe's unregister flow - Allow lookup up objects by an ID over netlink - Various reworking of the core to driver interface: - drivers should not assume umem SGLs are in PAGE_SIZE chunks - ucontext is accessed via udata not other means - start to make the core code responsible for object memory allocation - drivers should convert struct device to struct ib_device via a helper - drivers have more tools to avoid use after unregister problems" * tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (280 commits) net/mlx5: ODP support for XRC transport is not enabled by default in FW IB/hfi1: Close race condition on user context disable and close RDMA/umem: Revert broken 'off by one' fix RDMA/umem: minor bug fix in error handling path RDMA/hns: Use GFP_ATOMIC in hns_roce_v2_modify_qp cxgb4: kfree mhp after the debug print IB/rdmavt: Fix concurrency panics in QP post_send and modify to error IB/rdmavt: Fix loopback send with invalidate ordering IB/iser: Fix dma_nents type definition IB/mlx5: Set correct write permissions for implicit ODP MR bnxt_re: Clean cq for kernel consumers only RDMA/uverbs: Don't do double free of allocated PD RDMA: Handle ucontext allocations by IB/core RDMA/core: Fix a WARN() message bnxt_re: fix the regression due to changes in alloc_pbl IB/mlx4: Increase the timeout for CM cache IB/core: Abort page fault handler silently during owning process exit IB/mlx5: Validate correct PD before prefetch MR IB/mlx5: Protect against prefetch of invalid MR RDMA/uverbs: Store PR pointer before it is overwritten ...

Merge branch 'for-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

2019-03-07T18:11:41Z

Pull cgroup updates from Tejun Heo: - Oleg's pids controller accounting update which gets rid of rcu delay in pids accounting updates - rstat (cgroup hierarchical stat collection mechanism) optimization - Doc updates * 'for-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cpuset: remove unused task_has_mempolicy() cgroup, rstat: Don't flush subtree root unless necessary cgroup: add documentation for pids.events file Documentation: cgroup-v2: eliminate markup warnings MAINTAINERS: Update cgroup entry cgroup/pids: turn cgroup_subsys->free() into cgroup_subsys->release() to fix the accounting

kernel: cgroup: add poll file operation

2019-03-06T05:07:17Z

Cgroup has a standardized poll/notification mechanism for waking all pollers on all fds when a filesystem node changes. To allow polling for custom events, add a .poll callback that can override the default. This is in preparation for pollable cgroup pressure files which have per-fd trigger configurations. Link: http://lkml.kernel.org/r/20190124211518.244221-3-surenb@google.com Signed-off-by: Johannes Weiner Signed-off-by: Suren Baghdasaryan Cc: Dennis Zhou Cc: Ingo Molnar Cc: Jens Axboe Cc: Li Zefan Cc: Peter Zijlstra Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

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

2019-03-05T16:26:13Z

Pull networking updates from David Miller: "Here we go, another merge window full of networking and #ebpf changes: 1) Snoop DHCPACKS in batman-adv to learn MAC/IP pairs in the DHCP range without dealing with floods of ARP traffic, from Linus Lüssing. 2) Throttle buffered multicast packet transmission in mt76, from Felix Fietkau. 3) Support adaptive interrupt moderation in ice, from Brett Creeley. 4) A lot of struct_size conversions, from Gustavo A. R. Silva. 5) Add peek/push/pop commands to bpftool, as well as bash completion, from Stanislav Fomichev. 6) Optimize sk_msg_clone(), from Vakul Garg. 7) Add SO_BINDTOIFINDEX, from David Herrmann. 8) Be more conservative with local resends due to local congestion, from Yuchung Cheng. 9) Allow vetoing of unsupported VXLAN FDBs, from Petr Machata. 10) Add health buffer support to devlink, from Eran Ben Elisha. 11) Add TXQ scheduling API to mac80211, from Toke Høiland-Jørgensen. 12) Add statistics to basic packet scheduler filter, from Cong Wang. 13) Add GRE tunnel support for mlxsw Spectrum-2, from Nir Dotan. 14) Lots of new IP tunneling forwarding tests, also from Nir Dotan. 15) Add 3ad stats to bonding, from Nikolay Aleksandrov. 16) Lots of probing improvements for bpftool, from Quentin Monnet. 17) Various nfp drive #ebpf JIT improvements from Jakub Kicinski. 18) Allow #ebpf programs to access gso_segs from skb shared info, from Eric Dumazet. 19) Add sock_diag support for AF_XDP sockets, from Björn Töpel. 20) Support 22260 iwlwifi devices, from Luca Coelho. 21) Use rbtree for ipv6 defragmentation, from Peter Oskolkov. 22) Add JMP32 instruction class support to #ebpf, from Jiong Wang. 23) Add spinlock support to #ebpf, from Alexei Starovoitov. 24) Support 256-bit keys and TLS 1.3 in ktls, from Dave Watson. 25) Add device infomation API to devlink, from Jakub Kicinski. 26) Add new timestamping socket options which are y2038 safe, from Deepa Dinamani. 27) Add RX checksum offloading for various sh_eth chips, from Sergei Shtylyov. 28) Flow offload infrastructure, from Pablo Neira Ayuso. 29) Numerous cleanups, improvements, and bug fixes to the PHY layer and many drivers from Heiner Kallweit. 30) Lots of changes to try and make packet scheduler classifiers run lockless as much as possible, from Vlad Buslov. 31) Support BCM957504 chip in bnxt_en driver, from Erik Burrows. 32) Add concurrency tests to tc-tests infrastructure, from Vlad Buslov. 33) Add hwmon support to aquantia, from Heiner Kallweit. 34) Allow 64-bit values for SO_MAX_PACING_RATE, from Eric Dumazet. And I would be remiss if I didn't thank the various major networking subsystem maintainers for integrating much of this work before I even saw it. Alexei Starovoitov, Daniel Borkmann, Pablo Neira Ayuso, Johannes Berg, Kalle Valo, and many others. Thank you!" * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (2207 commits) net/sched: avoid unused-label warning net: ignore sysctl_devconf_inherit_init_net without SYSCTL phy: mdio-mux: fix Kconfig dependencies net: phy: use phy_modify_mmd_changed in genphy_c45_an_config_aneg net: dsa: mv88e6xxx: add call to mv88e6xxx_ports_cmode_init to probe for new DSA framework selftest/net: Remove duplicate header sky2: Disable MSI on Dell Inspiron 1545 and Gateway P-79 net/mlx5e: Update tx reporter status in case channels were successfully opened devlink: Add support for direct reporter health state update devlink: Update reporter state to error even if recover aborted sctp: call iov_iter_revert() after sending ABORT team: Free BPF filter when unregistering netdev ip6mr: Do not call __IP6_INC_STATS() from preemptible context isdn: mISDN: Fix potential NULL pointer dereference of kzalloc net: dsa: mv88e6xxx: support in-band signalling on SGMII ports with external PHYs cxgb4/chtls: Prefix adapter flags with CXGB4 net-sysfs: Switch to bitmap_zalloc() mellanox: Switch to bitmap_zalloc() bpf: add test cases for non-pointer sanitiation logic mlxsw: i2c: Extend initialization by querying resources data ...

vfs: Add some logging to the core users of the fs_context log

2019-02-28T08:29:38Z

Add some logging to the core users of the fs_context log so that information can be extracted from them as to the reason for failure. Signed-off-by: David Howells Signed-off-by: Al Viro

cpuset: Use fs_context

2019-02-28T08:29:35Z

Make the cpuset filesystem use the filesystem context. This is potentially tricky as the cpuset fs is almost an alias for the cgroup filesystem, but with some special parameters. This can, however, be handled by setting up an appropriate cgroup filesystem and returning the root directory of that as the root dir of this one. Signed-off-by: David Howells cc: Tejun Heo Signed-off-by: Al Viro