Commit Graph

646 Commits

Author SHA1 Message Date
Waiman Long
11e5f407b6 cgroup/cpuset: Keep track of CPUs in isolated partitions
Add a new internal isolated_cpus mask to keep track of the CPUs that are in
isolated partitions. Expose that new cpumask as a new root-only control file
".cpuset.cpus.isolated".

tj: Updated patch description to reflect dropping __DEBUG__ prefix.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-11-12 15:07:41 -06:00
Yafang Shao
aecd408b7e cgroup: Add a new helper for cgroup1 hierarchy
A new helper is added for cgroup1 hierarchy:

- task_get_cgroup1
  Acquires the associated cgroup of a task within a specific cgroup1
  hierarchy. The cgroup1 hierarchy is identified by its hierarchy ID.

This helper function is added to facilitate the tracing of tasks within
a particular container or cgroup dir in BPF programs. It's important to
note that this helper is designed specifically for cgroup1 only.

tj: Use irsqsave/restore as suggested by Hou Tao <houtao@huaweicloud.com>.

Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Cc: Hou Tao <houtao@huaweicloud.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-11-09 13:25:47 -10:00
Yafang Shao
0008454e8f cgroup: Add annotation for holding namespace_sem in current_cgns_cgroup_from_root()
When I initially examined the function current_cgns_cgroup_from_root(), I
was perplexed by its lack of holding cgroup_mutex. However, after Michal
explained the reason[0] to me, I realized that it already holds the
namespace_sem. I believe this intricacy could also confuse others, so it
would be advisable to include an annotation for clarification.

After we replace the cgroup_mutex with RCU read lock, if current doesn't
hold the namespace_sem, the root cgroup will be NULL. So let's add a
WARN_ON_ONCE() for it.

[0]. https://lore.kernel.org/bpf/afdnpo3jz2ic2ampud7swd6so5carkilts2mkygcaw67vbw6yh@5b5mncf7qyet

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Cc: Michal Koutny <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-11-09 13:25:47 -10:00
Yafang Shao
9067d90006 cgroup: Eliminate the need for cgroup_mutex in proc_cgroup_show()
The cgroup root_list is already RCU-safe. Therefore, we can replace the
cgroup_mutex with the RCU read lock in some particular paths. This change
will be particularly beneficial for frequent operations, such as
`cat /proc/self/cgroup`, in a cgroup1-based container environment.

I did stress tests with this change, as outlined below
(with CONFIG_PROVE_RCU_LIST enabled):

- Continuously mounting and unmounting named cgroups in some tasks,
  for example:

  cgrp_name=$1
  while true
  do
      mount -t cgroup -o none,name=$cgrp_name none /$cgrp_name
      umount /$cgrp_name
  done

- Continuously triggering proc_cgroup_show() in some tasks concurrently,
  for example:
  while true; do cat /proc/self/cgroup > /dev/null; done

They can ran successfully after implementing this change, with no RCU
warnings in dmesg.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-11-09 13:25:47 -10:00
Yafang Shao
d23b5c5777 cgroup: Make operations on the cgroup root_list RCU safe
At present, when we perform operations on the cgroup root_list, we must
hold the cgroup_mutex, which is a relatively heavyweight lock. In reality,
we can make operations on this list RCU-safe, eliminating the need to hold
the cgroup_mutex during traversal. Modifications to the list only occur in
the cgroup root setup and destroy paths, which should be infrequent in a
production environment. In contrast, traversal may occur frequently.
Therefore, making it RCU-safe would be beneficial.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-11-09 13:25:47 -10:00
Yafang Shao
96a2b48e5e cgroup: Remove unnecessary list_empty()
The root hasn't been removed from the root_list, so the list can't be NULL.
However, if it had been removed, attempting to destroy it once more is not
possible. Let's replace this with WARN_ON_ONCE() for clarity.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-11-09 13:25:46 -10:00
Linus Torvalds
ecae0bd517 Many singleton patches against the MM code. The patch series which are
included in this merge do the following:
 
 - Kemeng Shi has contributed some compation maintenance work in the
   series "Fixes and cleanups to compaction".
 
 - Joel Fernandes has a patchset ("Optimize mremap during mutual
   alignment within PMD") which fixes an obscure issue with mremap()'s
   pagetable handling during a subsequent exec(), based upon an
   implementation which Linus suggested.
 
 - More DAMON/DAMOS maintenance and feature work from SeongJae Park i the
   following patch series:
 
 	mm/damon: misc fixups for documents, comments and its tracepoint
 	mm/damon: add a tracepoint for damos apply target regions
 	mm/damon: provide pseudo-moving sum based access rate
 	mm/damon: implement DAMOS apply intervals
 	mm/damon/core-test: Fix memory leaks in core-test
 	mm/damon/sysfs-schemes: Do DAMOS tried regions update for only one apply interval
 
 - In the series "Do not try to access unaccepted memory" Adrian Hunter
   provides some fixups for the recently-added "unaccepted memory' feature.
   To increase the feature's checking coverage.  "Plug a few gaps where
   RAM is exposed without checking if it is unaccepted memory".
 
 - In the series "cleanups for lockless slab shrink" Qi Zheng has done
   some maintenance work which is preparation for the lockless slab
   shrinking code.
 
 - Qi Zheng has redone the earlier (and reverted) attempt to make slab
   shrinking lockless in the series "use refcount+RCU method to implement
   lockless slab shrink".
 
 - David Hildenbrand contributes some maintenance work for the rmap code
   in the series "Anon rmap cleanups".
 
 - Kefeng Wang does more folio conversions and some maintenance work in
   the migration code.  Series "mm: migrate: more folio conversion and
   unification".
 
 - Matthew Wilcox has fixed an issue in the buffer_head code which was
   causing long stalls under some heavy memory/IO loads.  Some cleanups
   were added on the way.  Series "Add and use bdev_getblk()".
 
 - In the series "Use nth_page() in place of direct struct page
   manipulation" Zi Yan has fixed a potential issue with the direct
   manipulation of hugetlb page frames.
 
 - In the series "mm: hugetlb: Skip initialization of gigantic tail
   struct pages if freed by HVO" has improved our handling of gigantic
   pages in the hugetlb vmmemmep optimizaton code.  This provides
   significant boot time improvements when significant amounts of gigantic
   pages are in use.
 
 - Matthew Wilcox has sent the series "Small hugetlb cleanups" - code
   rationalization and folio conversions in the hugetlb code.
 
 - Yin Fengwei has improved mlock()'s handling of large folios in the
   series "support large folio for mlock"
 
 - In the series "Expose swapcache stat for memcg v1" Liu Shixin has
   added statistics for memcg v1 users which are available (and useful)
   under memcg v2.
 
 - Florent Revest has enhanced the MDWE (Memory-Deny-Write-Executable)
   prctl so that userspace may direct the kernel to not automatically
   propagate the denial to child processes.  The series is named "MDWE
   without inheritance".
 
 - Kefeng Wang has provided the series "mm: convert numa balancing
   functions to use a folio" which does what it says.
 
 - In the series "mm/ksm: add fork-exec support for prctl" Stefan Roesch
   makes is possible for a process to propagate KSM treatment across
   exec().
 
 - Huang Ying has enhanced memory tiering's calculation of memory
   distances.  This is used to permit the dax/kmem driver to use "high
   bandwidth memory" in addition to Optane Data Center Persistent Memory
   Modules (DCPMM).  The series is named "memory tiering: calculate
   abstract distance based on ACPI HMAT"
 
 - In the series "Smart scanning mode for KSM" Stefan Roesch has
   optimized KSM by teaching it to retain and use some historical
   information from previous scans.
 
 - Yosry Ahmed has fixed some inconsistencies in memcg statistics in the
   series "mm: memcg: fix tracking of pending stats updates values".
 
 - In the series "Implement IOCTL to get and optionally clear info about
   PTEs" Peter Xu has added an ioctl to /proc/<pid>/pagemap which permits
   us to atomically read-then-clear page softdirty state.  This is mainly
   used by CRIU.
 
 - Hugh Dickins contributed the series "shmem,tmpfs: general maintenance"
   - a bunch of relatively minor maintenance tweaks to this code.
 
 - Matthew Wilcox has increased the use of the VMA lock over file-backed
   page faults in the series "Handle more faults under the VMA lock".  Some
   rationalizations of the fault path became possible as a result.
 
 - In the series "mm/rmap: convert page_move_anon_rmap() to
   folio_move_anon_rmap()" David Hildenbrand has implemented some cleanups
   and folio conversions.
 
 - In the series "various improvements to the GUP interface" Lorenzo
   Stoakes has simplified and improved the GUP interface with an eye to
   providing groundwork for future improvements.
 
 - Andrey Konovalov has sent along the series "kasan: assorted fixes and
   improvements" which does those things.
 
 - Some page allocator maintenance work from Kemeng Shi in the series
   "Two minor cleanups to break_down_buddy_pages".
 
 - In thes series "New selftest for mm" Breno Leitao has developed
   another MM self test which tickles a race we had between madvise() and
   page faults.
 
 - In the series "Add folio_end_read" Matthew Wilcox provides cleanups
   and an optimization to the core pagecache code.
 
 - Nhat Pham has added memcg accounting for hugetlb memory in the series
   "hugetlb memcg accounting".
 
 - Cleanups and rationalizations to the pagemap code from Lorenzo
   Stoakes, in the series "Abstract vma_merge() and split_vma()".
 
 - Audra Mitchell has fixed issues in the procfs page_owner code's new
   timestamping feature which was causing some misbehaviours.  In the
   series "Fix page_owner's use of free timestamps".
 
 - Lorenzo Stoakes has fixed the handling of new mappings of sealed files
   in the series "permit write-sealed memfd read-only shared mappings".
 
 - Mike Kravetz has optimized the hugetlb vmemmap optimization in the
   series "Batch hugetlb vmemmap modification operations".
 
 - Some buffer_head folio conversions and cleanups from Matthew Wilcox in
   the series "Finish the create_empty_buffers() transition".
 
 - As a page allocator performance optimization Huang Ying has added
   automatic tuning to the allocator's per-cpu-pages feature, in the series
   "mm: PCP high auto-tuning".
 
 - Roman Gushchin has contributed the patchset "mm: improve performance
   of accounted kernel memory allocations" which improves their performance
   by ~30% as measured by a micro-benchmark.
 
 - folio conversions from Kefeng Wang in the series "mm: convert page
   cpupid functions to folios".
 
 - Some kmemleak fixups in Liu Shixin's series "Some bugfix about
   kmemleak".
 
 - Qi Zheng has improved our handling of memoryless nodes by keeping them
   off the allocation fallback list.  This is done in the series "handle
   memoryless nodes more appropriately".
 
 - khugepaged conversions from Vishal Moola in the series "Some
   khugepaged folio conversions".
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Merge tag 'mm-stable-2023-11-01-14-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:
 "Many singleton patches against the MM code. The patch series which are
  included in this merge do the following:

   - Kemeng Shi has contributed some compation maintenance work in the
     series 'Fixes and cleanups to compaction'

   - Joel Fernandes has a patchset ('Optimize mremap during mutual
     alignment within PMD') which fixes an obscure issue with mremap()'s
     pagetable handling during a subsequent exec(), based upon an
     implementation which Linus suggested

   - More DAMON/DAMOS maintenance and feature work from SeongJae Park i
     the following patch series:

	mm/damon: misc fixups for documents, comments and its tracepoint
	mm/damon: add a tracepoint for damos apply target regions
	mm/damon: provide pseudo-moving sum based access rate
	mm/damon: implement DAMOS apply intervals
	mm/damon/core-test: Fix memory leaks in core-test
	mm/damon/sysfs-schemes: Do DAMOS tried regions update for only one apply interval

   - In the series 'Do not try to access unaccepted memory' Adrian
     Hunter provides some fixups for the recently-added 'unaccepted
     memory' feature. To increase the feature's checking coverage. 'Plug
     a few gaps where RAM is exposed without checking if it is
     unaccepted memory'

   - In the series 'cleanups for lockless slab shrink' Qi Zheng has done
     some maintenance work which is preparation for the lockless slab
     shrinking code

   - Qi Zheng has redone the earlier (and reverted) attempt to make slab
     shrinking lockless in the series 'use refcount+RCU method to
     implement lockless slab shrink'

   - David Hildenbrand contributes some maintenance work for the rmap
     code in the series 'Anon rmap cleanups'

   - Kefeng Wang does more folio conversions and some maintenance work
     in the migration code. Series 'mm: migrate: more folio conversion
     and unification'

   - Matthew Wilcox has fixed an issue in the buffer_head code which was
     causing long stalls under some heavy memory/IO loads. Some cleanups
     were added on the way. Series 'Add and use bdev_getblk()'

   - In the series 'Use nth_page() in place of direct struct page
     manipulation' Zi Yan has fixed a potential issue with the direct
     manipulation of hugetlb page frames

   - In the series 'mm: hugetlb: Skip initialization of gigantic tail
     struct pages if freed by HVO' has improved our handling of gigantic
     pages in the hugetlb vmmemmep optimizaton code. This provides
     significant boot time improvements when significant amounts of
     gigantic pages are in use

   - Matthew Wilcox has sent the series 'Small hugetlb cleanups' - code
     rationalization and folio conversions in the hugetlb code

   - Yin Fengwei has improved mlock()'s handling of large folios in the
     series 'support large folio for mlock'

   - In the series 'Expose swapcache stat for memcg v1' Liu Shixin has
     added statistics for memcg v1 users which are available (and
     useful) under memcg v2

   - Florent Revest has enhanced the MDWE (Memory-Deny-Write-Executable)
     prctl so that userspace may direct the kernel to not automatically
     propagate the denial to child processes. The series is named 'MDWE
     without inheritance'

   - Kefeng Wang has provided the series 'mm: convert numa balancing
     functions to use a folio' which does what it says

   - In the series 'mm/ksm: add fork-exec support for prctl' Stefan
     Roesch makes is possible for a process to propagate KSM treatment
     across exec()

   - Huang Ying has enhanced memory tiering's calculation of memory
     distances. This is used to permit the dax/kmem driver to use 'high
     bandwidth memory' in addition to Optane Data Center Persistent
     Memory Modules (DCPMM). The series is named 'memory tiering:
     calculate abstract distance based on ACPI HMAT'

   - In the series 'Smart scanning mode for KSM' Stefan Roesch has
     optimized KSM by teaching it to retain and use some historical
     information from previous scans

   - Yosry Ahmed has fixed some inconsistencies in memcg statistics in
     the series 'mm: memcg: fix tracking of pending stats updates
     values'

   - In the series 'Implement IOCTL to get and optionally clear info
     about PTEs' Peter Xu has added an ioctl to /proc/<pid>/pagemap
     which permits us to atomically read-then-clear page softdirty
     state. This is mainly used by CRIU

   - Hugh Dickins contributed the series 'shmem,tmpfs: general
     maintenance', a bunch of relatively minor maintenance tweaks to
     this code

   - Matthew Wilcox has increased the use of the VMA lock over
     file-backed page faults in the series 'Handle more faults under the
     VMA lock'. Some rationalizations of the fault path became possible
     as a result

   - In the series 'mm/rmap: convert page_move_anon_rmap() to
     folio_move_anon_rmap()' David Hildenbrand has implemented some
     cleanups and folio conversions

   - In the series 'various improvements to the GUP interface' Lorenzo
     Stoakes has simplified and improved the GUP interface with an eye
     to providing groundwork for future improvements

   - Andrey Konovalov has sent along the series 'kasan: assorted fixes
     and improvements' which does those things

   - Some page allocator maintenance work from Kemeng Shi in the series
     'Two minor cleanups to break_down_buddy_pages'

   - In thes series 'New selftest for mm' Breno Leitao has developed
     another MM self test which tickles a race we had between madvise()
     and page faults

   - In the series 'Add folio_end_read' Matthew Wilcox provides cleanups
     and an optimization to the core pagecache code

   - Nhat Pham has added memcg accounting for hugetlb memory in the
     series 'hugetlb memcg accounting'

   - Cleanups and rationalizations to the pagemap code from Lorenzo
     Stoakes, in the series 'Abstract vma_merge() and split_vma()'

   - Audra Mitchell has fixed issues in the procfs page_owner code's new
     timestamping feature which was causing some misbehaviours. In the
     series 'Fix page_owner's use of free timestamps'

   - Lorenzo Stoakes has fixed the handling of new mappings of sealed
     files in the series 'permit write-sealed memfd read-only shared
     mappings'

   - Mike Kravetz has optimized the hugetlb vmemmap optimization in the
     series 'Batch hugetlb vmemmap modification operations'

   - Some buffer_head folio conversions and cleanups from Matthew Wilcox
     in the series 'Finish the create_empty_buffers() transition'

   - As a page allocator performance optimization Huang Ying has added
     automatic tuning to the allocator's per-cpu-pages feature, in the
     series 'mm: PCP high auto-tuning'

   - Roman Gushchin has contributed the patchset 'mm: improve
     performance of accounted kernel memory allocations' which improves
     their performance by ~30% as measured by a micro-benchmark

   - folio conversions from Kefeng Wang in the series 'mm: convert page
     cpupid functions to folios'

   - Some kmemleak fixups in Liu Shixin's series 'Some bugfix about
     kmemleak'

   - Qi Zheng has improved our handling of memoryless nodes by keeping
     them off the allocation fallback list. This is done in the series
     'handle memoryless nodes more appropriately'

   - khugepaged conversions from Vishal Moola in the series 'Some
     khugepaged folio conversions'"

[ bcachefs conflicts with the dynamically allocated shrinkers have been
  resolved as per Stephen Rothwell in

     https://lore.kernel.org/all/20230913093553.4290421e@canb.auug.org.au/

  with help from Qi Zheng.

  The clone3 test filtering conflict was half-arsed by yours truly ]

* tag 'mm-stable-2023-11-01-14-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (406 commits)
  mm/damon/sysfs: update monitoring target regions for online input commit
  mm/damon/sysfs: remove requested targets when online-commit inputs
  selftests: add a sanity check for zswap
  Documentation: maple_tree: fix word spelling error
  mm/vmalloc: fix the unchecked dereference warning in vread_iter()
  zswap: export compression failure stats
  Documentation: ubsan: drop "the" from article title
  mempolicy: migration attempt to match interleave nodes
  mempolicy: mmap_lock is not needed while migrating folios
  mempolicy: alloc_pages_mpol() for NUMA policy without vma
  mm: add page_rmappable_folio() wrapper
  mempolicy: remove confusing MPOL_MF_LAZY dead code
  mempolicy: mpol_shared_policy_init() without pseudo-vma
  mempolicy trivia: use pgoff_t in shared mempolicy tree
  mempolicy trivia: slightly more consistent naming
  mempolicy trivia: delete those ancient pr_debug()s
  mempolicy: fix migrate_pages(2) syscall return nr_failed
  kernfs: drop shared NUMA mempolicy hooks
  hugetlbfs: drop shared NUMA mempolicy pretence
  mm/damon/sysfs-test: add a unit test for damon_sysfs_set_targets()
  ...
2023-11-02 19:38:47 -10:00
Linus Torvalds
89ed67ef12 Networking changes for 6.7.
Core & protocols
 ----------------
 
  - Support usec resolution of TCP timestamps, enabled selectively by
    a route attribute.
 
  - Defer regular TCP ACK while processing socket backlog, try to send
    a cumulative ACK at the end. Increase single TCP flow performance
    on a 200Gbit NIC by 20% (100Gbit -> 120Gbit).
 
  - The Fair Queuing (FQ) packet scheduler:
    - add built-in 3 band prio / WRR scheduling
    - support bypass if the qdisc is mostly idle (5% speed up for TCP RR)
    - improve inactive flow reporting
    - optimize the layout of structures for better cache locality
 
  - Support TCP Authentication Option (RFC 5925, TCP-AO), a more modern
    replacement for the old MD5 option.
 
  - Add more retransmission timeout (RTO) related statistics to TCP_INFO.
 
  - Support sending fragmented skbs over vsock sockets.
 
  - Make sure we send SIGPIPE for vsock sockets if socket was shutdown().
 
  - Add sysctl for ignoring lower limit on lifetime in Router
    Advertisement PIO, based on an in-progress IETF draft.
 
  - Add sysctl to control activation of TCP ping-pong mode.
 
  - Add sysctl to make connection timeout in MPTCP configurable.
 
  - Support rcvlowat and notsent_lowat on MPTCP sockets, to help apps
    limit the number of wakeups.
 
  - Support netlink GET for MDB (multicast forwarding), allowing user
    space to request a single MDB entry instead of dumping the entire
    table.
 
  - Support selective FDB flushing in the VXLAN tunnel driver.
 
  - Allow limiting learned FDB entries in bridges, prevent OOM attacks.
 
  - Allow controlling via configfs netconsole targets which were created
    via the kernel cmdline at boot, rather than via configfs at runtime.
 
  - Support multiple PTP timestamp event queue readers with different
    filters.
 
  - MCTP over I3C.
 
 BPF
 ---
 
  - Add new veth-like netdevice where BPF program defines the logic
    of the xmit routine. It can operate in L3 and L2 mode.
 
  - Support exceptions - allow asserting conditions which should
    never be true but are hard for the verifier to infer.
    With some extra flexibility around handling of the exit / failure.
    https://lwn.net/Articles/938435/
 
  - Add support for local per-cpu kptr, allow allocating and storing
    per-cpu objects in maps. Access to those objects operates on
    the value for the current CPU. This allows to deprecate local
    one-off implementations of per-CPU storage like
    BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE maps.
 
  - Extend cgroup BPF sockaddr hooks for UNIX sockets. The use case is
    for systemd to re-implement the LogNamespace feature which allows
    running multiple instances of systemd-journald to process the logs
    of different services.
 
  - Enable open-coded task_vma iteration, after maple tree conversion
    made it hard to directly walk VMAs in tracing programs.
 
  - Add open-coded task, css_task and css iterator support.
    One of the use cases is customizable OOM victim selection via BPF.
 
  - Allow source address selection with bpf_*_fib_lookup().
 
  - Add ability to pin BPF timer to the current CPU.
 
  - Prevent creation of infinite loops by combining tail calls and
    fentry/fexit programs.
 
  - Add missed stats for kprobes to retrieve the number of missed kprobe
    executions and subsequent executions of BPF programs.
 
  - Inherit system settings for CPU security mitigations.
 
  - Add BPF v4 CPU instruction support for arm32 and s390x.
 
 Changes to common code
 ----------------------
 
  - overflow: add DEFINE_FLEX() for on-stack definition of structs
    with flexible array members.
 
  - Process doc update with more guidance for reviewers.
 
 Driver API
 ----------
 
  - Simplify locking in WiFi (cfg80211 and mac80211 layers), use wiphy
    mutex in most places and remove a lot of smaller locks.
 
  - Create a common DPLL configuration API. Allow configuring
    and querying state of PLL circuits used for clock syntonization,
    in network time distribution.
 
  - Unify fragmented and full page allocation APIs in page pool code.
    Let drivers be ignorant of PAGE_SIZE.
 
  - Rework PHY state machine to avoid races with calls to phy_stop().
 
  - Notify DSA drivers of MAC address changes on user ports, improve
    correctness of offloads which depend on matching port MAC addresses.
 
  - Allow antenna control on injected WiFi frames.
 
  - Reduce the number of variants of napi_schedule().
 
  - Simplify error handling when composing devlink health messages.
 
 Misc
 ----
 
  - A lot of KCSAN data race "fixes", from Eric.
 
  - A lot of __counted_by() annotations, from Kees.
 
  - A lot of strncpy -> strscpy and printf format fixes.
 
  - Replace master/slave terminology with conduit/user in DSA drivers.
 
  - Handful of KUnit tests for netdev and WiFi core.
 
 Removed
 -------
 
  - AppleTalk COPS.
 
  - AppleTalk ipddp.
 
  - TI AR7 CPMAC Ethernet driver.
 
 Drivers
 -------
 
  - Ethernet high-speed NICs:
    - Intel (100G, ice, idpf):
      - add a driver for the Intel E2000 IPUs
      - make CRC/FCS stripping configurable
      - cross-timestamping for E823 devices
      - basic support for E830 devices
      - use aux-bus for managing client drivers
      - i40e: report firmware versions via devlink
    - nVidia/Mellanox:
      - support 4-port NICs
      - increase max number of channels to 256
      - optimize / parallelize SF creation flow
    - Broadcom (bnxt):
      - enhance NIC temperature reporting
      - support PAM4 speeds and lane configuration
    - Marvell OcteonTX2:
      - PTP pulse-per-second output support
      - enable hardware timestamping for VFs
    - Solarflare/AMD:
      - conntrack NAT offload and offload for tunnels
    - Wangxun (ngbe/txgbe):
      - expose HW statistics
    - Pensando/AMD:
      - support PCI level reset
      - narrow down the condition under which skbs are linearized
    - Netronome/Corigine (nfp):
      - support CHACHA20-POLY1305 crypto in IPsec offload
 
  - Ethernet NICs embedded, slower, virtual:
    - Synopsys (stmmac):
      - add Loongson-1 SoC support
      - enable use of HW queues with no offload capabilities
      - enable PPS input support on all 5 channels
      - increase TX coalesce timer to 5ms
    - RealTek USB (r8152): improve efficiency of Rx by using GRO frags
    - xen: support SW packet timestamping
    - add drivers for implementations based on TI's PRUSS (AM64x EVM)
 
  - nVidia/Mellanox Ethernet datacenter switches:
    - avoid poor HW resource use on Spectrum-4 by better block selection
      for IPv6 multicast forwarding and ordering of blocks in ACL region
 
  - Ethernet embedded switches:
    - Microchip:
      - support configuring the drive strength for EMI compliance
      - ksz9477: partial ACL support
      - ksz9477: HSR offload
      - ksz9477: Wake on LAN
    - Realtek:
      - rtl8366rb: respect device tree config of the CPU port
 
  - Ethernet PHYs:
    - support Broadcom BCM5221 PHYs
    - TI dp83867: support hardware LED blinking
 
  - CAN:
    - add support for Linux-PHY based CAN transceivers
    - at91_can: clean up and use rx-offload helpers
 
  - WiFi:
    - MediaTek (mt76):
      - new sub-driver for mt7925 USB/PCIe devices
      - HW wireless <> Ethernet bridging in MT7988 chips
      - mt7603/mt7628 stability improvements
    - Qualcomm (ath12k):
      - WCN7850:
        - enable 320 MHz channels in 6 GHz band
        - hardware rfkill support
        - enable IEEE80211_HW_SINGLE_SCAN_ON_ALL_BANDS
          to make scan faster
        - read board data variant name from SMBIOS
      - QCN9274: mesh support
    - RealTek (rtw89):
      - TDMA-based multi-channel concurrency (MCC)
    - Silicon Labs (wfx):
      - Remain-On-Channel (ROC) support
 
  - Bluetooth:
    - ISO: many improvements for broadcast support
    - mark BCM4378/BCM4387 as BROKEN_LE_CODED
    - add support for QCA2066
    - btmtksdio: enable Bluetooth wakeup from suspend
 
 Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'net-next-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

Pull networking updates from Jakub Kicinski:
 "Core & protocols:

   - Support usec resolution of TCP timestamps, enabled selectively by a
     route attribute.

   - Defer regular TCP ACK while processing socket backlog, try to send
     a cumulative ACK at the end. Increase single TCP flow performance
     on a 200Gbit NIC by 20% (100Gbit -> 120Gbit).

   - The Fair Queuing (FQ) packet scheduler:
       - add built-in 3 band prio / WRR scheduling
       - support bypass if the qdisc is mostly idle (5% speed up for TCP RR)
       - improve inactive flow reporting
       - optimize the layout of structures for better cache locality

   - Support TCP Authentication Option (RFC 5925, TCP-AO), a more modern
     replacement for the old MD5 option.

   - Add more retransmission timeout (RTO) related statistics to
     TCP_INFO.

   - Support sending fragmented skbs over vsock sockets.

   - Make sure we send SIGPIPE for vsock sockets if socket was
     shutdown().

   - Add sysctl for ignoring lower limit on lifetime in Router
     Advertisement PIO, based on an in-progress IETF draft.

   - Add sysctl to control activation of TCP ping-pong mode.

   - Add sysctl to make connection timeout in MPTCP configurable.

   - Support rcvlowat and notsent_lowat on MPTCP sockets, to help apps
     limit the number of wakeups.

   - Support netlink GET for MDB (multicast forwarding), allowing user
     space to request a single MDB entry instead of dumping the entire
     table.

   - Support selective FDB flushing in the VXLAN tunnel driver.

   - Allow limiting learned FDB entries in bridges, prevent OOM attacks.

   - Allow controlling via configfs netconsole targets which were
     created via the kernel cmdline at boot, rather than via configfs at
     runtime.

   - Support multiple PTP timestamp event queue readers with different
     filters.

   - MCTP over I3C.

  BPF:

   - Add new veth-like netdevice where BPF program defines the logic of
     the xmit routine. It can operate in L3 and L2 mode.

   - Support exceptions - allow asserting conditions which should never
     be true but are hard for the verifier to infer. With some extra
     flexibility around handling of the exit / failure:

          https://lwn.net/Articles/938435/

   - Add support for local per-cpu kptr, allow allocating and storing
     per-cpu objects in maps. Access to those objects operates on the
     value for the current CPU.

     This allows to deprecate local one-off implementations of per-CPU
     storage like BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE maps.

   - Extend cgroup BPF sockaddr hooks for UNIX sockets. The use case is
     for systemd to re-implement the LogNamespace feature which allows
     running multiple instances of systemd-journald to process the logs
     of different services.

   - Enable open-coded task_vma iteration, after maple tree conversion
     made it hard to directly walk VMAs in tracing programs.

   - Add open-coded task, css_task and css iterator support. One of the
     use cases is customizable OOM victim selection via BPF.

   - Allow source address selection with bpf_*_fib_lookup().

   - Add ability to pin BPF timer to the current CPU.

   - Prevent creation of infinite loops by combining tail calls and
     fentry/fexit programs.

   - Add missed stats for kprobes to retrieve the number of missed
     kprobe executions and subsequent executions of BPF programs.

   - Inherit system settings for CPU security mitigations.

   - Add BPF v4 CPU instruction support for arm32 and s390x.

  Changes to common code:

   - overflow: add DEFINE_FLEX() for on-stack definition of structs with
     flexible array members.

   - Process doc update with more guidance for reviewers.

  Driver API:

   - Simplify locking in WiFi (cfg80211 and mac80211 layers), use wiphy
     mutex in most places and remove a lot of smaller locks.

   - Create a common DPLL configuration API. Allow configuring and
     querying state of PLL circuits used for clock syntonization, in
     network time distribution.

   - Unify fragmented and full page allocation APIs in page pool code.
     Let drivers be ignorant of PAGE_SIZE.

   - Rework PHY state machine to avoid races with calls to phy_stop().

   - Notify DSA drivers of MAC address changes on user ports, improve
     correctness of offloads which depend on matching port MAC
     addresses.

   - Allow antenna control on injected WiFi frames.

   - Reduce the number of variants of napi_schedule().

   - Simplify error handling when composing devlink health messages.

  Misc:

   - A lot of KCSAN data race "fixes", from Eric.

   - A lot of __counted_by() annotations, from Kees.

   - A lot of strncpy -> strscpy and printf format fixes.

   - Replace master/slave terminology with conduit/user in DSA drivers.

   - Handful of KUnit tests for netdev and WiFi core.

  Removed:

   - AppleTalk COPS.

   - AppleTalk ipddp.

   - TI AR7 CPMAC Ethernet driver.

  Drivers:

   - Ethernet high-speed NICs:
      - Intel (100G, ice, idpf):
         - add a driver for the Intel E2000 IPUs
         - make CRC/FCS stripping configurable
         - cross-timestamping for E823 devices
         - basic support for E830 devices
         - use aux-bus for managing client drivers
         - i40e: report firmware versions via devlink
      - nVidia/Mellanox:
         - support 4-port NICs
         - increase max number of channels to 256
         - optimize / parallelize SF creation flow
      - Broadcom (bnxt):
         - enhance NIC temperature reporting
         - support PAM4 speeds and lane configuration
      - Marvell OcteonTX2:
         - PTP pulse-per-second output support
         - enable hardware timestamping for VFs
      - Solarflare/AMD:
         - conntrack NAT offload and offload for tunnels
      - Wangxun (ngbe/txgbe):
         - expose HW statistics
      - Pensando/AMD:
         - support PCI level reset
         - narrow down the condition under which skbs are linearized
      - Netronome/Corigine (nfp):
         - support CHACHA20-POLY1305 crypto in IPsec offload

   - Ethernet NICs embedded, slower, virtual:
      - Synopsys (stmmac):
         - add Loongson-1 SoC support
         - enable use of HW queues with no offload capabilities
         - enable PPS input support on all 5 channels
         - increase TX coalesce timer to 5ms
      - RealTek USB (r8152): improve efficiency of Rx by using GRO frags
      - xen: support SW packet timestamping
      - add drivers for implementations based on TI's PRUSS (AM64x EVM)

   - nVidia/Mellanox Ethernet datacenter switches:
      - avoid poor HW resource use on Spectrum-4 by better block
        selection for IPv6 multicast forwarding and ordering of blocks
        in ACL region

   - Ethernet embedded switches:
      - Microchip:
         - support configuring the drive strength for EMI compliance
         - ksz9477: partial ACL support
         - ksz9477: HSR offload
         - ksz9477: Wake on LAN
      - Realtek:
         - rtl8366rb: respect device tree config of the CPU port

   - Ethernet PHYs:
      - support Broadcom BCM5221 PHYs
      - TI dp83867: support hardware LED blinking

   - CAN:
      - add support for Linux-PHY based CAN transceivers
      - at91_can: clean up and use rx-offload helpers

   - WiFi:
      - MediaTek (mt76):
         - new sub-driver for mt7925 USB/PCIe devices
         - HW wireless <> Ethernet bridging in MT7988 chips
         - mt7603/mt7628 stability improvements
      - Qualcomm (ath12k):
         - WCN7850:
            - enable 320 MHz channels in 6 GHz band
            - hardware rfkill support
            - enable IEEE80211_HW_SINGLE_SCAN_ON_ALL_BANDS to
              make scan faster
            - read board data variant name from SMBIOS
        - QCN9274: mesh support
      - RealTek (rtw89):
         - TDMA-based multi-channel concurrency (MCC)
      - Silicon Labs (wfx):
         - Remain-On-Channel (ROC) support

   - Bluetooth:
      - ISO: many improvements for broadcast support
      - mark BCM4378/BCM4387 as BROKEN_LE_CODED
      - add support for QCA2066
      - btmtksdio: enable Bluetooth wakeup from suspend"

* tag 'net-next-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1816 commits)
  net: pcs: xpcs: Add 2500BASE-X case in get state for XPCS drivers
  net: bpf: Use sockopt_lock_sock() in ip_sock_set_tos()
  net: mana: Use xdp_set_features_flag instead of direct assignment
  vxlan: Cleanup IFLA_VXLAN_PORT_RANGE entry in vxlan_get_size()
  iavf: delete the iavf client interface
  iavf: add a common function for undoing the interrupt scheme
  iavf: use unregister_netdev
  iavf: rely on netdev's own registered state
  iavf: fix the waiting time for initial reset
  iavf: in iavf_down, don't queue watchdog_task if comms failed
  iavf: simplify mutex_trylock+sleep loops
  iavf: fix comments about old bit locks
  doc/netlink: Update schema to support cmd-cnt-name and cmd-max-name
  tools: ynl: introduce option to process unknown attributes or types
  ipvlan: properly track tx_errors
  netdevsim: Block until all devices are released
  nfp: using napi_build_skb() to replace build_skb()
  net: dsa: microchip: ksz9477: Fix spelling mistake "Enery" -> "Energy"
  net: dsa: microchip: Ensure Stable PME Pin State for Wake-on-LAN
  net: dsa: microchip: Refactor switch shutdown routine for WoL preparation
  ...
2023-10-31 05:10:11 -10:00
Linus Torvalds
5a6a09e971 cgroup: Changes for v6.7
* cpuset now supports remote partitions where CPUs can be reserved for
   exclusive use down the tree without requiring all the intermediate nodes
   to be partitions. This makes it easier to use partitions without modifying
   existing cgroup hierarchy.
 
 * cpuset partition configuration behavior improvement.
 
 * cgroup_favordynmods= boot param added to allow setting the flag on boot on
   cgroup1.
 
 * Misc code and doc updates.
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Merge tag 'cgroup-for-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup updates from Tejun Heo:

 - cpuset now supports remote partitions where CPUs can be reserved for
   exclusive use down the tree without requiring all the intermediate
   nodes to be partitions. This makes it easier to use partitions
   without modifying existing cgroup hierarchy.

 - cpuset partition configuration behavior improvement

 - cgroup_favordynmods= boot param added to allow setting the flag on
   boot on cgroup1

 - Misc code and doc updates

* tag 'cgroup-for-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  docs/cgroup: Add the list of threaded controllers to cgroup-v2.rst
  cgroup: use legacy_name for cgroup v1 disable info
  cgroup/cpuset: Cleanup signedness issue in cpu_exclusive_check()
  cgroup/cpuset: Enable invalid to valid local partition transition
  cgroup: add cgroup_favordynmods= command-line option
  cgroup/cpuset: Extend test_cpuset_prs.sh to test remote partition
  cgroup/cpuset: Documentation update for partition
  cgroup/cpuset: Check partition conflict with housekeeping setup
  cgroup/cpuset: Introduce remote partition
  cgroup/cpuset: Add cpuset.cpus.exclusive for v2
  cgroup/cpuset: Add cpuset.cpus.exclusive.effective for v2
  cgroup/cpuset: Fix load balance state in update_partition_sd_lb()
  cgroup: Avoid extra dereference in css_populate_dir()
  cgroup: Check for ret during cgroup1_base_files cft addition
2023-10-30 20:58:48 -10:00
Jakub Kicinski
c6f9b7138b bpf-next-for-netdev
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Merge tag 'for-netdev' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Daniel Borkmann says:

====================
pull-request: bpf-next 2023-10-26

We've added 51 non-merge commits during the last 10 day(s) which contain
a total of 75 files changed, 5037 insertions(+), 200 deletions(-).

The main changes are:

1) Add open-coded task, css_task and css iterator support.
   One of the use cases is customizable OOM victim selection via BPF,
   from Chuyi Zhou.

2) Fix BPF verifier's iterator convergence logic to use exact states
   comparison for convergence checks, from Eduard Zingerman,
   Andrii Nakryiko and Alexei Starovoitov.

3) Add BPF programmable net device where bpf_mprog defines the logic
   of its xmit routine. It can operate in L3 and L2 mode,
   from Daniel Borkmann and Nikolay Aleksandrov.

4) Batch of fixes for BPF per-CPU kptr and re-enable unit_size checking
   for global per-CPU allocator, from Hou Tao.

5) Fix libbpf which eagerly assumed that SHT_GNU_verdef ELF section
   was going to be present whenever a binary has SHT_GNU_versym section,
   from Andrii Nakryiko.

6) Fix BPF ringbuf correctness to fold smp_mb__before_atomic() into
   atomic_set_release(), from Paul E. McKenney.

7) Add a warning if NAPI callback missed xdp_do_flush() under
   CONFIG_DEBUG_NET which helps checking if drivers were missing
   the former, from Sebastian Andrzej Siewior.

8) Fix missed RCU read-lock in bpf_task_under_cgroup() which was throwing
   a warning under sleepable programs, from Yafang Shao.

9) Avoid unnecessary -EBUSY from htab_lock_bucket by disabling IRQ before
   checking map_locked, from Song Liu.

10) Make BPF CI linked_list failure test more robust,
    from Kumar Kartikeya Dwivedi.

11) Enable samples/bpf to be built as PIE in Fedora, from Viktor Malik.

12) Fix xsk starving when multiple xsk sockets were associated with
    a single xsk_buff_pool, from Albert Huang.

13) Clarify the signed modulo implementation for the BPF ISA standardization
    document that it uses truncated division, from Dave Thaler.

14) Improve BPF verifier's JEQ/JNE branch taken logic to also consider
    signed bounds knowledge, from Andrii Nakryiko.

15) Add an option to XDP selftests to use multi-buffer AF_XDP
    xdp_hw_metadata and mark used XDP programs as capable to use frags,
    from Larysa Zaremba.

16) Fix bpftool's BTF dumper wrt printing a pointer value and another
    one to fix struct_ops dump in an array, from Manu Bretelle.

* tag 'for-netdev' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (51 commits)
  netkit: Remove explicit active/peer ptr initialization
  selftests/bpf: Fix selftests broken by mitigations=off
  samples/bpf: Allow building with custom bpftool
  samples/bpf: Fix passing LDFLAGS to libbpf
  samples/bpf: Allow building with custom CFLAGS/LDFLAGS
  bpf: Add more WARN_ON_ONCE checks for mismatched alloc and free
  selftests/bpf: Add selftests for netkit
  selftests/bpf: Add netlink helper library
  bpftool: Extend net dump with netkit progs
  bpftool: Implement link show support for netkit
  libbpf: Add link-based API for netkit
  tools: Sync if_link uapi header
  netkit, bpf: Add bpf programmable net device
  bpf: Improve JEQ/JNE branch taken logic
  bpf: Fold smp_mb__before_atomic() into atomic_set_release()
  bpf: Fix unnecessary -EBUSY from htab_lock_bucket
  xsk: Avoid starving the xsk further down the list
  bpf: print full verifier states on infinite loop detection
  selftests/bpf: test if state loops are detected in a tricky case
  bpf: correct loop detection for iterators convergence
  ...
====================

Link: https://lore.kernel.org/r/20231026150509.2824-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-10-26 20:02:41 -07:00
Chuyi Zhou
6da8830681 cgroup: Prepare for using css_task_iter_*() in BPF
This patch makes some preparations for using css_task_iter_*() in BPF
Program.

1. Flags CSS_TASK_ITER_* are #define-s and it's not easy for bpf prog to
use them. Convert them to enum so bpf prog can take them from vmlinux.h.

2. In the next patch we will add css_task_iter_*() in common kfuncs which
is not safe. Since css_task_iter_*() does spin_unlock_irq() which might
screw up irq flags depending on the context where bpf prog is running.
So we should use irqsave/irqrestore here and the switching is harmless.

Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20231018061746.111364-2-zhouchuyi@bytedance.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-10-19 17:02:46 -07:00
Nhat Pham
8cba9576df hugetlb: memcg: account hugetlb-backed memory in memory controller
Currently, hugetlb memory usage is not acounted for in the memory
controller, which could lead to memory overprotection for cgroups with
hugetlb-backed memory.  This has been observed in our production system.

For instance, here is one of our usecases: suppose there are two 32G
containers.  The machine is booted with hugetlb_cma=6G, and each container
may or may not use up to 3 gigantic page, depending on the workload within
it.  The rest is anon, cache, slab, etc.  We can set the hugetlb cgroup
limit of each cgroup to 3G to enforce hugetlb fairness.  But it is very
difficult to configure memory.max to keep overall consumption, including
anon, cache, slab etc.  fair.

What we have had to resort to is to constantly poll hugetlb usage and
readjust memory.max.  Similar procedure is done to other memory limits
(memory.low for e.g).  However, this is rather cumbersome and buggy. 
Furthermore, when there is a delay in memory limits correction, (for e.g
when hugetlb usage changes within consecutive runs of the userspace
agent), the system could be in an over/underprotected state.

This patch rectifies this issue by charging the memcg when the hugetlb
folio is utilized, and uncharging when the folio is freed (analogous to
the hugetlb controller).  Note that we do not charge when the folio is
allocated to the hugetlb pool, because at this point it is not owned by
any memcg.

Some caveats to consider:
  * This feature is only available on cgroup v2.
  * There is no hugetlb pool management involved in the memory
    controller. As stated above, hugetlb folios are only charged towards
    the memory controller when it is used. Host overcommit management
    has to consider it when configuring hard limits.
  * Failure to charge towards the memcg results in SIGBUS. This could
    happen even if the hugetlb pool still has pages (but the cgroup
    limit is hit and reclaim attempt fails).
  * When this feature is enabled, hugetlb pages contribute to memory
    reclaim protection. low, min limits tuning must take into account
    hugetlb memory.
  * Hugetlb pages utilized while this option is not selected will not
    be tracked by the memory controller (even if cgroup v2 is remounted
    later on).

Link: https://lkml.kernel.org/r/20231006184629.155543-4-nphamcs@gmail.com
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Frank van der Linden <fvdl@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Tejun heo <tj@kernel.org>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-10-18 14:34:17 -07:00
Kamalesh Babulal
27a6c5c50c cgroup: use legacy_name for cgroup v1 disable info
cgroup v1 or v2 or both controller names can be passed as arguments to
the 'cgroup_no_v1' kernel parameter, though most of the controller's
names are the same for both cgroup versions. This can be confusing when
both versions are used interchangeably, i.e., passing cgroup_no_v1=io

$ sudo dmesg |grep cgroup
...
cgroup: Disabling io control group subsystem in v1 mounts
cgroup: Disabled controller 'blkio'

Make it consistent across the pr_info()'s, by using ss->legacy_name, as
the subsystem name, while printing the cgroup v1 controller disabling
information in cgroup_init().

Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-10-09 06:46:56 -10:00
Michal Koutný
1ca0b60515 cgroup: Remove duplicates in cgroup v1 tasks file
One PID may appear multiple times in a preloaded pidlist.
(Possibly due to PID recycling but we have reports of the same
task_struct appearing with different PIDs, thus possibly involving
transfer of PID via de_thread().)

Because v1 seq_file iterator uses PIDs as position, it leads to
a message:
> seq_file: buggy .next function kernfs_seq_next did not update position index

Conservative and quick fix consists of removing duplicates from `tasks`
file (as opposed to removing pidlists altogether). It doesn't affect
correctness (it's sufficient to show a PID once), performance impact
would be hidden by unconditional sorting of the pidlist already in place
(asymptotically).

Link: https://lore.kernel.org/r/20230823174804.23632-1-mkoutny@suse.com/
Suggested-by: Firo Yang <firo.yang@suse.com>
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
2023-10-09 06:42:05 -10:00
Harshit Mogalapalli
783a8334ec cgroup/cpuset: Cleanup signedness issue in cpu_exclusive_check()
Smatch complains about returning negative error codes from a type
bool function.

kernel/cgroup/cpuset.c:705 cpu_exclusive_check() warn:
	signedness bug returning '(-22)'

The code works correctly, but it is confusing.  The current behavior is
that cpu_exclusive_check() returns true if it's *NOT* exclusive.  Rename
it to cpusets_are_exclusive() and reverse the returns so it returns true
if it is exclusive and false if it's not.  Update both callers as well.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Closes: https://lore.kernel.org/r/202309201706.2LhKdM6o-lkp@intel.com/
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Reviewed-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-10-04 08:58:33 -10:00
Waiman Long
46c521bac5 cgroup/cpuset: Enable invalid to valid local partition transition
When a local partition becomes invalid, it won't transition back to
valid partition automatically if a proper "cpuset.cpus.exclusive" or
"cpuset.cpus" change is made. Instead, system administrators have to
explicitly echo "root" or "isolated" into the "cpuset.cpus.partition"
file at the partition root.

This patch now enables the automatic transition of an invalid local
partition back to valid when there is a proper "cpuset.cpus.exclusive"
or "cpuset.cpus" change.

Automatic transition of an invalid remote partition to a valid one,
however, is not covered by this patch. They still need an explicit
write to "cpuset.cpus.partition" to become valid again.

The test_cpuset_prs.sh test script is updated to add new test cases to
test this automatic state transition.

Reported-by: Pierre Gondois <pierre.gondois@arm.com>
Link: https://lore.kernel.org/lkml/9777f0d2-2fdf-41cb-bd01-19c52939ef42@arm.com
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-10-04 08:54:40 -10:00
Luiz Capitulino
9b81d3a5be cgroup: add cgroup_favordynmods= command-line option
We have a need of using favordynmods with cgroup v1, which doesn't support
changing mount flags during remount. Enabling CONFIG_CGROUP_FAVOR_DYNMODS at
build-time is not an option because we want to be able to selectively
enable it for certain systems.

This commit addresses this by introducing the cgroup_favordynmods=
command-line option. This option works for both cgroup v1 and v2 and also
allows for disabling favorynmods when the kernel built with
CONFIG_CGROUP_FAVOR_DYNMODS=y.

Also, note that when cgroup_favordynmods=true favordynmods is never
disabled in cgroup_destroy_root().

Signed-off-by: Luiz Capitulino <luizcap@amazon.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-10-04 08:47:55 -10:00
Waiman Long
4a74e41888 cgroup/cpuset: Check partition conflict with housekeeping setup
A user can pre-configure certain CPUs in an isolated state at boot time
with the "isolcpus" kernel boot command line option. Those CPUs will
not be in the housekeeping_cpumask(HK_TYPE_DOMAIN) and so will not
be in any sched domains. This may conflict with the partition setup
at runtime. Those boot time isolated CPUs should only be used in an
isolated partition.

This patch adds the necessary check and disallows partition setup if the
check fails.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-09-18 10:32:31 -10:00
Waiman Long
181c8e091a cgroup/cpuset: Introduce remote partition
One can use "cpuset.cpus.partition" to create multiple scheduling domains
or to produce a set of isolated CPUs where load balancing is disabled.
The former use case is less common but the latter one can be frequently
used especially for the Telco use cases like DPDK.

The existing "isolated" partition can be used to produce isolated
CPUs if the applications have full control of a system. However, in a
containerized environment where all the apps are run in a container,
it is hard to distribute out isolated CPUs from the root down given
the unified hierarchy nature of cgroup v2.

The container running on isolated CPUs can be several layers down from
the root. The current partition feature requires that all the ancestors
of a leaf partition root must be parititon roots themselves. This can
be hard to configure.

This patch introduces a new type of partition called remote partition.
A remote partition is a partition whose parent is not a partition root
itself and its CPUs are acquired directly from available CPUs in the
top cpuset through a hierachical distribution of exclusive CPUs down
from it.

By contrast, the existing type of partitions where their parents have
to be valid partition roots are referred to as local partitions as they
have to be clustered around a parent partition root.

Child local partitons can be created under a remote partition, but
a remote partition cannot be created under a local partition. We may
relax this limitation in the future if there are use cases for such
configuration.

Manually writing to the "cpuset.cpus.exclusive" file is not necessary
when creating local partitions.  However, writing proper values to
"cpuset.cpus.exclusive" down the cgroup hierarchy before the target
remote partition root is mandatory for the creation of a remote
partition.

The value in "cpuset.cpus.exclusive.effective" may change if its
"cpuset.cpus" or its parent's "cpuset.cpus.exclusive.effective" changes.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-09-18 10:32:31 -10:00
Waiman Long
e2ffe502ba cgroup/cpuset: Add cpuset.cpus.exclusive for v2
This patch introduces a new writable "cpuset.cpus.exclusive" control
file for v2 which will be added to non-root cpuset enabled cgroups. This new
file enables user to set a smaller list of exclusive CPUs to be used in
the creation of a cpuset partition.

The value written to "cpuset.cpus.exclusive" may not be the effective
value being used for the creation of cpuset partition, the effective
value will show up in "cpuset.cpus.exclusive.effective" and it is
subject to the constraint that it must also be a subset of cpus_allowed
and parent's "cpuset.cpus.exclusive.effective".

By writing to "cpuset.cpus.exclusive", "cpuset.cpus.exclusive.effective"
may be set to a non-empty value even for cgroups that are not valid
partition roots yet.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-09-18 10:32:31 -10:00
Waiman Long
0c7f293efc cgroup/cpuset: Add cpuset.cpus.exclusive.effective for v2
The creation of a cpuset partition means dedicating a set of exclusive
CPUs to be used by a particular partition only. These exclusive CPUs
will not be used by any cpusets outside of that partition.

To enable more flexibility in creating partitions, we need a way to
distribute exclusive CPUs that can be used in new partitions. Currently,
we have a subparts_cpus cpumask in struct cpuset that tracks only
the exclusive CPUs used by all the sub-partitions underneath a given
cpuset.

This patch reworks the way we do exclusive CPUs tracking. The
subparts_cpus is now renamed to effective_xcpus which tracks the
exclusive CPUs allocated to a partition root including those that are
further distributed down to sub-partitions underneath it. IOW, it also
includes the exclusive CPUs used by the current partition root. Note
that effective_xcpus can contain offline CPUs and it will always be a
subset of cpus_allowed.

The renamed effective_xcpus is now exposed via a new read-only
"cpuset.cpus.exclusive.effective" control file. The new effective_xcpus
cpumask should be set to cpus_allowed when a cpuset becomes a partition
root and be cleared if it is not a valid partition root.

In the next patch, we will enable write to another new control file to
enable further control of what can get into effective_xcpus.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-09-18 10:32:31 -10:00
Waiman Long
6fcdb0183b cgroup/cpuset: Fix load balance state in update_partition_sd_lb()
Commit a86ce68078 ("cgroup/cpuset: Extract out CS_CPU_EXCLUSIVE
& CS_SCHED_LOAD_BALANCE handling") adds a new helper function
update_partition_sd_lb() to update the load balance state of the
cpuset. However the new load balance is determined by just looking at
whether the cpuset is a valid isolated partition root or not.  That is
not enough if the cpuset is not a valid partition root but its parent
is in the isolated state (load balance off). Update the function to
set the new state to be the same as its parent in this case like what
has been done in commit c8c926200c ("cgroup/cpuset: Inherit parent's
load balance state in v2").

Fixes: a86ce68078 ("cgroup/cpuset: Extract out CS_CPU_EXCLUSIVE & CS_SCHED_LOAD_BALANCE handling")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-09-18 10:32:30 -10:00
Kamalesh Babulal
d24f05987c cgroup: Avoid extra dereference in css_populate_dir()
Use css directly instead of dereferencing it from &cgroup->self, while
adding the cgroup v2 cft base and psi files in css_populate_dir(). Both
points to the same css, when css->ss is NULL, this avoids extra deferences
and makes code consistent in usage across the function.

Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-09-18 08:58:27 -10:00
Kamalesh Babulal
fd55c0adb4 cgroup: Check for ret during cgroup1_base_files cft addition
There is no check for possible failure while populating
cgroup1_base_files cft in css_populate_dir(), like its cgroup v2 counter
parts cgroup_{base,psi}_files.  In case of failure, the cgroup might not
be set up right.  Add ret value check to return on failure.

Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-09-18 08:57:22 -10:00
Linus Torvalds
76be05d4fd cgroup: fix build when CGROUP_SCHED is not enabled
Sudip Mukherjee reports that the mips sb1250_swarm_defconfig build fails
with the current kernel.  It isn't actually MIPS-specific, it's just
that that defconfig does not have CGROUP_SCHED enabled like most configs
do, and as such shows this error:

  kernel/cgroup/cgroup.c: In function 'cgroup_local_stat_show':
  kernel/cgroup/cgroup.c:3699:15: error: implicit declaration of function 'cgroup_tryget_css'; did you mean 'cgroup_tryget'? [-Werror=implicit-function-declaration]
   3699 |         css = cgroup_tryget_css(cgrp, ss);
        |               ^~~~~~~~~~~~~~~~~
        |               cgroup_tryget
  kernel/cgroup/cgroup.c:3699:13: warning: assignment to 'struct cgroup_subsys_state *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
   3699 |         css = cgroup_tryget_css(cgrp, ss);
        |             ^

because cgroup_tryget_css() only exists when CGROUP_SCHED is enabled,
and the cgroup_local_stat_show() function should similarly be guarded by
that config option.

Move things around a bit to fix this all.

Fixes: d1d4ff5d11 ("cgroup: put cgroup_tryget_css() inside CONFIG_CGROUP_SCHED")
Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2023-09-02 08:27:17 -07:00
Linus Torvalds
7716f383a5 cgroup: Changes for v6.6
* Per-cpu cpu usage stats are now tracked. This currently isn't printed out
   in the cgroupfs interface and can only be accessed through e.g. BPF.
   Should decide on a not-too-ugly way to show per-cpu stats in cgroupfs.
 
 * cpuset received some cleanups and prepatory patches for the pending
   cpus.exclusive patchset which will allow cpuset partitions to be created
   below non-partition parents, which should ease the management of partition
   cpusets.
 
 * A lot of code and documentation cleanup patches.
 
 * tools/testing/selftests/cgroup/test_cpuset.c is added. This causes trivial
   conflicts in .gitignore and Makefile under the directory against
   fe3b1bf19b ("selftests: cgroup: add test_zswap program"). They can be
   resolved by keeping lines from both branches.
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Merge tag 'cgroup-for-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup updates from Tejun Heo:

 - Per-cpu cpu usage stats are now tracked

   This currently isn't printed out in the cgroupfs interface and can
   only be accessed through e.g. BPF. Should decide on a not-too-ugly
   way to show per-cpu stats in cgroupfs

 - cpuset received some cleanups and prepatory patches for the pending
   cpus.exclusive patchset which will allow cpuset partitions to be
   created below non-partition parents, which should ease the management
   of partition cpusets

 - A lot of code and documentation cleanup patches

 - tools/testing/selftests/cgroup/test_cpuset.c added

* tag 'cgroup-for-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (32 commits)
  cgroup: Avoid -Wstringop-overflow warnings
  cgroup:namespace: Remove unused cgroup_namespaces_init()
  cgroup/rstat: Record the cumulative per-cpu time of cgroup and its descendants
  cgroup: clean up if condition in cgroup_pidlist_start()
  cgroup: fix obsolete function name in cgroup_destroy_locked()
  Documentation: cgroup-v2.rst: Correct number of stats entries
  cgroup: fix obsolete function name above css_free_rwork_fn()
  cgroup/cpuset: fix kernel-doc
  cgroup: clean up printk()
  cgroup: fix obsolete comment above cgroup_create()
  docs: cgroup-v1: fix typo
  docs: cgroup-v1: correct the term of Page Cache organization in inode
  cgroup/misc: Store atomic64_t reads to u64
  cgroup/misc: Change counters to be explicit 64bit types
  cgroup/misc: update struct members descriptions
  cgroup: remove cgrp->kn check in css_populate_dir()
  cgroup: fix obsolete function name
  cgroup: use cached local variable parent in for loop
  cgroup: remove obsolete comment above struct cgroupstats
  cgroup: put cgroup_tryget_css() inside CONFIG_CGROUP_SCHED
  ...
2023-09-01 15:58:21 -07:00
Gustavo A. R. Silva
78d44b824e cgroup: Avoid -Wstringop-overflow warnings
Change the notation from pointer-to-array to pointer-to-pointer.
With this, we avoid the compiler complaining about trying
to access a region of size zero as an argument during function
calls.

This is a workaround to prevent the compiler complaining about
accessing an array of size zero when evaluating the arguments
of a couple of function calls. See below:

kernel/cgroup/cgroup.c: In function 'find_css_set':
kernel/cgroup/cgroup.c:1206:16: warning: 'find_existing_css_set' accessing 4 bytes in a region of size 0 [-Wstringop-overflow=]
 1206 |         cset = find_existing_css_set(old_cset, cgrp, template);
      |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
kernel/cgroup/cgroup.c:1206:16: note: referencing argument 3 of type 'struct cgroup_subsys_state *[0]'
kernel/cgroup/cgroup.c:1071:24: note: in a call to function 'find_existing_css_set'
 1071 | static struct css_set *find_existing_css_set(struct css_set *old_cset,
      |                        ^~~~~~~~~~~~~~~~~~~~~

With the change to pointer-to-pointer, the functions are not prevented
from being executed, and they will do what they have to do when
CGROUP_SUBSYS_COUNT == 0.

Address the following -Wstringop-overflow warnings seen when
built with ARM architecture and aspeed_g4_defconfig configuration
(notice that under this configuration CGROUP_SUBSYS_COUNT == 0):

kernel/cgroup/cgroup.c:1208:16: warning: 'find_existing_css_set' accessing 4 bytes in a region of size 0 [-Wstringop-overflow=]
kernel/cgroup/cgroup.c:1258:15: warning: 'css_set_hash' accessing 4 bytes in a region of size 0 [-Wstringop-overflow=]
kernel/cgroup/cgroup.c:6089:18: warning: 'css_set_hash' accessing 4 bytes in a region of size 0 [-Wstringop-overflow=]
kernel/cgroup/cgroup.c:6153:18: warning: 'css_set_hash' accessing 4 bytes in a region of size 0 [-Wstringop-overflow=]

This results in no differences in binary output.

Link: https://github.com/KSPP/linux/issues/316
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-08-17 11:55:05 -10:00
Lu Jialin
82b90b6c5b cgroup:namespace: Remove unused cgroup_namespaces_init()
cgroup_namspace_init() just return 0. Therefore, there is no need to
call it during start_kernel. Just remove it.

Fixes: a79a908fd2 ("cgroup: introduce cgroup namespaces")
Signed-off-by: Lu Jialin <lujialin4@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-08-14 14:29:47 -10:00
Hao Jia
0437719c1a cgroup/rstat: Record the cumulative per-cpu time of cgroup and its descendants
The member variable bstat of the structure cgroup_rstat_cpu
records the per-cpu time of the cgroup itself, but does not
include the per-cpu time of its descendants. The per-cpu time
including descendants is very useful for calculating the
per-cpu usage of cgroups.

Although we can indirectly obtain the total per-cpu time
of the cgroup and its descendants by accumulating the per-cpu
bstat of each descendant of the cgroup. But after a child cgroup
is removed, we will lose its bstat information. This will cause
the cumulative value to be non-monotonic, thus affecting
the accuracy of cgroup per-cpu usage.

So we add the subtree_bstat variable to record the total
per-cpu time of this cgroup and its descendants, which is
similar to "cpuacct.usage*" in cgroup v1. And this is
also helpful for the migration from cgroup v1 to cgroup v2.
After adding this variable, we can obtain the per-cpu time of
cgroup and its descendants in user mode through eBPF/drgn, etc.
And we are still trying to determine how to expose it in the
cgroupfs interface.

Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Hao Jia <jiahao.os@bytedance.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-08-07 08:41:25 -10:00
Miaohe Lin
e7e64a1bff cgroup: clean up if condition in cgroup_pidlist_start()
There's no need to use '<=' when knowing 'l->list[mid] != pid' already.
No functional change intended.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-08-07 08:30:06 -10:00
Miaohe Lin
7f828eacc4 cgroup: fix obsolete function name in cgroup_destroy_locked()
Since commit e76ecaeef6 ("cgroup: use cgroup_kn_lock_live() in other
cgroup kernfs methods"), cgroup_kn_lock_live() is used in cgroup kernfs
methods. Update corresponding comment.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-08-03 14:13:33 -10:00
Miaohe Lin
a2c15fece4 cgroup: fix obsolete function name above css_free_rwork_fn()
Since commit 8f36aaec9c ("cgroup: Use rcu_work instead of explicit rcu
and work item"), css_free_work_fn has been renamed to css_free_rwork_fn.
Update corresponding comment.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-08-02 09:37:59 -10:00
Cai Xinchen
05f76ae95e cgroup/cpuset: fix kernel-doc
Add kernel-doc of param @rotor to fix warnings:

kernel/cgroup/cpuset.c:4162: warning: Function parameter or member
'rotor' not described in 'cpuset_spread_node'
kernel/cgroup/cpuset.c:3771: warning: Function parameter or member
'work' not described in 'cpuset_hotplug_workfn'

Signed-off-by: Cai Xinchen <caixinchen1@huawei.com>
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-08-02 09:37:03 -10:00
Kamalesh Babulal
55a5956a55 cgroup: clean up printk()
Convert the only printk() to use pr_*() helper. No functional change.

Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-08-02 09:36:24 -10:00
Miaohe Lin
a3fdeeb3f1 cgroup: fix obsolete comment above cgroup_create()
Since commit 743210386c ("cgroup: use cgrp->kn->id as the cgroup ID"),
cgrp is associated with its kernfs_node. Update corresponding comment.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-07-21 09:54:48 -10:00
Haitao Huang
714e08cc3e cgroup/misc: Store atomic64_t reads to u64
Change 'new_usage' type to u64 so it can be compared with unsigned 'max'
and 'capacity' properly even if the value crosses the signed boundary.

Signed-off-by: Haitao Huang <haitao.huang@linux.intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-07-21 08:10:06 -10:00
Ingo Molnar
752182b24b Linux 6.5-rc2
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Merge tag 'v6.5-rc2' into sched/core, to pick up fixes

Sync with upstream fixes before applying EEVDF.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2023-07-19 09:43:25 +02:00
Haitao Huang
32bf85c60c cgroup/misc: Change counters to be explicit 64bit types
So the variables can account for resources of huge quantities even on
32-bit machines.

Signed-off-by: Haitao Huang <haitao.huang@linux.intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-07-18 12:10:00 -10:00
Kamalesh Babulal
c25ff4b911 cgroup: remove cgrp->kn check in css_populate_dir()
cgroup_create() creates cgrp and assigns the kernfs_node to cgrp->kn,
then cgroup_mkdir() populates base and csses cft file by calling
css_populate_dir() and cgroup_apply_control_enable() with a valid
cgrp->kn. Check for NULL cgrp->kn, will always be false, remove it.

Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-07-17 08:44:56 -10:00
Miaohe Lin
6f71780e7f cgroup: fix obsolete function name
cgroup_taskset_migrate() has been renamed to cgroup_migrate_execute() since
commit e595cd7069 ("cgroup: track migration context in cgroup_mgctx").
Update the corresponding comment.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-07-17 08:38:58 -10:00
Miaohe Lin
fcbb485d9f cgroup: use cached local variable parent in for loop
Use local variable parent to initialize iter tcgrp in for loop so the size
of cgroup.o can be reduced by 64 bytes. No functional change intended.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-07-17 08:34:41 -10:00
Josh Don
677ea015f2 sched: add throttled time stat for throttled children
We currently export the total throttled time for cgroups that are given
a bandwidth limit. This patch extends this accounting to also account
the total time that each children cgroup has been throttled.

This is useful to understand the degree to which children have been
affected by the throttling control. Children which are not runnable
during the entire throttled period, for example, will not show any
self-throttling time during this period.

Expose this in a new interface, 'cpu.stat.local', which is similar to
how non-hierarchical events are accounted in 'memory.events.local'.

Signed-off-by: Josh Don <joshdon@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20230620183247.737942-2-joshdon@google.com
2023-07-13 15:21:49 +02:00
Miaohe Lin
d1d4ff5d11 cgroup: put cgroup_tryget_css() inside CONFIG_CGROUP_SCHED
Put cgroup_tryget_css() inside CONFIG_CGROUP_SCHED to fix the warning
of 'cgroup_tryget_css' defined but not used [-Wunused-function] when
CONFIG_CGROUP_SCHED is disabled.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-07-11 11:46:00 -10:00
Waiman Long
3ae0b77321 cgroup/cpuset: Allow suppression of sched domain rebuild in update_cpumasks_hier()
A single partition setup and tear-down operation can lead to
multiple rebuild_sched_domains_locked() calls which is a waste of
effort. This can partly be mitigated by adding a flag to suppress the
rebuild_sched_domains_locked() call in update_cpumasks_hier(). Since
a Boolean flag has already been passed as the 3rd argument to
update_cpumasks_hier(), we can extend that to a full flag word.

The sched domain rebuild suppression is now enabled in
update_sibling_cpumasks() as all it callers will do the sched domain
rebuild after its return later on anyway.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-07-10 11:01:23 -10:00
Waiman Long
99fe36ba6f cgroup/cpuset: Improve temporary cpumasks handling
The limitation that update_parent_subparts_cpumask() can only use
addmask & delmask in the given tmp cpumasks is fragile and may lead to
unexpected error.

Fix this problem by allocating/freeing a struct tmpmasks in
update_cpumask() to avoid reusing the cpumasks in trial_cs.

With this change, we can move the update_tasks_cpumask() for the
parent and update_sibling_cpumasks() for the sibling to inside
update_parent_subparts_cpumask().

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-07-10 11:01:03 -10:00
Waiman Long
a86ce68078 cgroup/cpuset: Extract out CS_CPU_EXCLUSIVE & CS_SCHED_LOAD_BALANCE handling
Extract out the setting of CS_CPU_EXCLUSIVE and CS_SCHED_LOAD_BALANCE
flags as well as the rebuilding of scheduling domains into the new
update_partition_exclusive() and update_partition_sd_lb() helper
functions to simplify the logic. The update_partition_exclusive()
helper is called mainly at the beginning of the caller, but it may be
called at the end too. The update_partition_sd_lb() helper is called
at the end of the caller.

This patch should reduce the chance that cpuset partition will end up
in an incorrect state.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-07-10 11:00:12 -10:00
Waiman Long
c8c926200c cgroup/cpuset: Inherit parent's load balance state in v2
Since commit f28e22441f ("cgroup/cpuset: Add a new isolated
cpus.partition type"), the CS_SCHED_LOAD_BALANCE bit of a v2 cpuset
can be on or off. The child cpusets of a partition root must have the
same setting as its parent or it may screw up the rebuilding of sched
domains. Fix this problem by making sure the a child v2 cpuset will
follows its parent cpuset load balance state unless the child cpuset
is a new partition root itself.

Fixes: f28e22441f ("cgroup/cpuset: Add a new isolated cpus.partition type")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-07-10 10:59:27 -10:00
Miaohe Lin
868f87b375 cgroup: fix obsolete comment above for_each_css()
cgroup_tree_mutex is removed since commit 8353da1f91 ("cgroup: remove
cgroup_tree_mutex"), update corresponding comment.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-07-10 10:47:25 -10:00
Michal Koutný
0a67b847e1 cpuset: Allow setscheduler regardless of manipulated task
When we migrate a task between two cgroups, one of the checks is a
verification whether we can modify task's scheduler settings
(cap_task_setscheduler()).

An implicit migration occurs also when enabling a controller on the
unified hierarchy (think of parent to child migration). The
aforementioned check may be problematic if the caller of the migration
(enabling a controller) has no permissions over migrated tasks.
For instance, a user's cgroup that ends up running a process of a
different user. Although cgroup permissions are configured favorably,
the enablement fails due to the foreign process [1].

Change the behavior by relaxing the permissions check on the unified
hierarchy when no effective change would happen.
This is in accordance with unified hierarchy attachment behavior when
permissions of the source to target cgroups are decisive whereas the
migrated task is opaque (as opposed to more restrictive check in
__cgroup1_procs_write()).

Notice that foreign task's affinity may still be modified if the user
can modify destination cgroup's cpuset attributes
(update_tasks_cpumask() does no permissions check). The permissions
check could thus be skipped on v2 even when affinity changes. Stay
conservative in this patch though.

[1] https://github.com/systemd/systemd/issues/18293#issuecomment-831205649

Signed-off-by: Michal Koutný <mkoutny@suse.com>
Reviewed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-07-10 10:28:43 -10:00
Miaohe Lin
48f074565b cgroup/cpuset: avoid unneeded cpuset_mutex re-lock
cpuset_mutex unlock and lock pair is only needed when transferring tasks
out of empty cpuset. Avoid unneeded cpuset_mutex re-lock when !is_empty
to save cpu cycles.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2023-07-10 10:26:06 -10:00