Linus Torvalds 596ff4a09b cpumask: re-introduce constant-sized cpumask optimizations ... Commit aa47a7c215 ("lib/cpumask: deprecate nr_cpumask_bits") resulted in the cpumask operations potentially becoming hugely less efficient, because suddenly the cpumask was always considered to be variable-sized. The optimization was then later added back in a limited form by commit 6f9c07be9d ("lib/cpumask: add FORCE_NR_CPUS config option"), but that FORCE_NR_CPUS option is not useful in a generic kernel and more of a special case for embedded situations with fixed hardware. Instead, just re-introduce the optimization, with some changes. Instead of depending on CPUMASK_OFFSTACK being false, and then always using the full constant cpumask width, this introduces three different cpumask "sizes": - the exact size (nr_cpumask_bits) remains identical to nr_cpu_ids. This is used for situations where we should use the exact size. - the "small" size (small_cpumask_bits) is the NR_CPUS constant if it fits in a single word and the bitmap operations thus end up able to trigger the "small_const_nbits()" optimizations. This is used for the operations that have optimized single-word cases that get inlined, notably the bit find and scanning functions. - the "large" size (large_cpumask_bits) is the NR_CPUS constant if it is an sufficiently small constant that makes simple "copy" and "clear" operations more efficient. This is arbitrarily set at four words or less. As a an example of this situation, without this fixed size optimization, cpumask_clear() will generate code like movl nr_cpu_ids(%rip), %edx addq $63, %rdx shrq $3, %rdx andl $-8, %edx callq memset@PLT on x86-64, because it would calculate the "exact" number of longwords that need to be cleared. In contrast, with this patch, using a MAX_CPU of 64 (which is quite a reasonable value to use), the above becomes a single movq $0,cpumask instruction instead, because instead of caring to figure out exactly how many CPU's the system has, it just knows that the cpumask will be a single word and can just clear it all. Note that this does end up tightening the rules a bit from the original version in another way: operations that set bits in the cpumask are now limited to the actual nr_cpu_ids limit, whereas we used to do the nr_cpumask_bits thing almost everywhere in the cpumask code. But if you just clear bits, or scan for bits, we can use the simpler compile-time constants. In the process, remove 'cpumask_complement()' and 'for_each_cpu_not()' which were not useful, and which fundamentally have to be limited to 'nr_cpu_ids'. Better remove them now than have somebody introduce use of them later. Of course, on x86-64 with MAXSMP there is no sane small compile-time constant for the cpumask sizes, and we end up using the actual CPU bits, and will generate the above kind of horrors regardless. Please don't use MAXSMP unless you really expect to have machines with thousands of cores. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2023-03-05 14:30:34 -08:00
..
842
crypto	crypto: lib/blake2s - Split up test function to halve stack usage	2022-12-30 22:56:27 +08:00
dim
fonts	lib/fonts: fix undefined behavior in bit shift for get_default_font	2022-11-18 13:55:09 -08:00
kunit	kunit: Fix 'hooks.o' build by recursing into kunit	2023-02-27 14:49:03 -08:00
livepatch
lz4
lzo
math	math64: favor kernel-doc from header files	2022-11-21 14:30:53 -07:00
mpi	lib/mpi: Fix buffer overrun when SG is too long	2023-01-06 17:15:46 +08:00
pldmfw
raid6	for-6.2/block-2022-12-08	2022-12-13 10:43:59 -08:00
reed_solomon	treewide: use get_random_u32_below() instead of deprecated function	2022-11-18 02:15:15 +01:00
test_fortify
vdso	lib/vdso: use "grep -E" instead of "egrep"	2022-11-23 19:50:15 +01:00
xz
zlib_deflate	lib/zlib: DFLTCC deflate does not write all available bits for Z_NO_FLUSH	2023-02-27 17:00:14 -08:00
zlib_dfltcc	lib/zlib: remove redundation assignement of avail_in dfltcc_gdht()	2023-02-02 22:50:10 -08:00
zlib_inflate	lib/zlib: Split deflate and inflate states for DFLTCC	2023-02-02 22:50:09 -08:00
zstd	zstd: import usptream v1.5.2	2022-10-24 12:12:32 -07:00
.gitignore
argv_split.c
ashldi3.c
ashrdi3.c
asn1_decoder.c
asn1_encoder.c
assoc_array.c
atomic64.c
atomic64_test.c
audit.c
base64.c
bcd.c
bch.c
bitfield_kunit.c
bitmap.c	lib/bitmap: remove bitmap_ord_to_pos	2022-09-26 12:19:12 -07:00
bitrev.c
bootconfig-data.S
bootconfig.c
bsearch.c
btree.c
bucket_locks.c
bug.c	cpuidle: lib/bug: Disable rcu_is_watching() during WARN/BUG	2023-01-31 15:01:45 +01:00
build_OID_registry
buildid.c
bust_spinlocks.c
check_signature.c
checksum.c
clz_ctz.c
clz_tab.c
cmdline.c
cmdline_kunit.c	treewide: use get_random_{u8,u16}() when possible, part 1	2022-10-11 17:42:58 -06:00
cmpdi2.c
compat_audit.c
cpu_rmap.c
cpumask.c	lib/cpumask: update comment for cpumask_local_spread()	2023-02-07 18:20:00 -08:00
cpumask_kunit.c	cpumask: re-introduce constant-sized cpumask optimizations	2023-03-05 14:30:34 -08:00
crc-ccitt.c
crc-itu-t.c
crc-t10dif.c
crc4.c
crc7.c
crc8.c
crc16.c
crc32.c
crc32defs.h
crc32test.c
crc64-rocksoft.c
crc64.c
ctype.c
debug_info.c
debug_locks.c
debugobjects.c	Non-MM patches for 6.2-rc1.	2022-12-12 17:28:58 -08:00
dec_and_lock.c	perf: Fix perf_event_pmu_context serialization	2023-01-31 20:37:18 +01:00
decompress.c
decompress_bunzip2.c
decompress_inflate.c
decompress_unlz4.c
decompress_unlzma.c
decompress_unlzo.c
decompress_unxz.c
decompress_unzstd.c
devmem_is_allowed.c
devres.c
dhry.h	lib: add Dhrystone benchmark test	2023-02-02 22:50:01 -08:00
dhry_1.c	lib: add Dhrystone benchmark test	2023-02-02 22:50:01 -08:00
dhry_2.c	lib: add Dhrystone benchmark test	2023-02-02 22:50:01 -08:00
dhry_run.c	lib: add Dhrystone benchmark test	2023-02-02 22:50:01 -08:00
digsig.c
dump_stack.c
dynamic_debug.c
dynamic_queue_limits.c
earlycpio.c
errname.c	printf: fix errname.c list	2023-02-15 15:44:43 +01:00
error-inject.c	error-injection: remove EI_ETYPE_NONE	2023-02-02 22:50:00 -08:00
errseq.c
extable.c
fault-inject-usercopy.c
fault-inject.c	fault-injection: make stacktrace filter works as expected	2022-12-15 16:40:44 -08:00
fdt.c
fdt_addresses.c
fdt_empty_tree.c
fdt_ro.c
fdt_rw.c
fdt_strerror.c
fdt_sw.c
fdt_wip.c
find_bit.c	lib/find: introduce find_nth_and_andnot_bit	2023-02-07 18:20:00 -08:00
find_bit_benchmark.c	treewide: use get_random_u32_below() instead of deprecated function	2022-11-18 02:15:15 +01:00
flex_proportions.c
fortify_kunit.c	kunit/fortify: Validate __alloc_size attribute results	2022-11-22 21:08:28 -08:00
gen_crc32table.c
gen_crc64table.c
genalloc.c	lib/genalloc: use try_cmpxchg in {set,clear}_bits_ll	2023-02-02 22:50:05 -08:00
generic-radix-tree.c
glob.c
globtest.c
group_cpus.c	genirq/affinity: Only build SMP-only helper functions on SMP kernels	2023-01-18 12:16:47 +01:00
hashtable_test.c	lib/hashtable_test.c: add test for the hashtable structure	2023-02-08 14:28:17 -07:00
hexdump.c
hweight.c
idr.c
inflate.c
interval_tree.c	interval-tree: Add a utility to iterate over spans in an interval tree	2022-11-29 16:34:15 -04:00
interval_tree_test.c
iomap.c	kmsan: add iomap support	2022-10-03 14:03:21 -07:00
iomap_copy.c
iommu-helper.c
iov_iter.c	46 fs/cifs (smb3 client) changesets, 37 in fs/cifs and 9 for related helper functions and cleanup outside from Dave Howells and Willy	2023-02-22 17:12:44 -08:00
irq_poll.c
irq_regs.c
is_signed_type_kunit.c	lib: assume char is unsigned	2022-11-19 00:56:15 +01:00
is_single_threaded.c
kasprintf.c
Kconfig	iommufd for 6.2	2022-12-14 09:15:43 -08:00
Kconfig.debug	There is no particular theme here - mainly quick hits all over the tree.	2023-02-23 17:55:40 -08:00
Kconfig.kasan	kasan: treat meminstrinsic as builtins in uninstrumented files	2023-03-02 21:54:22 -08:00
Kconfig.kcsan	Kernel concurrency sanitizer (KCSAN) updates for v6.3	2023-02-25 13:02:20 -08:00
Kconfig.kfence
Kconfig.kgdb	parisc: Convert PDC console to an early console	2022-10-11 12:01:24 +02:00
Kconfig.kmsan	kmsan: make sure PREEMPT_RT is off	2022-11-08 15:57:24 -08:00
Kconfig.ubsan
kfifo.c
klist.c
kobject.c	kobject: make dynamic_kobj_ktype and kset_ktype const	2023-02-08 13:34:20 +01:00
kobject_uevent.c
kstrtox.c
kstrtox.h
libcrc32c.c
linear_ranges.c
list-test.c
list_debug.c
list_sort.c
llist.c	llist: avoid extra memory read in llist_add_batch	2022-11-18 13:55:06 -08:00
locking-selftest-hardirq.h
locking-selftest-mutex.h
locking-selftest-rlock-hardirq.h
locking-selftest-rlock-softirq.h
locking-selftest-rlock.h
locking-selftest-rsem.h
locking-selftest-rtmutex.h
locking-selftest-softirq.h
locking-selftest-spin-hardirq.h
locking-selftest-spin-softirq.h
locking-selftest-spin.h
locking-selftest-wlock-hardirq.h
locking-selftest-wlock-softirq.h
locking-selftest-wlock.h
locking-selftest-wsem.h
locking-selftest.c
lockref.c	lockref: stop doing cpu_relax in the cmpxchg loop	2023-01-13 14:35:38 -06:00
logic_iomem.c
logic_pio.c
lru_cache.c	lru_cache: remove unused lc_private, lc_set, lc_index_of	2022-11-22 19:38:39 -07:00
lshrdi3.c
Makefile	kunit: Fix 'hooks.o' build by recursing into kunit	2023-02-27 14:49:03 -08:00
maple_tree.c	maple_tree: reduce stack usage with gcc-9 and earlier	2023-02-16 20:43:55 -08:00
memcat_p.c
memcpy_kunit.c	kunit: memcpy: Split slow memcpy tests into MEMCPY_SLOW_KUNIT_TEST	2023-01-25 12:24:40 -08:00
memory-notifier-error-inject.c
memregion.c
memweight.c
muldi3.c
net_utils.c	mac_pton: Don't access memory over expected length	2022-11-09 19:28:02 -08:00
netdev-notifier-error-inject.c
nlattr.c	netlink: prevent potential spectre v1 gadgets	2023-01-20 17:52:32 -08:00
nmi_backtrace.c	x86/nmi: Print reasons why backtrace NMIs are ignored	2023-01-19 15:55:12 -08:00
notifier-error-inject.c	lib/notifier-error-inject: fix error when writing -errno to debugfs file	2022-11-30 16:13:16 -08:00
notifier-error-inject.h
objagg.c
of-reconfig-notifier-error-inject.c
oid_registry.c	lib/oid_registry.c: remove redundant assignment to variable num	2022-11-18 13:55:06 -08:00
once.c	once: rename _SLOW to _SLEEPABLE	2022-10-03 17:34:32 -07:00
overflow_kunit.c	overflow: Introduce overflows_type() and castable_to_type()	2022-11-02 12:39:27 -07:00
packing.c	lib: packing: replace bit_reverse() with bitrev8()	2022-12-12 15:06:30 -08:00
parman.c
parser.c	lib: parser: update documentation for match_NUMBER functions	2023-03-02 21:54:22 -08:00
pci_iomap.c
percpu-refcount.c	percpu-refcount: Use call_rcu_hurry() for atomic switch	2022-11-30 13:16:40 -08:00
percpu_counter.c	lib/percpu_counter: percpu_counter_add_batch() overflow/underflow	2023-02-02 22:50:01 -08:00
percpu_test.c
plist.c
pm-notifier-error-inject.c
polynomial.c
radix-tree.c	lib/radix-tree.c: fix uninitialized variable compilation warning	2022-11-30 16:13:17 -08:00
random32.c	treewide: use get_random_bytes() when possible	2022-10-11 17:42:58 -06:00
ratelimit.c
rbtree.c
rbtree_test.c
ref_tracker.c
refcount.c
rhashtable.c	rhashtable: Allow rhashtable to be used from irq-safe contexts	2022-12-09 10:42:56 +00:00
sbitmap.c	sbitmap: correct wake_batch recalculation to avoid potential IO hung	2023-01-29 20:03:01 -07:00
scatterlist.c	lib/scatterlist: Fix to calculate the last_pg properly	2023-01-16 12:08:31 -04:00
seq_buf.c
sg_pool.c
sg_split.c
show_mem.c	mm: reduce noise in show_mem for lowmem allocations	2022-09-26 19:46:29 -07:00
siphash.c
siphash_kunit.c	siphash: Convert selftest to KUnit	2022-11-01 10:04:52 -07:00
slub_kunit.c	linux-kselftest-kunit-next-6.2-rc1	2022-12-12 16:42:57 -08:00
smp_processor_id.c
sort.c
stackdepot.c	lib/stackdepot: move documentation comments to stackdepot.h	2023-02-16 20:43:52 -08:00
stackinit_kunit.c	kernel/range: Uplevel the cxl subsystem's range_contains() helper	2023-02-10 17:32:37 -08:00
stmp_device.c
string.c	lib/string: Use strchr() in strpbrk()	2023-01-27 11:42:57 -08:00
string_helpers.c
strncpy_from_user.c
strnlen_user.c
strscpy_kunit.c	fortify: Short-circuit known-safe calls to strscpy()	2022-11-01 10:04:52 -07:00
syscall.c
test-kstrtox.c
test-string_helpers.c	treewide: use get_random_u32_below() instead of deprecated function	2022-11-18 02:15:15 +01:00
test_bitmap.c	lib/bitmap: add tests for for_each() loops	2022-10-01 10:22:58 -07:00
test_bitops.c
test_bits.c
test_blackhole_dev.c
test_bpf.c	net: remove skb->vlan_present	2022-11-11 18:18:05 -08:00
test_debug_virtual.c
test_dynamic_debug.c
test_firmware.c	test_firmware: Use kstrtobool() instead of strtobool()	2023-01-20 14:09:47 +01:00
test_fprobe.c	treewide: use get_random_u32_{above,below}() instead of manual loop	2022-11-18 02:15:22 +01:00
test_fpu.c
test_free_pages.c
test_hash.c
test_hexdump.c	treewide: use get_random_u32_inclusive() when possible	2022-11-18 02:18:02 +01:00
test_hmm.c	hmm-tests: add test for migrate_device_range()	2022-10-12 18:51:50 -07:00
test_hmm_uapi.h	hmm-tests: add test for migrate_device_range()	2022-10-12 18:51:50 -07:00
test_ida.c
test_kmod.c	test_kmod: stop kernel-doc warnings	2023-01-25 14:07:21 -08:00
test_kprobes.c	test_kprobes: Add recursed kprobe test case	2023-02-21 08:52:42 +09:00
test_linear_ranges.c	lib/test_linear_ranges: Use LINEAR_RANGE()	2022-11-16 13:32:32 +00:00
test_list_sort.c	treewide: use get_random_u32_below() instead of deprecated function	2022-11-18 02:15:15 +01:00
test_lockup.c
test_maple_tree.c	test_maple_tree: test modifications while iterating	2023-02-09 16:51:31 -08:00
test_memcat_p.c
test_meminit.c	lib/test_meminit: add checks for the allocation functions	2022-10-12 18:51:49 -07:00
test_min_heap.c	treewide: use get_random_u32() when possible	2022-10-11 17:42:58 -06:00
test_module.c
test_objagg.c	treewide: use get_random_bytes() when possible	2022-10-11 17:42:58 -06:00
test_parman.c
test_printf.c	mm: discard __GFP_ATOMIC	2023-02-02 22:33:13 -08:00
test_ref_tracker.c
test_rhashtable.c	Networking changes for 6.2.	2022-12-13 15:47:48 -08:00
test_scanf.c
test_sort.c
test_static_key_base.c
test_static_keys.c
test_string.c
test_sysctl.c	testing: use the copyleft-next-0.3.1 SPDX tag	2022-11-08 15:44:02 +01:00
test_ubsan.c
test_user_copy.c
test_uuid.c
test_vmalloc.c	lib/test_vmalloc.c: add parameter use_huge for fix_size_alloc_test	2023-01-18 17:12:41 -08:00
test_xarray.c
textsearch.c
timerqueue.c
trace_readwrite.c	asm-generic/io: Add _RET_IP_ to MMIO trace for more accurate debug info	2022-11-21 22:02:10 +01:00
ts_bm.c
ts_fsm.c
ts_kmp.c
ubsan.c	hardening updates for v6.3-rc1	2023-02-21 11:07:23 -08:00
ubsan.h	arm64: Support Clang UBSAN trap codes for better reporting	2023-02-08 15:26:58 -08:00
ucmpdi2.c
ucs2_string.c
usercopy.c	uaccess: Add speculation barrier to copy_from_user()	2023-02-21 14:45:22 -08:00
uuid.c	treewide: use get_random_bytes() when possible	2022-10-11 17:42:58 -06:00
vsprintf.c	Random number generator updates for Linux 6.2-rc1.	2022-12-12 16:22:22 -08:00
win_minmax.c	lib/win_minmax: use /* notation for regular comments	2023-01-11 16:14:21 -08:00
xarray.c
xxhash.c