Paul E. McKenney e4453d8a1c rcu: Make rcu_read_unlock_special() safe for rq/pi locks ... The scheduler is currently required to hold rq/pi locks across the entire RCU read-side critical section or not at all. This is inconvenient and leaves traps for the unwary, including the author of this commit. But now that excessively long grace periods enable scheduling-clock interrupts for holdout nohz_full CPUs, the nohz_full rescue logic in rcu_read_unlock_special() can be dispensed with. In other words, the rcu_read_unlock_special() function can refrain from doing wakeups unless such wakeups are guaranteed safe. This commit therefore avoids unsafe wakeups, freeing the scheduler to hold rq/pi locks across rcu_read_unlock() even if the corresponding RCU read-side critical section might have been preempted. This commit also updates RCU's requirements documentation. This commit is inspired by a patch from Lai Jiangshan: https://lore.kernel.org/lkml/20191102124559.1135-2-laijs@linux.alibaba.com This commit is further intended to be a step towards his goal of permitting the inlining of RCU-preempt's rcu_read_lock() and rcu_read_unlock(). Cc: Lai Jiangshan <laijs@linux.alibaba.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>		2020-04-27 11:03:50 -07:00
..
ABI	change email address for Pali Rohár	2020-04-10 15:36:22 -07:00
PCI	pci-v5.7-changes	2020-04-03 14:25:02 -07:00
RCU	rcu: Make rcu_read_unlock_special() safe for rq/pi locks	2020-04-27 11:03:50 -07:00
accounting	doc: cgroup: improve formatting of references	2020-03-02 12:57:03 -07:00
admin-guide	docs: admin-guide: merge sections for the kernel.modprobe sysctl	2020-04-15 14:50:09 -06:00
arm	docs: arm: tcm: Fix a few typos	2020-02-19 02:42:21 -07:00
arm64	arm64 updates for 5.7:	2020-03-31 10:05:01 -07:00
block	block: Document genhd capability flags	2020-03-12 07:47:22 -06:00
bpf	bpf: lsm: Add Documentation	2020-03-30 01:35:12 +02:00
cdrom	docs: add some directories to the main documentation index	2019-07-15 11:03:03 -03:00
core-api	docs: timekeeping: Use correct prototype for deprecated functions	2020-04-15 14:48:26 -06:00
cpu-freq	docs: cpu-freq: convert cpufreq-stats.txt to ReST	2020-03-06 00:01:02 +01:00
crypto	crypto: algapi - make unregistration functions return void	2019-12-20 14:58:35 +08:00
dev-tools	linux-kselftest-kunit-5.7-rc1	2020-04-01 16:11:40 -07:00
devicetree	Devicetree fixes for v5.7:	2020-04-17 11:35:20 -07:00
doc-guide	Documentation: build warnings related to missing blank lines after explicit markups has been fixed	2020-02-05 10:30:03 -07:00
driver-api	A handful of late-arriving fixes for the documentation tree.	2020-04-10 17:53:43 -07:00
fault-injection	docs: add some directories to the main documentation index	2019-07-15 11:03:03 -03:00
fb	fbdev: fbmem: allow overriding the number of bootup logos	2020-01-03 14:27:40 +01:00
features	documentation: vm: Advertise support for pte_special in riscv	2020-02-19 02:41:01 -07:00
filesystems	A handful of late-arriving fixes for the documentation tree.	2020-04-10 17:53:43 -07:00
firmware-guide	Documentation: firmware-guide: ACPI: fix table alignment in namespace.rst	2020-04-08 14:27:48 +02:00
firmware_class	…
fpga	Documentation: fpga: dfl: add descriptions for thermal/power management interfaces	2019-10-16 19:18:26 -07:00
gpu	UAPI Changes:	2020-03-19 10:40:27 +10:00
hid	docs: add some documentation dirs to the driver-api book	2019-07-15 11:03:02 -03:00
hwmon	hwmon: (pmbus/isl68137) Fix up chip IDs	2020-04-12 15:12:51 -07:00
i2c	i2c: convert SMBus alert setup function to return an ERRPTR	2020-03-10 12:19:52 +01:00
ia64	docs: add SPDX tags to new index files	2019-07-15 11:03:03 -03:00
ide	docs: add some directories to the main documentation index	2019-07-15 11:03:03 -03:00
iio	docs: add some documentation dirs to the driver-api book	2019-07-15 11:03:02 -03:00
infiniband	Documentation/infiniband: update name of some functions	2019-09-13 16:55:55 -03:00
input	Input: docs: fix spelling mistake "potocol" -> "protocol"	2019-08-06 11:24:49 -06:00
isdn	isdn: capi: dead code removal	2019-12-11 09:12:38 +01:00
kbuild	kbuild: support LLVM=1 to switch the default tools to Clang/LLVM	2020-04-09 03:18:21 +09:00
kernel-hacking	docs: locking: Drop :c:func: throughout	2020-03-20 17:16:24 -06:00
leds	leds: core: Add support for composing LED class device names	2019-07-25 20:07:52 +02:00
livepatch	livepatch: Documentation of the new API for tracking system state changes	2019-11-01 13:08:24 +01:00
locking	Documentation/locking/locktypes: Minor copy editor fixes	2020-03-28 12:47:34 +01:00
m68k	docs: README.buddha: convert to ReST and add to m68k book	2019-07-31 13:30:10 -06:00
maintainer	Add a maintainer entry profile for documentation	2020-01-24 09:48:39 -07:00
media	media updates for v5.7-rc1	2020-03-30 13:42:05 -07:00
mhi	docs: Add documentation for MHI bus	2020-03-19 07:41:04 +01:00
mips	docs: mips: remove no longer needed au1xxx_ide.rst documentation	2020-03-24 15:53:48 +01:00
misc-devices	Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6	2020-04-01 14:47:40 -07:00
netlabel	docs: add some directories to the main documentation index	2019-07-15 11:03:03 -03:00
networking	Documentation: Fix tcp_challenge_ack_limit default value	2020-04-15 16:22:59 -07:00
nios2	docs: nios2: add it to the main Documentation body	2019-07-31 13:31:51 -06:00
nvdimm	docs: nvdimm: use ReST notation for subsection	2020-01-24 09:54:42 -07:00
openrisc	openrisc: configs: Cleanup CONFIG_CROSS_COMPILE	2020-01-31 22:10:58 +09:00
parisc	docs: parisc: convert to ReST and add to documentation body	2019-07-31 13:30:15 -06:00
pcmcia	docs: add some directories to the main documentation index	2019-07-15 11:03:03 -03:00
power	Merge branches 'pm-core', 'pm-sleep', 'pm-acpi' and 'pm-domains'	2020-03-30 14:46:58 +02:00
powerpc	powerpc updates for 5.7	2020-04-05 11:12:59 -07:00
process	Documentation/changes: Raise minimum supported binutils version to 2.23	2020-04-09 00:02:00 +09:00
riscv	It has been a relatively quiet cycle for documentation, but there's still a	2020-01-29 15:27:31 -08:00
s390	Documentation/s390: remove outdated debugging390 documentation	2019-08-21 12:41:43 +02:00
scheduler	Documentation/scheduler: fix links in sched-stats	2019-10-29 04:35:41 -06:00
scsi	SCSI misc on 20200402	2020-04-02 17:03:53 -07:00
security	docs: prevent warnings due to autosectionlabel	2020-03-20 17:01:29 -06:00
sh	docs: remove extra conf.py files	2019-07-17 06:57:52 -03:00
sound	ALSA: hda/realtek - Remove now-unnecessary XPS 13 headphone noise fixups	2020-03-31 10:54:06 +02:00
sparc	docs: add arch doc directories to the index	2019-07-15 11:03:01 -03:00
sphinx	docs: Fix empty parallelism argument	2020-02-25 03:11:04 -07:00
sphinx-static	doc-rst: Reduce CSS padding around Field	2019-10-02 10:03:06 -06:00
spi	spi: docs: convert to ReST and add it to the kABI bookset	2019-07-31 14:13:13 -06:00
target	docs: prevent warnings due to autosectionlabel	2020-03-20 17:01:29 -06:00
timers	docs: add some directories to the main documentation index	2019-07-15 11:03:03 -03:00
trace	New tracing features:	2020-04-05 10:36:18 -07:00
translations	media updates for v5.7-rc1	2020-03-30 13:42:05 -07:00
usb	usb: gadget: add raw-gadget interface	2020-03-15 11:34:48 +02:00
userspace-api	docs: userspace: ioctl-number: remove mc146818rtc conflict	2020-02-13 11:42:02 -07:00
virt	ARM:	2020-04-02 15:13:15 -07:00
vm	mm/zswap: allow setting default status, compressor and allocator in Kconfig	2020-04-07 10:43:41 -07:00
w1	docs: w1: Fix a typo in omap-hdq.rst	2019-12-30 11:58:02 -07:00
watchdog	linux-watchdog 5.4-rc1 tag	2019-09-27 11:17:38 -07:00
x86	Documentation/x86, efi/x86: Clarify EFI handover protocol and its requirements	2020-04-14 08:32:15 +02:00
xtensa	docs: add arch doc directories to the index	2019-07-15 11:03:01 -03:00
.gitignore	.gitignore: add SPDX License Identifier	2020-03-25 11:50:48 +01:00
COPYING-logo	docs: logo.txt: rename it to COPYING-logo	2019-07-15 09:20:27 -03:00
Changes	…
CodingStyle	…
DMA-API-HOWTO.txt	docs: DMA-API-HOWTO.txt: fix an unmarked code block	2019-07-15 09:20:24 -03:00
DMA-API.txt	dma-mapping: remove dma_release_declared_memory	2019-09-04 11:13:19 +02:00
DMA-ISA-LPC.txt	…
DMA-attributes.txt	dma-mapping: remove the DMA_ATTR_WRITE_BARRIER flag	2019-11-14 12:01:54 -04:00
IPMI.txt	…
IRQ-affinity.txt	…
IRQ-domain.txt	…
IRQ.txt	…
Kconfig	…
Makefile	Kbuild updates for v5.7	2020-03-31 16:03:39 -07:00
SubmittingPatches	…
asm-annotations.rst	Documentation: Call out example SYM_FUNC_* usage as x86-specific	2020-01-16 12:53:16 -07:00
atomic_bitops.txt	…
atomic_t.txt	Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2019-07-08 16:12:03 -07:00
bus-virt-phys-mapping.txt	…
conf.py	docs: conf.py: avoid thousands of duplicate label warning on Sphinx	2020-03-20 17:01:34 -06:00
crc32.txt	…
debugging-via-ohci1394.txt	…
digsig.txt	…
docutils.conf	…
dontdiff	modpost: dump missing namespaces into a single modules.nsdeps file	2019-11-11 20:10:01 +09:00
futex-requeue-pi.txt	…
hwspinlock.txt	…
index.rst	Char/Misc driver patches for 5.7-rc1	2020-04-03 13:22:40 -07:00
irqflags-tracing.txt	…
kprobes.txt	…
kref.txt	docs: kref: Clarify the use of two kref_put() in example code	2020-02-25 03:39:10 -07:00
logo.gif	…
lzo.txt	…
mailbox.txt	…
memory-barriers.txt	Documentation/memory-barriers: Fix typos	2020-02-27 07:03:14 -08:00
nommu-mmap.txt	…
percpu-rw-semaphore.txt	…
pi-futex.txt	docs: locking: convert docs to ReST and rename to *.rst	2019-07-15 08:53:27 -03:00
preempt-locking.txt	…
rbtree.txt	docs: rbtree.txt: fix Sphinx build warnings	2019-07-15 09:20:24 -03:00
remoteproc.txt	remoteproc: Add elf64 support in elf loader	2020-03-25 22:29:40 -07:00
robust-futex-ABI.txt	threads: Update PID limit comment according to futex UAPI change	2020-03-21 17:48:13 +01:00
robust-futexes.txt	…
rpmsg.txt	…
speculation.txt	…
static-keys.txt	…
tee.txt	Documentation: tee: add AMD-TEE driver details	2020-01-04 13:49:51 +08:00
this_cpu_ops.txt	…
unaligned-memory-access.txt	…
xz.txt	…