mirror of https://github.com/torvalds/linux.git
1043 Commits
| Author | SHA1 | Message | Date |
|---|---|---|---|
Jason A. Donenfeld
|
81895a65ec |
treewide: use prandom_u32_max() when possible, part 1
Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions. This was
done mechanically with this coccinelle script:
@basic@
expression E;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u64;
@@
(
- ((T)get_random_u32() % (E))
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ((E) - 1))
+ prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2)
|
- ((u64)(E) * get_random_u32() >> 32)
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ~PAGE_MASK)
+ prandom_u32_max(PAGE_SIZE)
)
@multi_line@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
identifier RAND;
expression E;
@@
- RAND = get_random_u32();
... when != RAND
- RAND %= (E);
+ RAND = prandom_u32_max(E);
// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@
((T)get_random_u32()@p & (LITERAL))
// Add one to the literal.
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@
value = None
if literal.startswith('0x'):
value = int(literal, 16)
elif literal[0] in '123456789':
value = int(literal, 10)
if value is None:
print("I don't know how to handle %s" % (literal))
cocci.include_match(False)
elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1:
print("Skipping 0x%x for cleanup elsewhere" % (value))
cocci.include_match(False)
elif value & (value + 1) != 0:
print("Skipping 0x%x because it's not a power of two minus one" % (value))
cocci.include_match(False)
elif literal.startswith('0x'):
coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1))
else:
coccinelle.RESULT = cocci.make_expr("%d" % (value + 1))
// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
expression add_one.RESULT;
identifier FUNC;
@@
- (FUNC()@p & (LITERAL))
+ prandom_u32_max(RESULT)
@collapse_ret@
type T;
identifier VAR;
expression E;
@@
{
- T VAR;
- VAR = (E);
- return VAR;
+ return E;
}
@drop_var@
type T;
identifier VAR;
@@
{
- T VAR;
... when != VAR
}
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: KP Singh <kpsingh@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
Linus Torvalds
|
27bc50fc90 |
- Yu Zhao's Multi-Gen LRU patches are here. They've been under test in
linux-next for a couple of months without, to my knowledge, any negative reports (or any positive ones, come to that). - Also the Maple Tree from Liam R. Howlett. An overlapping range-based tree for vmas. It it apparently slight more efficient in its own right, but is mainly targeted at enabling work to reduce mmap_lock contention. Liam has identified a number of other tree users in the kernel which could be beneficially onverted to mapletrees. Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat (https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com). This has yet to be addressed due to Liam's unfortunately timed vacation. He is now back and we'll get this fixed up. - Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses clang-generated instrumentation to detect used-unintialized bugs down to the single bit level. KMSAN keeps finding bugs. New ones, as well as the legacy ones. - Yang Shi adds a userspace mechanism (madvise) to induce a collapse of memory into THPs. - Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to support file/shmem-backed pages. - userfaultfd updates from Axel Rasmussen - zsmalloc cleanups from Alexey Romanov - cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and memory-failure - Huang Ying adds enhancements to NUMA balancing memory tiering mode's page promotion, with a new way of detecting hot pages. - memcg updates from Shakeel Butt: charging optimizations and reduced memory consumption. - memcg cleanups from Kairui Song. - memcg fixes and cleanups from Johannes Weiner. - Vishal Moola provides more folio conversions - Zhang Yi removed ll_rw_block() :( - migration enhancements from Peter Xu - migration error-path bugfixes from Huang Ying - Aneesh Kumar added ability for a device driver to alter the memory tiering promotion paths. For optimizations by PMEM drivers, DRM drivers, etc. - vma merging improvements from Jakub Matěn. - NUMA hinting cleanups from David Hildenbrand. - xu xin added aditional userspace visibility into KSM merging activity. - THP & KSM code consolidation from Qi Zheng. - more folio work from Matthew Wilcox. - KASAN updates from Andrey Konovalov. - DAMON cleanups from Kaixu Xia. - DAMON work from SeongJae Park: fixes, cleanups. - hugetlb sysfs cleanups from Muchun Song. - Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core. -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCY0HaPgAKCRDdBJ7gKXxA joPjAQDZ5LlRCMWZ1oxLP2NOTp6nm63q9PWcGnmY50FjD/dNlwEAnx7OejCLWGWf bbTuk6U2+TKgJa4X7+pbbejeoqnt5QU= =xfWx -----END PGP SIGNATURE----- Merge tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in linux-next for a couple of months without, to my knowledge, any negative reports (or any positive ones, come to that). - Also the Maple Tree from Liam Howlett. An overlapping range-based tree for vmas. It it apparently slightly more efficient in its own right, but is mainly targeted at enabling work to reduce mmap_lock contention. Liam has identified a number of other tree users in the kernel which could be beneficially onverted to mapletrees. Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat at [1]. This has yet to be addressed due to Liam's unfortunately timed vacation. He is now back and we'll get this fixed up. - Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses clang-generated instrumentation to detect used-unintialized bugs down to the single bit level. KMSAN keeps finding bugs. New ones, as well as the legacy ones. - Yang Shi adds a userspace mechanism (madvise) to induce a collapse of memory into THPs. - Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to support file/shmem-backed pages. - userfaultfd updates from Axel Rasmussen - zsmalloc cleanups from Alexey Romanov - cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and memory-failure - Huang Ying adds enhancements to NUMA balancing memory tiering mode's page promotion, with a new way of detecting hot pages. - memcg updates from Shakeel Butt: charging optimizations and reduced memory consumption. - memcg cleanups from Kairui Song. - memcg fixes and cleanups from Johannes Weiner. - Vishal Moola provides more folio conversions - Zhang Yi removed ll_rw_block() :( - migration enhancements from Peter Xu - migration error-path bugfixes from Huang Ying - Aneesh Kumar added ability for a device driver to alter the memory tiering promotion paths. For optimizations by PMEM drivers, DRM drivers, etc. - vma merging improvements from Jakub Matěn. - NUMA hinting cleanups from David Hildenbrand. - xu xin added aditional userspace visibility into KSM merging activity. - THP & KSM code consolidation from Qi Zheng. - more folio work from Matthew Wilcox. - KASAN updates from Andrey Konovalov. - DAMON cleanups from Kaixu Xia. - DAMON work from SeongJae Park: fixes, cleanups. - hugetlb sysfs cleanups from Muchun Song. - Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core. Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1] * tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits) hugetlb: allocate vma lock for all sharable vmas hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer hugetlb: fix vma lock handling during split vma and range unmapping mglru: mm/vmscan.c: fix imprecise comments mm/mglru: don't sync disk for each aging cycle mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol mm: memcontrol: use do_memsw_account() in a few more places mm: memcontrol: deprecate swapaccounting=0 mode mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled mm/secretmem: remove reduntant return value mm/hugetlb: add available_huge_pages() func mm: remove unused inline functions from include/linux/mm_inline.h selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd selftests/vm: add thp collapse shmem testing selftests/vm: add thp collapse file and tmpfs testing selftests/vm: modularize thp collapse memory operations selftests/vm: dedup THP helpers mm/khugepaged: add tracepoint to hpage_collapse_scan_file() mm/madvise: add file and shmem support to MADV_COLLAPSE ... |
|
|
Linus Torvalds
|
3e71f0167b |
Locking changes for v6.1:
- Disable preemption in rwsem_write_trylock()'s attempt to
take the rwsem, to avoid RT tasks hogging the CPU, which
managed to preempt this function after the owner has
been cleared but before a new owner is set. Also add
debug checks to enforce this.
- Add __lockfunc to more slow path functions and add
__sched to semaphore functions.
- Mark spinlock APIs noinline when the respective CONFIG_INLINE_SPIN_*
toggles are disabled, to reduce LTO text size.
- Print more debug information when lockdep gets confused
in look_up_lock_class().
- Improve header file abuse checks.
- Misc cleanups
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'locking-core-2022-10-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
- Disable preemption in rwsem_write_trylock()'s attempt to take the
rwsem, to avoid RT tasks hogging the CPU, which managed to preempt
this function after the owner has been cleared but before a new owner
is set. Also add debug checks to enforce this.
- Add __lockfunc to more slow path functions and add __sched to
semaphore functions.
- Mark spinlock APIs noinline when the respective CONFIG_INLINE_SPIN_*
toggles are disabled, to reduce LTO text size.
- Print more debug information when lockdep gets confused in
look_up_lock_class().
- Improve header file abuse checks.
- Misc cleanups
* tag 'locking-core-2022-10-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/lockdep: Print more debug information - report name and key when look_up_lock_class() got confused
locking: Add __sched to semaphore functions
locking/rwsem: Disable preemption while trying for rwsem lock
locking: Detect includes rwlock.h outside of spinlock.h
locking: Add __lockfunc to slow path functions
locking/spinlocks: Mark spinlocks noinline when inline spinlocks are disabled
selftests: futex: Fix 'the the' typo in comment
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Alexander Potapenko
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79dbd006a6 |
kmsan: disable instrumentation of unsupported common kernel code
EFI stub cannot be linked with KMSAN runtime, so we disable instrumentation for it. Instrumenting kcov, stackdepot or lockdep leads to infinite recursion caused by instrumentation hooks calling instrumented code again. Link: https://lkml.kernel.org/r/20220915150417.722975-13-glider@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Eric Biggers <ebiggers@kernel.org> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Ilya Leoshkevich <iii@linux.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
|
Tetsuo Handa
|
76e64c73db |
locking/lockdep: Print more debug information - report name and key when look_up_lock_class() got confused
Printing this information will be helpful: ------------[ cut here ]------------ Looking for class "l2tp_sock" with key l2tp_socket_class, but found a different class "slock-AF_INET6" with the same key WARNING: CPU: 1 PID: 14195 at kernel/locking/lockdep.c:940 look_up_lock_class+0xcc/0x140 Modules linked in: CPU: 1 PID: 14195 Comm: a.out Not tainted 6.0.0-rc6-dirty #863 Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 RIP: 0010:look_up_lock_class+0xcc/0x140 Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/bd99391e-f787-efe9-5ec6-3c6dc4c587b0@I-love.SAKURA.ne.jp |
|
Ingo Molnar
|
74656d03ac |
Linux 6.0-rc6
-----BEGIN PGP SIGNATURE----- iQFSBAABCAA8FiEEq68RxlopcLEwq+PEeb4+QwBBGIYFAmMngx4eHHRvcnZhbGRz QGxpbnV4LWZvdW5kYXRpb24ub3JnAAoJEHm+PkMAQRiGQ1AH/1p4oOT4iqaoTueO MaTQhyvFFcTSLL4y1qejtytNXe4ZEJHyf03jrwtYlfx8RROkZFMJh15G1uWu2deu 43XsUuSWpJ18/C7hRNl1LUazBbuQe30d09zLe7dvD64IAABU6/iQCIorxheTl4EU NXsda2egJUIbTwn2zdFSgMMJPNORxq8KHgvNY/psIEteC+lFln2l2ZXZ21JAIdBj lcTbvx6JpJC0AqX1UuO6NsN4nUnEEh110UtYF6lxQ7olkQKwRaUjQIVuWOFLz75n wDrJxPlVGbDR5zeitDaHkKqWn8LNcqHpDIuAKMxTjT0N/1/sUwHNkyGZXyy1EDJu e0+SX1c= =ITjo -----END PGP SIGNATURE----- Merge tag 'v6.0-rc6' into locking/core, to refresh the branch Signed-off-by: Ingo Molnar <mingo@kernel.org> |
|
Namhyung Kim
|
0d97db0265 |
locking: Add __sched to semaphore functions
The internal functions are marked with __sched already, let's do the same for external functions too so that we can skip them in the stack trace. Signed-off-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20220909000803.4181857-1-namhyung@kernel.org |
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Gokul krishna Krishnakumar
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48dfb5d256 |
locking/rwsem: Disable preemption while trying for rwsem lock
Make the region inside the rwsem_write_trylock non preemptible.
We observe RT task is hogging CPU when trying to acquire rwsem lock
which was acquired by a kworker task but before the rwsem owner was set.
Here is the scenario:
1. CFS task (affined to a particular CPU) takes rwsem lock.
2. CFS task gets preempted by a RT task before setting owner.
3. RT task (FIFO) is trying to acquire the lock, but spinning until
RT throttling happens for the lock as the lock was taken by CFS task.
This patch attempts to fix the above issue by disabling preemption
until owner is set for the lock. While at it also fix the issues
at the places where rwsem_{set,clear}_owner() are called.
This also adds lockdep annotation of preemption disable in
rwsem_{set,clear}_owner() on Peter Z. suggestion.
Signed-off-by: Gokul krishna Krishnakumar <quic_gokukris@quicinc.com>
Signed-off-by: Mukesh Ojha <quic_mojha@quicinc.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Link: https://lore.kernel.org/r/1662661467-24203-1-git-send-email-quic_mojha@quicinc.com
|
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Marco Elver
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01fe8a3f81 |
locking/percpu-rwsem: Add percpu_is_write_locked() and percpu_is_read_locked()
Implement simple accessors to probe percpu-rwsem's locked state: percpu_is_write_locked(), percpu_is_read_locked(). Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Ian Rogers <irogers@google.com> Link: https://lore.kernel.org/r/20220829124719.675715-11-elver@google.com |
|
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Namhyung Kim
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501f7f69bc |
locking: Add __lockfunc to slow path functions
So that we can skip the functions in the perf lock contention and other places like /proc/PID/wchan. Signed-off-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Waiman Long <longman@redhat.com> Link: https://lore.kernel.org/r/20220810220346.1919485-1-namhyung@kernel.org |
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Andi Kleen
|
9aeaf5bc4e |
locking/spinlocks: Mark spinlocks noinline when inline spinlocks are disabled
Otherwise LTO will inline them anyways and cause a large kernel text increase. Since the explicit intention here is to not inline them marking them noinline is good documentation even for the non-LTO case. Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Martin Liska <mliska@suse.cz> Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20220719110548.1544-1-jslaby@suse.cz |
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Linus Torvalds
|
7d9d077c78 |
RCU pull request for v5.20 (or whatever)
This pull request contains the following branches: doc.2022.06.21a: Documentation updates. fixes.2022.07.19a: Miscellaneous fixes. nocb.2022.07.19a: Callback-offload updates, perhaps most notably a new RCU_NOCB_CPU_DEFAULT_ALL Kconfig option that causes all CPUs to be offloaded at boot time, regardless of kernel boot parameters. This is useful to battery-powered systems such as ChromeOS and Android. In addition, a new RCU_NOCB_CPU_CB_BOOST kernel boot parameter prevents offloaded callbacks from interfering with real-time workloads and with energy-efficiency mechanisms. poll.2022.07.21a: Polled grace-period updates, perhaps most notably making these APIs account for both normal and expedited grace periods. rcu-tasks.2022.06.21a: Tasks RCU updates, perhaps most notably reducing the CPU overhead of RCU tasks trace grace periods by more than a factor of two on a system with 15,000 tasks. The reduction is expected to increase with the number of tasks, so it seems reasonable to hypothesize that a system with 150,000 tasks might see a 20-fold reduction in CPU overhead. torture.2022.06.21a: Torture-test updates. ctxt.2022.07.05a: Updates that merge RCU's dyntick-idle tracking into context tracking, thus reducing the overhead of transitioning to kernel mode from either idle or nohz_full userspace execution for kernels that track context independently of RCU. This is expected to be helpful primarily for kernels built with CONFIG_NO_HZ_FULL=y. -----BEGIN PGP SIGNATURE----- iQJHBAABCgAxFiEEbK7UrM+RBIrCoViJnr8S83LZ+4wFAmLgMcgTHHBhdWxtY2tA a2VybmVsLm9yZwAKCRCevxLzctn7jArXD/0fjbCwqpRjHVTzjMY8jN4zDkqZZD6m g8Fx27hZ4ToNFwRptyHwNezrNj14skjAJEXfdjaVw32W62ivXvf0HINvSzsTLCSq k2kWyBdXLc9CwY5p5W4smnpn5VoAScjg5PoPL59INoZ/Zziji323C7Zepl/1DYJt 0T6bPCQjo1ZQoDUCyVpSjDmAqxnderWG0MeJVt74GkLqmnYLANg0GH8c7mH4+9LL kVGlLp5nlPgNJ4FEoFdMwNU8T/ETmaVld/m2dkiawjkXjJzB2XKtBigU91DDmXz5 7DIdV4ABrxiy4kGNqtIe/jFgnKyVD7xiDpyfjd6KTeDr/rDS8u2ZH7+1iHsyz3g0 Np/tS3vcd0KR+gI/d0eXxPbgm5sKlCmKw/nU2eArpW/+4LmVXBUfHTG9Jg+LJmBc JrUh6aEdIZJZHgv/nOQBNig7GJW43IG50rjuJxAuzcxiZNEG5lUSS23ysaA9CPCL PxRWKSxIEfK3kdmvVO5IIbKTQmIBGWlcWMTcYictFSVfBgcCXpPAksGvqA5JiUkc egW+xLFo/7K+E158vSKsVqlWZcEeUbsNJ88QOlpqnRgH++I2Yv/LhK41XfJfpH+Y ALxVaDd+mAq6v+qSHNVq9wT3ozXIPy/zK1hDlMIqx40h2YvaEsH4je+521oSoN9r vX60+QNxvUBLwA== =vUNm -----END PGP SIGNATURE----- Merge tag 'rcu.2022.07.26a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu Pull RCU updates from Paul McKenney: - Documentation updates - Miscellaneous fixes - Callback-offload updates, perhaps most notably a new RCU_NOCB_CPU_DEFAULT_ALL Kconfig option that causes all CPUs to be offloaded at boot time, regardless of kernel boot parameters. This is useful to battery-powered systems such as ChromeOS and Android. In addition, a new RCU_NOCB_CPU_CB_BOOST kernel boot parameter prevents offloaded callbacks from interfering with real-time workloads and with energy-efficiency mechanisms - Polled grace-period updates, perhaps most notably making these APIs account for both normal and expedited grace periods - Tasks RCU updates, perhaps most notably reducing the CPU overhead of RCU tasks trace grace periods by more than a factor of two on a system with 15,000 tasks. The reduction is expected to increase with the number of tasks, so it seems reasonable to hypothesize that a system with 150,000 tasks might see a 20-fold reduction in CPU overhead - Torture-test updates - Updates that merge RCU's dyntick-idle tracking into context tracking, thus reducing the overhead of transitioning to kernel mode from either idle or nohz_full userspace execution for kernels that track context independently of RCU. This is expected to be helpful primarily for kernels built with CONFIG_NO_HZ_FULL=y * tag 'rcu.2022.07.26a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (98 commits) rcu: Add irqs-disabled indicator to expedited RCU CPU stall warnings rcu: Diagnose extended sync_rcu_do_polled_gp() loops rcu: Put panic_on_rcu_stall() after expedited RCU CPU stall warnings rcutorture: Test polled expedited grace-period primitives rcu: Add polled expedited grace-period primitives rcutorture: Verify that polled GP API sees synchronous grace periods rcu: Make Tiny RCU grace periods visible to polled APIs rcu: Make polled grace-period API account for expedited grace periods rcu: Switch polled grace-period APIs to ->gp_seq_polled rcu/nocb: Avoid polling when my_rdp->nocb_head_rdp list is empty rcu/nocb: Add option to opt rcuo kthreads out of RT priority rcu: Add nocb_cb_kthread check to rcu_is_callbacks_kthread() rcu/nocb: Add an option to offload all CPUs on boot rcu/nocb: Fix NOCB kthreads spawn failure with rcu_nocb_rdp_deoffload() direct call rcu/nocb: Invert rcu_state.barrier_mutex VS hotplug lock locking order rcu/nocb: Add/del rdp to iterate from rcuog itself rcu/tree: Add comment to describe GP-done condition in fqs loop rcu: Initialize first_gp_fqs at declaration in rcu_gp_fqs() rcu/kvfree: Remove useless monitor_todo flag rcu: Cleanup RCU urgency state for offline CPU ... |
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Linus Torvalds
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22a39c3d86 |
This was a fairly quiet cycle for the locking subsystem:
- lockdep: Fix a handful of the more complex lockdep_init_map_*() primitives
that can lose the lock_type & cause false reports. No such mishap was
observed in the wild.
- jump_label improvements: simplify the cross-arch support of
initial NOP patching by making it arch-specific code (used on MIPS only),
and remove the s390 initial NOP patching that was superfluous.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'locking-core-2022-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
"This was a fairly quiet cycle for the locking subsystem:
- lockdep: Fix a handful of the more complex lockdep_init_map_*()
primitives that can lose the lock_type & cause false reports. No
such mishap was observed in the wild.
- jump_label improvements: simplify the cross-arch support of initial
NOP patching by making it arch-specific code (used on MIPS only),
and remove the s390 initial NOP patching that was superfluous"
* tag 'locking-core-2022-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/lockdep: Fix lockdep_init_map_*() confusion
jump_label: make initial NOP patching the special case
jump_label: mips: move module NOP patching into arch code
jump_label: s390: avoid pointless initial NOP patching
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Waiman Long
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6eebd5fb20 |
locking/rwsem: Allow slowpath writer to ignore handoff bit if not set by first waiter
With commit |
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Frederic Weisbecker
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e67198cc05 |
context_tracking: Take idle eqs entrypoints over RCU
The RCU dynticks counter is going to be merged into the context tracking subsystem. Start with moving the idle extended quiescent states entrypoints to context tracking. For now those are dumb redirections to existing RCU calls. [ paulmck: Apply kernel test robot feedback. ] Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Nicolas Saenz Julienne <nsaenz@kernel.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com> Cc: Yu Liao <liaoyu15@huawei.com> Cc: Phil Auld <pauld@redhat.com> Cc: Paul Gortmaker<paul.gortmaker@windriver.com> Cc: Alex Belits <abelits@marvell.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com> |
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Peter Zijlstra
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eae6d58d67 |
locking/lockdep: Fix lockdep_init_map_*() confusion
Commit |
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Sebastian Andrzej Siewior
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4051a81774 |
locking/lockdep: Use sched_clock() for random numbers
Since the rewrote of prandom_u32(), in the commit mentioned below, the
function uses sleeping locks which extracing random numbers and filling
the batch.
This breaks lockdep on PREEMPT_RT because lock_pin_lock() disables
interrupts while calling __lock_pin_lock(). This can't be moved earlier
because the main user of the function (rq_pin_lock()) invokes that
function after disabling interrupts in order to acquire the lock.
The cookie does not require random numbers as its goal is to provide a
random value in order to notice unexpected "unlock + lock" sites.
Use sched_clock() to provide random numbers.
Fixes: a0103f4d86f88 ("random32: use real rng for non-deterministic randomness")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/YoNn3pTkm5+QzE5k@linutronix.de
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Linus Torvalds
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44d35720c9 |
sysctl changes for v5.19-rc1
For two kernel releases now kernel/sysctl.c has been being cleaned up slowly, since the tables were grossly long, sprinkled with tons of #ifdefs and all this caused merge conflicts with one susbystem or another. This tree was put together to help try to avoid conflicts with these cleanups going on different trees at time. So nothing exciting on this pull request, just cleanups. I actually had this sysctl-next tree up since v5.18 but I missed sending a pull request for it on time during the last merge window. And so these changes have been being soaking up on sysctl-next and so linux-next for a while. The last change was merged May 4th. Most of the compile issues were reported by 0day and fixed. To help avoid a conflict with bpf folks at Daniel Borkmann's request I merged bpf-next/pr/bpf-sysctl into sysctl-next to get the effor which moves the BPF sysctls from kernel/sysctl.c to BPF core. Possible merge conflicts and known resolutions as per linux-next: bfp: https://lkml.kernel.org/r/20220414112812.652190b5@canb.auug.org.au rcu: https://lkml.kernel.org/r/20220420153746.4790d532@canb.auug.org.au powerpc: https://lkml.kernel.org/r/20220520154055.7f964b76@canb.auug.org.au -----BEGIN PGP SIGNATURE----- iQJGBAABCgAwFiEENnNq2KuOejlQLZofziMdCjCSiKcFAmKOq8ASHG1jZ3JvZkBr ZXJuZWwub3JnAAoJEM4jHQowkoinDAkQAJVo5YVM9f74UwYp4PQhTpjxJBCjRoZD z1u9bp5rMj2ujTC8Fr7VmzKaHrb8+r1C1WvCvZtIzemYNB4lZUrHpVDYfXuXiPRB ihPmEjhlPO5PFBx6cVCpI3cu9bEhG00rLc1QXnABx/pXwNPcOTJAGZJVamZvqubk chjgZrb7N+adHPfvS55v1+zpwdeKfpp5U3zuu5qlT/nn0GS0HCVzOj5fj4oC4wtJ IqfUubo+FX50Ga58yQABWNrjaPD9Crykz5ohVazy3ElQl0hJ4VsK65ct3blqc2vz 1Bb8kPpWuv6aZ5nr1lCVE8qvF4ZIL33ySvpg5BSdWLQEDrBbSpzvJe9Yn7wgR+eq y7fhpO24+zRM82EoDMEvyxX9u1n1RsvoXRtf3ds9BGf63MUxk8a1cgjlU6vuyO2U JhDmfM1xzdKvPoY4COOnHzcAiIqzItTqKd09N5y0cahmYstROU8lvp9huhTAHqk1 SjQMbLIZG7OnX8ZeQcR1EB8sq/IOPZT48ejj0iJmQ8FyMaep71MOQLYyLPAq4lgh JHXm8P6QdB57jfJbqAeNSyZoK0qdxOUR/83Zcah7Jjns6vkju1DNatEsaEEI2y2M 4n7/rkHeZ3TyFHBUX4e9FomKvGLsAalDBRiqsuxLSOPMU8rGrNLAslOAtKwvp90X 4ht3M2VP098l =btwh -----END PGP SIGNATURE----- Merge tag 'sysctl-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux Pull sysctl updates from Luis Chamberlain: "For two kernel releases now kernel/sysctl.c has been being cleaned up slowly, since the tables were grossly long, sprinkled with tons of #ifdefs and all this caused merge conflicts with one susbystem or another. This tree was put together to help try to avoid conflicts with these cleanups going on different trees at time. So nothing exciting on this pull request, just cleanups. Thanks a lot to the Uniontech and Huawei folks for doing some of this nasty work" * tag 'sysctl-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: (28 commits) sched: Fix build warning without CONFIG_SYSCTL reboot: Fix build warning without CONFIG_SYSCTL kernel/kexec_core: move kexec_core sysctls into its own file sysctl: minor cleanup in new_dir() ftrace: fix building with SYSCTL=y but DYNAMIC_FTRACE=n fs/proc: Introduce list_for_each_table_entry for proc sysctl mm: fix unused variable kernel warning when SYSCTL=n latencytop: move sysctl to its own file ftrace: fix building with SYSCTL=n but DYNAMIC_FTRACE=y ftrace: Fix build warning ftrace: move sysctl_ftrace_enabled to ftrace.c kernel/do_mount_initrd: move real_root_dev sysctls to its own file kernel/delayacct: move delayacct sysctls to its own file kernel/acct: move acct sysctls to its own file kernel/panic: move panic sysctls to its own file kernel/lockdep: move lockdep sysctls to its own file mm: move page-writeback sysctls to their own file mm: move oom_kill sysctls to their own file kernel/reboot: move reboot sysctls to its own file sched: Move energy_aware sysctls to topology.c ... |
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Waiman Long
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434e09e757 |
locking/qrwlock: Change "queue rwlock" to "queued rwlock"
Queued rwlock was originally named "queue rwlock" which wasn't quite grammatically correct. However there are still some "queue rwlock" references in the code. Change those to "queued rwlock" for consistency. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20220510192134.434753-1-longman@redhat.com |
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tangmeng
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f79c9b8ae8 |
kernel/lockdep: move lockdep sysctls to its own file
kernel/sysctl.c is a kitchen sink where everyone leaves their dirty dishes, this makes it very difficult to maintain. To help with this maintenance let's start by moving sysctls to places where they actually belong. The proc sysctl maintainers do not want to know what sysctl knobs you wish to add for your own piece of code, we just care about the core logic. All filesystem syctls now get reviewed by fs folks. This commit follows the commit of fs, move the prove_locking and lock_stat sysctls to its own file, kernel/lockdep.c. Signed-off-by: tangmeng <tangmeng@uniontech.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> |
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Peter Zijlstra
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dc1f7893a7 |
locking/mutex: Make contention tracepoints more consistent wrt adaptive spinning
Have the trace_contention_*() tracepoints consistently include adaptive spinning. In order to differentiate between the spinning and non-spinning states add LCB_F_MUTEX and combine with LCB_F_SPIN. The consequence is that a mutex contention can now triggler multiple _begin() tracepoints before triggering an _end(). Additionally, this fixes one path where mutex would trigger _end() without ever seeing a _begin(). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> |
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Namhyung Kim
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ee042be16c |
locking: Apply contention tracepoints in the slow path
Adding the lock contention tracepoints in various lock function slow paths. Note that each arch can define spinlock differently, I only added it only to the generic qspinlock for now. Signed-off-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Link: https://lkml.kernel.org/r/20220322185709.141236-3-namhyung@kernel.org |
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Namhyung Kim
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16edd9b511 |
locking: Add lock contention tracepoints
This adds two new lock contention tracepoints like below: * lock:contention_begin * lock:contention_end The lock:contention_begin takes a flags argument to classify locks. I found it useful to identify what kind of locks it's tracing like if it's spinning or sleeping, reader-writer lock, real-time, and per-cpu. Move tracepoint definitions into mutex.c so that we can use them without lockdep. Signed-off-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Link: https://lkml.kernel.org/r/20220322185709.141236-2-namhyung@kernel.org |
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Waiman Long
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1ee326196c |
locking/rwsem: Always try to wake waiters in out_nolock path
For writers, the out_nolock path will always attempt to wake up waiters. This may not be really necessary if the waiter to be removed is not the first one. For readers, no attempt to wake up waiter is being made. However, if the HANDOFF bit is set and the reader to be removed is the first waiter, the waiter behind it will inherit the HANDOFF bit and for a write lock waiter waking it up will allow it to spin on the lock to acquire it faster. So it can be beneficial to do a wakeup in this case. Add a new rwsem_del_wake_waiter() helper function to do that consistently for both reader and writer out_nolock paths. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20220322152059.2182333-4-longman@redhat.com |
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Waiman Long
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54c1ee4d61 |
locking/rwsem: Conditionally wake waiters in reader/writer slowpaths
In an analysis of a recent vmcore, a reader-owned rwsem was found with 385 readers but no writer in the wait queue. That is kind of unusual but it may be caused by some race conditions that we have not fully understood yet. In such a case, all the readers in the wait queue should join the other reader-owners and acquire the read lock. In rwsem_down_write_slowpath(), an incoming writer will try to wake up the front readers under such circumstance. That is not the case for rwsem_down_read_slowpath(), add a new helper function rwsem_cond_wake_waiter() to do wakeup and use it in both reader and writer slowpaths to have a consistent and correct behavior. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20220322152059.2182333-3-longman@redhat.com |
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Waiman Long
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f9e21aa9e6 |
locking/rwsem: No need to check for handoff bit if wait queue empty
Since commit
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Nick Desaulniers
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8b023accc8 |
lockdep: Fix -Wunused-parameter for _THIS_IP_
While looking into a bug related to the compiler's handling of addresses of labels, I noticed some uses of _THIS_IP_ seemed unused in lockdep. Drive by cleanup. -Wunused-parameter: kernel/locking/lockdep.c:1383:22: warning: unused parameter 'ip' kernel/locking/lockdep.c:4246:48: warning: unused parameter 'ip' kernel/locking/lockdep.c:4844:19: warning: unused parameter 'ip' Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Waiman Long <longman@redhat.com> Link: https://lore.kernel.org/r/20220314221909.2027027-1-ndesaulniers@google.com |
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Linus Torvalds
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ebd326ce72 |
Changes in this cycle were:
- bitops & cpumask:
- Always inline various generic helpers, to improve code generation,
but also for instrumentation, found by noinstr validation.
- Add a x86-specific cpumask_clear_cpu() helper to improve code generation
- atomics:
- Fix atomic64_{read_acquire,set_release} fallbacks
- lockdep:
- Fix /proc/lockdep output loop iteration for classes
- Fix /proc/lockdep potential access to invalid memory
- minor cleanups
- Add Mark Rutland as reviewer for atomic primitives
- jump labels:
- Clean up the code a bit
- misc:
- Add __sched annotations to percpu rwsem primitives
- Enable RT_MUTEXES on PREEMPT_RT by default
- Stray v8086_mode() inlining fix, result of noinstr objtool validation
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'locking-core-2022-03-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
"Changes in this cycle were:
Bitops & cpumask:
- Always inline various generic helpers, to improve code generation,
but also for instrumentation, found by noinstr validation.
- Add a x86-specific cpumask_clear_cpu() helper to improve code
generation
Atomics:
- Fix atomic64_{read_acquire,set_release} fallbacks
Lockdep:
- Fix /proc/lockdep output loop iteration for classes
- Fix /proc/lockdep potential access to invalid memory
- Add Mark Rutland as reviewer for atomic primitives
- Minor cleanups
Jump labels:
- Clean up the code a bit
Misc:
- Add __sched annotations to percpu rwsem primitives
- Enable RT_MUTEXES on PREEMPT_RT by default
- Stray v8086_mode() inlining fix, result of noinstr objtool
validation"
* tag 'locking-core-2022-03-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
jump_label: Refactor #ifdef of struct static_key
jump_label: Avoid unneeded casts in STATIC_KEY_INIT_{TRUE,FALSE}
locking/lockdep: Iterate lock_classes directly when reading lockdep files
x86/ptrace: Always inline v8086_mode() for instrumentation
cpumask: Add a x86-specific cpumask_clear_cpu() helper
locking: Enable RT_MUTEXES by default on PREEMPT_RT.
locking/local_lock: Make the empty local_lock_*() function a macro.
atomics: Fix atomic64_{read_acquire,set_release} fallbacks
locking: Add missing __sched attributes
cpumask: Always inline helpers which use bit manipulation functions
asm-generic/bitops: Always inline all bit manipulation helpers
locking/lockdep: Avoid potential access of invalid memory in lock_class
lockdep: Use memset_startat() helper in reinit_class()
MAINTAINERS: add myself as reviewer for atomics
|
|
|
Waiman Long
|
fb7275acd6 |
locking/lockdep: Iterate lock_classes directly when reading lockdep files
When dumping lock_classes information via /proc/lockdep, we can't take the lockdep lock as the lock hold time is indeterminate. Iterating over all_lock_classes without holding lock can be dangerous as there is a slight chance that it may branch off to other lists leading to infinite loop or even access invalid memory if changes are made to all_lock_classes list in parallel. To avoid this problem, iteration of lock classes is now done directly on the lock_classes array itself. The lock_classes_in_use bitmap is checked to see if the lock class is being used. To avoid iterating the full array all the times, a new max_lock_class_idx value is added to track the maximum lock_class index that is currently being used. We can theoretically take the lockdep lock for iterating all_lock_classes when other lockdep files (lockdep_stats and lock_stat) are accessed as the lock hold time will be shorter for them. For consistency, they are also modified to iterate the lock_classes array directly. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20220211035526.1329503-2-longman@redhat.com |
|
Cheng Jui Wang
|
28df029d53 |
lockdep: Correct lock_classes index mapping
A kernel exception was hit when trying to dump /proc/lockdep_chains after lockdep report "BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!": Unable to handle kernel paging request at virtual address 00054005450e05c3 ... 00054005450e05c3] address between user and kernel address ranges ... pc : [0xffffffece769b3a8] string+0x50/0x10c lr : [0xffffffece769ac88] vsnprintf+0x468/0x69c ... Call trace: string+0x50/0x10c vsnprintf+0x468/0x69c seq_printf+0x8c/0xd8 print_name+0x64/0xf4 lc_show+0xb8/0x128 seq_read_iter+0x3cc/0x5fc proc_reg_read_iter+0xdc/0x1d4 The cause of the problem is the function lock_chain_get_class() will shift lock_classes index by 1, but the index don't need to be shifted anymore since commit |
|
Minchan Kim
|
c441e934b6 |
locking: Add missing __sched attributes
This patch adds __sched attributes to a few missing places to show blocked function rather than locking function in get_wchan. Signed-off-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20220115231657.84828-1-minchan@kernel.org |
|
|
Waiman Long
|
61cc4534b6 |
locking/lockdep: Avoid potential access of invalid memory in lock_class
It was found that reading /proc/lockdep after a lockdep splat may
potentially cause an access to freed memory if lockdep_unregister_key()
is called after the splat but before access to /proc/lockdep [1]. This
is due to the fact that graph_lock() call in lockdep_unregister_key()
fails after the clearing of debug_locks by the splat process.
After lockdep_unregister_key() is called, the lock_name may be freed
but the corresponding lock_class structure still have a reference to
it. That invalid memory pointer will then be accessed when /proc/lockdep
is read by a user and a use-after-free (UAF) error will be reported if
KASAN is enabled.
To fix this problem, lockdep_unregister_key() is now modified to always
search for a matching key irrespective of the debug_locks state and
zap the corresponding lock class if a matching one is found.
[1] https://lore.kernel.org/lkml/77f05c15-81b6-bddd-9650-80d5f23fe330@i-love.sakura.ne.jp/
Fixes:
|
|
Xiu Jianfeng
|
e204193b13 |
lockdep: Use memset_startat() helper in reinit_class()
use memset_startat() helper to simplify the code, there is no functional change in this patch. Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20211213132618.105737-1-xiujianfeng@huawei.com |
|
|
Minchan Kim
|
4a57d6bbae |
locking/rwlocks: introduce write_lock_nested
In preparation for converting bit_spin_lock to rwlock in zsmalloc so that multiple writers of zspages can run at the same time but those zspages are supposed to be different zspage instance. Thus, it's not deadlock. This patch adds write_lock_nested to support the case for LOCKDEP. [minchan@kernel.org: fix write_lock_nested for RT] Link: https://lkml.kernel.org/r/YZfrMTAXV56HFWJY@google.com [bigeasy@linutronix.de: fixup write_lock_nested() implementation] Link: https://lkml.kernel.org/r/20211123170134.y6xb7pmpgdn4m3bn@linutronix.de Link: https://lkml.kernel.org/r/20211115185909.3949505-8-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Naresh Kamboju <naresh.kamboju@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
|
Linus Torvalds
|
daadb3bd0e |
Peter Zijlstra says:
"Lots of cleanups and preparation; highlights:
- futex: Cleanup and remove runtime futex_cmpxchg detection
- rtmutex: Some fixes for the PREEMPT_RT locking infrastructure
- kcsan: Share owner_on_cpu() between mutex,rtmutex and rwsem and
annotate the racy owner->on_cpu access *once*.
- atomic64: Dead-Code-Elemination"
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Merge tag 'locking_core_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Borislav Petkov:
"Lots of cleanups and preparation. Highlights:
- futex: Cleanup and remove runtime futex_cmpxchg detection
- rtmutex: Some fixes for the PREEMPT_RT locking infrastructure
- kcsan: Share owner_on_cpu() between mutex,rtmutex and rwsem and
annotate the racy owner->on_cpu access *once*.
- atomic64: Dead-Code-Elemination"
[ Description above by Peter Zijlstra ]
* tag 'locking_core_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/atomic: atomic64: Remove unusable atomic ops
futex: Fix additional regressions
locking: Allow to include asm/spinlock_types.h from linux/spinlock_types_raw.h
x86/mm: Include spinlock_t definition in pgtable.
locking: Mark racy reads of owner->on_cpu
locking: Make owner_on_cpu() into <linux/sched.h>
lockdep/selftests: Adapt ww-tests for PREEMPT_RT
lockdep/selftests: Skip the softirq related tests on PREEMPT_RT
lockdep/selftests: Unbalanced migrate_disable() & rcu_read_lock().
lockdep/selftests: Avoid using local_lock_{acquire|release}().
lockdep: Remove softirq accounting on PREEMPT_RT.
locking/rtmutex: Add rt_mutex_lock_nest_lock() and rt_mutex_lock_killable().
locking/rtmutex: Squash self-deadlock check for ww_rt_mutex.
locking: Remove rt_rwlock_is_contended().
sched: Trigger warning if ->migration_disabled counter underflows.
futex: Fix sparc32/m68k/nds32 build regression
futex: Remove futex_cmpxchg detection
futex: Ensure futex_atomic_cmpxchg_inatomic() is present
kernel/locking: Use a pointer in ww_mutex_trylock().
|
|
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Linus Torvalds
|
e7d38f16c2 |
RCU pull request for v5.17
This pull request contains the following branches: doc.2021.11.30c: Documentation updates, perhaps most notably Neil Brown's writeup of the reference-counting analogy to RCU. exp.2021.12.07a: Expedited grace-period cleanups. fastnohz.2021.11.30c: Remove CONFIG_RCU_FAST_NO_HZ due to lack of valid users. I have asked around, posted a blog entry, and sent this series to LKML without result. fixes.2021.11.30c: Miscellaneous fixes. nocb.2021.12.09a: RCU callback offloading updates, perhaps most notably Frederic Weisbecker's updates allowing CPUs booted in the de-offloaded state to be offloaded at runtime. nolibc.2021.11.30c: nolibc fixes from Willy Tarreau and Anmar Faizi, but also including Mark Brown's addition of gettid(). tasks.2021.12.09a: RCU Tasks Trace fixes, including changes that increase the scalability of call_rcu_tasks_trace() for the BPF folks (Martin Lau and KP Singh). torture.2021.12.07a: Various fixes including those from Wander Lairson Costa and Li Zhijian. torturescript.2021.11.30c: Fixes plus addition of tests for the increased call_rcu_tasks_trace() scalability. -----BEGIN PGP SIGNATURE----- iQJHBAABCgAxFiEEbK7UrM+RBIrCoViJnr8S83LZ+4wFAmHbtukTHHBhdWxtY2tA a2VybmVsLm9yZwAKCRCevxLzctn7jAX3D/4mrDqAPhAWLWKp7klRhvwypDxj0cxd /TuGNcZN+YdvNfwozcrog+8yiPxcxhNW1pMESi7SolAhRwuk1JEjiclY+7ORYd6a /dmJB/lQBezGAdgVabRaJjfLKikpQ+/EnzKee3jjTS1XhJRJe/hDwlVP2B6IROfy iko5yi+hxfhQdPW6UcpTPCl/4Jn63d9+2SIlW16H0LhzlJeYYsWz4tqOEKYeiHeB Zxq90InCVmb3YYJzOtk/G7pGQ2RxKPR6/ilm87yzAfJD0Dawd2pgYeDoGvzx94S6 CmhvA6GmwO3JOL6lH891AQVXskCODSJdosP/7otm9u36XJT+5lNOeLRsLbS0Sd9t BrJKfC7wBFuuIug8j5k3+QSXiKB7Q5JpXEhOjH4BIrkSL0Z0jSVsrZwCSbiUkjZZ CdF19bL+4h4x5ZL3pndsplX+9BDXsKEgGHWeuzzB4rmsUMtBg84HyfbPp8mLxm6B i7a1hNVQ5rFWYj6TpI1ZgOBIX07i21OyMAUbXn5JSWUmOyPp2V6D4Sp1zdlvRM0r hKkIg73NP6ah9QZQTp7T1rIjVmFc2KjbmNZQegjR2pHykPCChT6xnlFix4InV4Ma BDtigP6vhWz1YfKPjek5WESzHmMRoxdpFjqDY//Uj8/bKBccldO0osERKWtdDlDL bwMNjny3PPLRng== =K6AN -----END PGP SIGNATURE----- Merge tag 'rcu.2022.01.09a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu Pull RCU updates from Paul McKenney: - Documentation updates, perhaps most notably Neil Brown's writeup of the reference-counting analogy to RCU. - Expedited grace-period cleanups. - Remove CONFIG_RCU_FAST_NO_HZ due to lack of valid users. I have asked around, posted a blog entry, and sent this series to LKML without result. - Miscellaneous fixes. - RCU callback offloading updates, perhaps most notably Frederic Weisbecker's updates allowing CPUs booted in the de-offloaded state to be offloaded at runtime. - nolibc fixes from Willy Tarreau and Anmar Faizi, but also including Mark Brown's addition of gettid(). - RCU Tasks Trace fixes, including changes that increase the scalability of call_rcu_tasks_trace() for the BPF folks (Martin Lau and KP Singh). - Various fixes including those from Wander Lairson Costa and Li Zhijian. - Fixes plus addition of tests for the increased call_rcu_tasks_trace() scalability. * tag 'rcu.2022.01.09a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (87 commits) rcu/nocb: Merge rcu_spawn_cpu_nocb_kthread() and rcu_spawn_one_nocb_kthread() rcu/nocb: Allow empty "rcu_nocbs" kernel parameter rcu/nocb: Create kthreads on all CPUs if "rcu_nocbs=" or "nohz_full=" are passed rcu/nocb: Optimize kthreads and rdp initialization rcu/nocb: Prepare nocb_cb_wait() to start with a non-offloaded rdp rcu/nocb: Remove rcu_node structure from nocb list when de-offloaded rcu-tasks: Use fewer callbacks queues if callback flood ends rcu-tasks: Use separate ->percpu_dequeue_lim for callback dequeueing rcu-tasks: Use more callback queues if contention encountered rcu-tasks: Avoid raw-spinlocked wakeups from call_rcu_tasks_generic() rcu-tasks: Count trylocks to estimate call_rcu_tasks() contention rcu-tasks: Add rcupdate.rcu_task_enqueue_lim to set initial queueing rcu-tasks: Make rcu_barrier_tasks*() handle multiple callback queues rcu-tasks: Use workqueues for multiple rcu_tasks_invoke_cbs() invocations rcu-tasks: Abstract invocations of callbacks rcu-tasks: Abstract checking of callback lists rcu-tasks: Add a ->percpu_enqueue_lim to the rcu_tasks structure rcu-tasks: Inspect stalled task's trc state in locked state rcu-tasks: Use spin_lock_rcu_node() and friends rcutorture: Combine n_max_cbs from all kthreads in a callback flood ... |
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Thomas Gleixner
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f16cc980d6 |
Merge branch 'locking/urgent' into locking/core
Pick up the spin loop condition fix. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
|
Zqiang
|
8f556a326c |
locking/rtmutex: Fix incorrect condition in rtmutex_spin_on_owner()
Optimistic spinning needs to be terminated when the spinning waiter is not
longer the top waiter on the lock, but the condition is negated. It
terminates if the waiter is the top waiter, which is defeating the whole
purpose.
Fixes:
|
|
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Ingo Molnar
|
6773cc31a9 |
Linux 5.16-rc5
-----BEGIN PGP SIGNATURE----- iQFSBAABCAA8FiEEq68RxlopcLEwq+PEeb4+QwBBGIYFAmG2fU0eHHRvcnZhbGRz QGxpbnV4LWZvdW5kYXRpb24ub3JnAAoJEHm+PkMAQRiGC7EH/3R7Rt+OD8Wn8Ss3 w8V+dBxVwa2u2oMTyUHPxaeOXZ7bi38XlUdLFPOK/76bGwO0a5TmYZqsWdRbGyT0 HfcYjHsQ0lbJXk/nh2oM47oJxJXVpThIHXJEk0FZ0Y5t+DYjIYlNHzqZymUyhLem St74zgWcyT+MXuqY34vB827FJDUnOxhhhi85tObeunaSPAomy9aiYidSC1ARREnz iz2VUntP/QnRnKVvL2nUZNzcz1xL5vfCRSKsRGRSv3qW1Y/1M71ylt6JVmSftWq+ VmMdFxFhdrb1OK/1ct/930Un/UP2NG9EJsWxote2XYlnVSZHzDqH7lUhbqgdCcLz 1m2tVNY= =7wRd -----END PGP SIGNATURE----- Merge tag 'v5.16-rc5' into locking/core, to pick up fixes Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Li Zhijian
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81faa4f6fb |
locktorture,rcutorture,torture: Always log error message
Unconditionally log messages corresponding to errors. Acked-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Li Zhijian <zhijianx.li@intel.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> |
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Kefeng Wang
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c0bed69daf |
locking: Make owner_on_cpu() into <linux/sched.h>
Move the owner_on_cpu() from kernel/locking/rwsem.c into include/linux/sched.h with under CONFIG_SMP, then use it in the mutex/rwsem/rtmutex to simplify the code. Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20211203075935.136808-2-wangkefeng.wang@huawei.com |
|
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Thomas Gleixner
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0c1d7a2c2d |
lockdep: Remove softirq accounting on PREEMPT_RT.
There is not really a softirq context on PREEMPT_RT. Softirqs on
PREEMPT_RT are always invoked within the context of a threaded
interrupt handler or within ksoftirqd. The "in-softirq" context is
preemptible and is protected by a per-CPU lock to ensure mutual
exclusion.
There is no difference on PREEMPT_RT between spin_lock_irq() and
spin_lock() because the former does not disable interrupts. Therefore
if a lock is used in_softirq() and locked once with spin_lock_irq()
then lockdep will report this with "inconsistent {SOFTIRQ-ON-W} ->
{IN-SOFTIRQ-W} usage".
Teach lockdep that we don't really do softirqs on -RT.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20211129174654.668506-6-bigeasy@linutronix.de
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Sebastian Andrzej Siewior
|
a364202192 |
locking/rtmutex: Add rt_mutex_lock_nest_lock() and rt_mutex_lock_killable().
The locking selftest for ww-mutex expects to operate directly on the base-mutex which becomes a rtmutex on PREEMPT_RT. Add a rtmutex based implementation of mutex_lock_nest_lock() and mutex_lock_killable() named rt_mutex_lock_nest_lock() abd rt_mutex_lock_killable(). Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20211129174654.668506-5-bigeasy@linutronix.de |
|
|
Peter Zijlstra
|
02ea9fc96f |
locking/rtmutex: Squash self-deadlock check for ww_rt_mutex.
Similar to the issues in commits: |
|
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Sebastian Andrzej Siewior
|
e08f343be0 |
locking: Remove rt_rwlock_is_contended().
rt_rwlock_is_contended() has no users. It makes no sense to use it as rwlock_is_contended() because it is a sleeping lock on RT and preemption is possible. It reports always != 0 if used by a writer and even if there is a waiter then the lock might not be handed over if the current owner has the highest priority. Remove rt_rwlock_is_contended(). Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20211129174654.668506-3-bigeasy@linutronix.de |
|
Muchun Song
|
14c2404884 |
locking/rwsem: Optimize down_read_trylock() under highly contended case
We found that a process with 10 thousnads threads has been encountered
a regression problem from Linux-v4.14 to Linux-v5.4. It is a kind of
workload which will concurrently allocate lots of memory in different
threads sometimes. In this case, we will see the down_read_trylock()
with a high hotspot. Therefore, we suppose that rwsem has a regression
at least since Linux-v5.4. In order to easily debug this problem, we
write a simply benchmark to create the similar situation lile the
following.
```c++
#include <sys/mman.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sched.h>
#include <cstdio>
#include <cassert>
#include <thread>
#include <vector>
#include <chrono>
volatile int mutex;
void trigger(int cpu, char* ptr, std::size_t sz)
{
cpu_set_t set;
CPU_ZERO(&set);
CPU_SET(cpu, &set);
assert(pthread_setaffinity_np(pthread_self(), sizeof(set), &set) == 0);
while (mutex);
for (std::size_t i = 0; i < sz; i += 4096) {
*ptr = '\0';
ptr += 4096;
}
}
int main(int argc, char* argv[])
{
std::size_t sz = 100;
if (argc > 1)
sz = atoi(argv[1]);
auto nproc = std:🧵:hardware_concurrency();
std::vector<std::thread> thr;
sz <<= 30;
auto* ptr = mmap(nullptr, sz, PROT_READ | PROT_WRITE, MAP_ANON |
MAP_PRIVATE, -1, 0);
assert(ptr != MAP_FAILED);
char* cptr = static_cast<char*>(ptr);
auto run = sz / nproc;
run = (run >> 12) << 12;
mutex = 1;
for (auto i = 0U; i < nproc; ++i) {
thr.emplace_back(std::thread([i, cptr, run]() { trigger(i, cptr, run); }));
cptr += run;
}
rusage usage_start;
getrusage(RUSAGE_SELF, &usage_start);
auto start = std::chrono::system_clock::now();
mutex = 0;
for (auto& t : thr)
t.join();
rusage usage_end;
getrusage(RUSAGE_SELF, &usage_end);
auto end = std::chrono::system_clock::now();
timeval utime;
timeval stime;
timersub(&usage_end.ru_utime, &usage_start.ru_utime, &utime);
timersub(&usage_end.ru_stime, &usage_start.ru_stime, &stime);
printf("usr: %ld.%06ld\n", utime.tv_sec, utime.tv_usec);
printf("sys: %ld.%06ld\n", stime.tv_sec, stime.tv_usec);
printf("real: %lu\n",
std::chrono::duration_cast<std::chrono::milliseconds>(end -
start).count());
return 0;
}
```
The functionality of above program is simply which creates `nproc`
threads and each of them are trying to touch memory (trigger page
fault) on different CPU. Then we will see the similar profile by
`perf top`.
25.55% [kernel] [k] down_read_trylock
14.78% [kernel] [k] handle_mm_fault
13.45% [kernel] [k] up_read
8.61% [kernel] [k] clear_page_erms
3.89% [kernel] [k] __do_page_fault
The highest hot instruction, which accounts for about 92%, in
down_read_trylock() is cmpxchg like the following.
91.89 │ lock cmpxchg %rdx,(%rdi)
Sice the problem is found by migrating from Linux-v4.14 to Linux-v5.4,
so we easily found that the commit
|
|
|
Waiman Long
|
d257cc8cb8 |
locking/rwsem: Make handoff bit handling more consistent
There are some inconsistency in the way that the handoff bit is being
handled in readers and writers that lead to a race condition.
Firstly, when a queue head writer set the handoff bit, it will clear
it when the writer is being killed or interrupted on its way out
without acquiring the lock. That is not the case for a queue head
reader. The handoff bit will simply be inherited by the next waiter.
Secondly, in the out_nolock path of rwsem_down_read_slowpath(), both
the waiter and handoff bits are cleared if the wait queue becomes
empty. For rwsem_down_write_slowpath(), however, the handoff bit is
not checked and cleared if the wait queue is empty. This can
potentially make the handoff bit set with empty wait queue.
Worse, the situation in rwsem_down_write_slowpath() relies on wstate,
a variable set outside of the critical section containing the ->count
manipulation, this leads to race condition where RWSEM_FLAG_HANDOFF
can be double subtracted, corrupting ->count.
To make the handoff bit handling more consistent and robust, extract
out handoff bit clearing code into the new rwsem_del_waiter() helper
function. Also, completely eradicate wstate; always evaluate
everything inside the same critical section.
The common function will only use atomic_long_andnot() to clear bits
when the wait queue is empty to avoid possible race condition. If the
first waiter with handoff bit set is killed or interrupted to exit the
slowpath without acquiring the lock, the next waiter will inherit the
handoff bit.
While at it, simplify the trylock for loop in
rwsem_down_write_slowpath() to make it easier to read.
Fixes:
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Sebastian Andrzej Siewior
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2202e15b2b |
kernel/locking: Use a pointer in ww_mutex_trylock().
mutex_acquire_nest() expects a pointer, pass the pointer.
Fixes:
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Linus Torvalds
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59a2ceeef6 |
Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton: "87 patches. Subsystems affected by this patch series: mm (pagecache and hugetlb), procfs, misc, MAINTAINERS, lib, checkpatch, binfmt, kallsyms, ramfs, init, codafs, nilfs2, hfs, crash_dump, signals, seq_file, fork, sysvfs, kcov, gdb, resource, selftests, and ipc" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (87 commits) ipc/ipc_sysctl.c: remove fallback for !CONFIG_PROC_SYSCTL ipc: check checkpoint_restore_ns_capable() to modify C/R proc files selftests/kselftest/runner/run_one(): allow running non-executable files virtio-mem: disallow mapping virtio-mem memory via /dev/mem kernel/resource: disallow access to exclusive system RAM regions kernel/resource: clean up and optimize iomem_is_exclusive() scripts/gdb: handle split debug for vmlinux kcov: replace local_irq_save() with a local_lock_t kcov: avoid enable+disable interrupts if !in_task() kcov: allocate per-CPU memory on the relevant node Documentation/kcov: define `ip' in the example Documentation/kcov: include types.h in the example sysv: use BUILD_BUG_ON instead of runtime check kernel/fork.c: unshare(): use swap() to make code cleaner seq_file: fix passing wrong private data seq_file: move seq_escape() to a header signal: remove duplicate include in signal.h crash_dump: remove duplicate include in crash_dump.h crash_dump: fix boolreturn.cocci warning hfs/hfsplus: use WARN_ON for sanity check ... |
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Kefeng Wang
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1b1ad288b8 |
kallsyms: remove arch specific text and data check
Patch series "sections: Unify kernel sections range check and use", v4.
There are three head files(kallsyms.h, kernel.h and sections.h) which
include the kernel sections range check, let's make some cleanup and unify
them.
1. cleanup arch specific text/data check and fix address boundary check
in kallsyms.h
2. make all the basic/core kernel range check function into sections.h
3. update all the callers, and use the helper in sections.h to simplify
the code
After this series, we have 5 APIs about kernel sections range check in
sections.h
* is_kernel_rodata() --- already in sections.h
* is_kernel_core_data() --- come from core_kernel_data() in kernel.h
* is_kernel_inittext() --- come from kernel.h and kallsyms.h
* __is_kernel_text() --- add new internal helper
* __is_kernel() --- add new internal helper
Note: For the last two helpers, people should not use directly, consider to
use corresponding function in kallsyms.h.
This patch (of 11):
Remove arch specific text and data check after commit
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