- 20 3月, 2023 1 次提交
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由 Dave Chinner 提交于
Equivalent of for_each_cpu_and, except it ORs the two masks together so it iterates all the CPUs present in either mask. Signed-off-by: NDave Chinner <dchinner@redhat.com> Reviewed-by: NDarrick J. Wong <djwong@kernel.org> Signed-off-by: NDarrick J. Wong <djwong@kernel.org>
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- 12 3月, 2023 1 次提交
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由 Linus Torvalds 提交于
The cpumask_check() was unnecessarily tight, and causes problems for the users of cpumask_next(). We have a number of users that take the previous return value of one of the bit scanning functions and subtract one to keep it in "range". But since the scanning functions end up returning up to 'small_cpumask_bits' instead of the tighter 'nr_cpumask_bits', the range really needs to be using that widened form. [ This "previous-1" behavior is also the reason we have all those comments about /* -1 is a legal arg here. */ and separate checks for that being ok. So we could have just made "small_cpumask_bits-1" be a similar special "don't check this" value. Tetsuo Handa even suggested a patch that only does that for cpumask_next(), since that seems to be the only actual case that triggers, but that all makes it even _more_ magical and special. So just relax the check ] One example of this kind of pattern being the 'c_start()' function in arch/x86/kernel/cpu/proc.c, but also duplicated in various forms on other architectures. Reported-by: syzbot+96cae094d90877641f32@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=96cae094d90877641f32Reported-by: NTetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Link: https://lore.kernel.org/lkml/c1f4cc16-feea-b83c-82cf-1a1f007b7eb9@I-love.SAKURA.ne.jp/ Fixes: 596ff4a0 ("cpumask: re-introduce constant-sized cpumask optimizations") Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 08 3月, 2023 1 次提交
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由 Linus Torvalds 提交于
Commit 596ff4a0 ("cpumask: re-introduce constant-sized cpumask optimizations") changed cpumask_setall() to use "bitmap_set()" instead of "bitmap_fill()", because bitmap_fill() would explicitly set all the bits of a constant sized small bitmap, and that's exactly what we don't want: we want to only set bits up to 'nr_cpu_ids', which is what "bitmap_set()" does. However, Yury correctly points out that while "bitmap_set()" does indeed only set bits up to the required bitmap size, it doesn't _clear_ bits above that size, so the upper bits would still not have well-defined values. Now, none of this should really matter, since any bits set past 'nr_cpu_ids' should always be ignored in the first place. Yes, the bit scanning functions might return them as a result, but since users should always consider the ">= nr_cpu_ids" condition to mean "no more bits", that shouldn't have any actual effect (see previous commit 8ca09d5f "cpumask: fix incorrect cpumask scanning result checks"). But let's just do it right, the way the code was _intended_ to work. We have had enough lazy code that works but bites us in the *rse later (again, see previous commit) that there's no reason to not just do this properly. It turns out that "bitmap_fill()" gets this all right for the complex case, and really only fails for the inlined optimized case that just fills the whole word. And while we could just fix bitmap_fill() to use the proper last word mask, there's two issues with that: - the cpumask case wants to do the _optimization_ based on "NR_CPUS is a small constant", but then wants to do the actual bit _fill_ based on "nr_cpu_ids" that isn't necessarily that same constant - we have lots of non-cpumask users of bitmap_fill(), and while they hopefully don't care, and probably would want the proper semantics anyway ("only set bits up to the limit"), I do not want the cpumask changes to impact other parts So this ends up just doing the single-word optimization by hand in the cpumask code. If our cpumask is fundamentally limited to a single word, just do the proper "fill in that word" exactly. And if it's the more complex multi-word case, then the generic bitmap_fill() will DTRT. This is all an example of how our bitmap function optimizations really are somewhat broken. They conflate the "this is size of the bitmap" optimizations with the actual bit(s) we want to set. In many cases we really want to have the two be separate things: sometimes we base our optimizations on the size of the whole bitmap ("I know this whole bitmap fits in a single word, so I'll just use single-word accesses"), and sometimes we base them on the bit we are looking at ("this is just acting on bits that are in the first word, so I'll use single-word accesses"). Notice how the end result of the two optimizations are the same, but the way we get to them are quite different. And all our cpumask optimization games are really about that fundamental distinction, and we'd often really want to pass in both the "this is the bit I'm working on" (which _can_ be a small constant but might be variable), and "I know it's in this range even if it's variable" (based on CONFIG_NR_CPUS). So this cpumask_setall() implementation just makes that explicit. It checks the "I statically know the size is small" using the known static size of the cpumask (which is what that 'small_cpumask_bits' is all about), but then sets the actual bits using the exact number of cpus we have (ie 'nr_cpumask_bits') Of course, in a perfect world, the compiler would have done all the range analysis (possibly with help from us just telling it that "this value is always in this range"), and would do all of this for us. But that is not the world we live in. While we dream of that perfect world, this does that manual logic to make it all work out. And this was a very long explanation for a small code change that shouldn't even matter. Reported-by: NYury Norov <yury.norov@gmail.com> Link: https://lore.kernel.org/lkml/ZAV9nGG9e1%2FrV+L%2F@yury-laptop/Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 07 3月, 2023 1 次提交
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由 Andy Shevchenko 提交于
The never used nr_cpumask_size is just a typo, hence use existing redefinition that's called nr_cpumask_bits. Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 06 3月, 2023 1 次提交
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由 Linus Torvalds 提交于
Commit aa47a7c2 ("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 6f9c07be ("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: NLinus Torvalds <torvalds@linux-foundation.org>
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- 08 2月, 2023 1 次提交
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由 Yury Norov 提交于
Introduce cpumask_nth_and_andnot() based on find_nth_and_andnot_bit(). It's used in the following patch to traverse cpumasks without storing intermediate result in temporary cpumask. Signed-off-by: NYury Norov <yury.norov@gmail.com> Acked-by: NTariq Toukan <tariqt@nvidia.com> Reviewed-by: NJacob Keller <jacob.e.keller@intel.com> Reviewed-by: NPeter Lafreniere <peter@n8pjl.ca> Signed-off-by: NJakub Kicinski <kuba@kernel.org>
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- 13 1月, 2023 1 次提交
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由 Peter Zijlstra 提交于
objtool found cases where ACPI methods called out into instrumentation code: vmlinux.o: warning: objtool: io_idle+0xc: call to __inb.isra.0() leaves .noinstr.text section vmlinux.o: warning: objtool: acpi_idle_enter+0xfe: call to num_online_cpus() leaves .noinstr.text section vmlinux.o: warning: objtool: acpi_idle_enter+0x115: call to acpi_idle_fallback_to_c1.isra.0() leaves .noinstr.text section Fix this by: marking the IO in/out, acpi_idle_fallback_to_c1() and num_online_cpus() methods as __always_inline. Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: NIngo Molnar <mingo@kernel.org> Tested-by: NTony Lindgren <tony@atomide.com> Tested-by: NUlf Hansson <ulf.hansson@linaro.org> Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: NFrederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/20230112195541.294846301@infradead.org
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- 17 10月, 2022 1 次提交
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由 Tetsuo Handa 提交于
This reverts commit 78e5a339 ("cpumask: fix checking valid cpu range"). syzbot is hitting WARN_ON_ONCE(cpu >= nr_cpumask_bits) warning at cpu_max_bits_warn() [1], for commit 78e5a339 ("cpumask: fix checking valid cpu range") is broken. Obviously that patch hits WARN_ON_ONCE() when e.g. reading /proc/cpuinfo because passing "cpu + 1" instead of "cpu" will trivially hit cpu == nr_cpumask_bits condition. Although syzbot found this problem in linux-next.git on 2022/09/27 [2], this problem was not fixed immediately. As a result, that patch was sent to linux.git before the patch author recognizes this problem, and syzbot started failing to test changes in linux.git since 2022/10/10 [3]. Andrew Jones proposed a fix for x86 and riscv architectures [4]. But [2] and [5] indicate that affected locations are not limited to arch code. More delay before we find and fix affected locations, less tested kernel (and more difficult to bisect and fix) before release. We should have inspected and fixed basically all cpumask users before applying that patch. We should not crash kernels in order to ask existing cpumask users to update their code, even if limited to CONFIG_DEBUG_PER_CPU_MAPS=y case. Link: https://syzkaller.appspot.com/bug?extid=d0fd2bf0dd6da72496dd [1] Link: https://syzkaller.appspot.com/bug?extid=21da700f3c9f0bc40150 [2] Link: https://syzkaller.appspot.com/bug?extid=51a652e2d24d53e75734 [3] Link: https://lkml.kernel.org/r/20221014155845.1986223-1-ajones@ventanamicro.com [4] Link: https://syzkaller.appspot.com/bug?extid=4d46c43d81c3bd155060 [5] Reported-by: NAndrew Jones <ajones@ventanamicro.com> Reported-by: syzbot+d0fd2bf0dd6da72496dd@syzkaller.appspotmail.com Signed-off-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Yury Norov <yury.norov@gmail.com> Cc: Borislav Petkov <bp@alien8.de> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 06 10月, 2022 1 次提交
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由 Valentin Schneider 提交于
for_each_cpu_and() is very convenient as it saves having to allocate a temporary cpumask to store the result of cpumask_and(). The same issue applies to cpumask_andnot() which doesn't actually need temporary storage for iteration purposes. Following what has been done for for_each_cpu_and(), introduce for_each_cpu_andnot(). Signed-off-by: NValentin Schneider <vschneid@redhat.com>
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- 02 10月, 2022 3 次提交
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由 Yury Norov 提交于
The range of valid CPUs is [0, nr_cpu_ids). Some cpumask functions are passed with a shifted CPU index, and for them, the valid range is [-1, nr_cpu_ids-1). Currently for those functions, we check the index against [-1, nr_cpu_ids), which is wrong. Signed-off-by: NYury Norov <yury.norov@gmail.com>
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由 Yury Norov 提交于
Add for_each_set_bit_wrap() macro and use it in for_each_cpu_wrap(). The new macro is based on __for_each_wrap() iterator, which is simpler and smaller than cpumask_next_wrap(). Signed-off-by: NYury Norov <yury.norov@gmail.com>
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由 Yury Norov 提交于
The difference between for_each_cpu() and for_each_set_bit() is that the latter uses cpumask_next() instead of find_next_bit(), and so calls cpumask_check(). This check is useless because the iterator value is not provided by user. It generates false-positives for the very last iteration of for_each_cpu(). Signed-off-by: NYury Norov <yury.norov@gmail.com>
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- 27 9月, 2022 2 次提交
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由 Yury Norov 提交于
Add cpumask_nth_{,and,andnot} as wrappers around corresponding find functions, and use it in cpumask_local_spread(). Signed-off-by: NYury Norov <yury.norov@gmail.com>
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由 Yury Norov 提交于
The function calculates Hamming weight of (bitmap1 & bitmap2). Now we have to do like this: tmp = bitmap_alloc(nbits); bitmap_and(tmp, map1, map2, nbits); weight = bitmap_weight(tmp, nbits); bitmap_free(tmp); This requires additional memory, adds pressure on alloc subsystem, and way less cache-friendly than just: weight = bitmap_weight_and(map1, map2, nbits); The following patches apply it for cpumask functions. Signed-off-by: NYury Norov <yury.norov@gmail.com>
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- 22 9月, 2022 1 次提交
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由 Phil Auld 提交于
As PAGE_SIZE is unsigned long, -1 > PAGE_SIZE when NR_CPUS <= 3. This leads to very large file sizes: topology$ ls -l total 0 -r--r--r-- 1 root root 18446744073709551615 Sep 5 11:59 core_cpus -r--r--r-- 1 root root 4096 Sep 5 11:59 core_cpus_list -r--r--r-- 1 root root 4096 Sep 5 10:58 core_id -r--r--r-- 1 root root 18446744073709551615 Sep 5 10:10 core_siblings -r--r--r-- 1 root root 4096 Sep 5 11:59 core_siblings_list -r--r--r-- 1 root root 18446744073709551615 Sep 5 11:59 die_cpus -r--r--r-- 1 root root 4096 Sep 5 11:59 die_cpus_list -r--r--r-- 1 root root 4096 Sep 5 11:59 die_id -r--r--r-- 1 root root 18446744073709551615 Sep 5 11:59 package_cpus -r--r--r-- 1 root root 4096 Sep 5 11:59 package_cpus_list -r--r--r-- 1 root root 4096 Sep 5 10:58 physical_package_id -r--r--r-- 1 root root 18446744073709551615 Sep 5 10:10 thread_siblings -r--r--r-- 1 root root 4096 Sep 5 11:59 thread_siblings_list Adjust the inequality to catch the case when NR_CPUS is configured to a small value. Fixes: 7ee951ac ("drivers/base: fix userspace break from using bin_attributes for cpumap and cpulist") Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Yury Norov <yury.norov@gmail.com> Cc: stable@vger.kernel.org Cc: feng xiangjun <fengxj325@gmail.com> Reported-by: Nfeng xiangjun <fengxj325@gmail.com> Signed-off-by: NPhil Auld <pauld@redhat.com> Signed-off-by: NYury Norov <yury.norov@gmail.com> Link: https://lore.kernel.org/r/20220906203542.1796629-1-pauld@redhat.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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- 21 9月, 2022 1 次提交
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由 Yury Norov 提交于
The size of cpumasks is hard-limited by compile-time parameter NR_CPUS, but defined at boot-time when kernel parses ACPI/DT tables, and stored in nr_cpu_ids. In many practical cases, number of CPUs for a target is known at compile time, and can be provided with NR_CPUS. In that case, compiler may be instructed to rely on NR_CPUS as on actual number of CPUs, not an upper limit. It allows to optimize many cpumask routines and significantly shrink size of the kernel image. This patch adds FORCE_NR_CPUS option to teach the compiler to rely on NR_CPUS and enable corresponding optimizations. If FORCE_NR_CPUS=y, kernel will not set nr_cpu_ids at boot, but only check that the actual number of possible CPUs is equal to NR_CPUS, and WARN if that doesn't hold. The new option is especially useful in embedded applications because kernel configurations are unique for each SoC, the number of CPUs is constant and known well, and memory limitations are typically harder. For my 4-CPU ARM64 build with NR_CPUS=4, FORCE_NR_CPUS=y saves 46KB: add/remove: 3/4 grow/shrink: 46/729 up/down: 652/-46952 (-46300) Signed-off-by: NYury Norov <yury.norov@gmail.com>
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- 20 9月, 2022 3 次提交
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由 Yury Norov 提交于
Cpumask code is written in assumption that when CONFIG_CPUMASK_OFFSTACK is enabled, all cpumasks have boot-time defined size, otherwise the size is always NR_CPUS. The latter is wrong because the number of possible cpus is always calculated on boot, and it may be less than NR_CPUS. On my 4-cpu arm64 VM the nr_cpu_ids is 4, as expected, and nr_cpumask_bits is 256, which corresponds to NR_CPUS. This not only leads to useless traversing of cpumask bits greater than 4, this also makes some cpumask routines fail. For example, cpumask_full(0b1111000..000) would erroneously return false in the example above because tail bits in the mask are all unset. This patch deprecates nr_cpumask_bits and wires it to nr_cpu_ids unconditionally, so that cpumask routines will not waste time traversing unused part of cpu masks. It also fixes cpumask_full() and similar routines. As a side effect, because now a length of cpumasks is defined at run-time even if CPUMASK_OFFSTACK is disabled, compiler can't optimize corresponding functions. It increases kernel size by ~2.5KB if OFFSTACK is off. This is addressed in the following patch. Signed-off-by: NYury Norov <yury.norov@gmail.com>
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由 Yury Norov 提交于
The comment says that HOTPLUG config option enables all cpus in cpu_possible_mask up to NR_CPUs. This is wrong. Even if HOTPLUG is enabled, the mask is populated on boot with respect to ACPI/DT records. Signed-off-by: NYury Norov <yury.norov@gmail.com>
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由 Yury Norov 提交于
In preparation to support compile-time nr_cpu_ids, add a setter for the variable. This is a no-op for all arches. Signed-off-by: NYury Norov <yury.norov@gmail.com>
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- 09 9月, 2022 1 次提交
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由 Phil Auld 提交于
As PAGE_SIZE is unsigned long, -1 > PAGE_SIZE when NR_CPUS <= 3. This leads to very large file sizes: topology$ ls -l total 0 -r--r--r-- 1 root root 18446744073709551615 Sep 5 11:59 core_cpus -r--r--r-- 1 root root 4096 Sep 5 11:59 core_cpus_list -r--r--r-- 1 root root 4096 Sep 5 10:58 core_id -r--r--r-- 1 root root 18446744073709551615 Sep 5 10:10 core_siblings -r--r--r-- 1 root root 4096 Sep 5 11:59 core_siblings_list -r--r--r-- 1 root root 18446744073709551615 Sep 5 11:59 die_cpus -r--r--r-- 1 root root 4096 Sep 5 11:59 die_cpus_list -r--r--r-- 1 root root 4096 Sep 5 11:59 die_id -r--r--r-- 1 root root 18446744073709551615 Sep 5 11:59 package_cpus -r--r--r-- 1 root root 4096 Sep 5 11:59 package_cpus_list -r--r--r-- 1 root root 4096 Sep 5 10:58 physical_package_id -r--r--r-- 1 root root 18446744073709551615 Sep 5 10:10 thread_siblings -r--r--r-- 1 root root 4096 Sep 5 11:59 thread_siblings_list Adjust the inequality to catch the case when NR_CPUS is configured to a small value. Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Yury Norov <yury.norov@gmail.com> Cc: stable@vger.kernel.org Cc: feng xiangjun <fengxj325@gmail.com> Fixes: 7ee951ac ("drivers/base: fix userspace break from using bin_attributes for cpumap and cpulist") Reported-by: Nfeng xiangjun <fengxj325@gmail.com> Signed-off-by: NPhil Auld <pauld@redhat.com> Signed-off-by: NYury Norov <yury.norov@gmail.com>
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- 16 8月, 2022 2 次提交
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由 Sander Vanheule 提交于
In the uniprocessor case, cpumask_next_wrap() can be simplified, as the number of valid argument combinations is limited: - 'start' can only be 0 - 'n' can only be -1 or 0 The only valid CPU that can then be returned, if any, will be the first one set in the provided 'mask'. For NR_CPUS == 1, include/linux/cpumask.h now provides an inline definition of cpumask_next_wrap(), which will conflict with the one provided by lib/cpumask.c. Make building of lib/cpumask.o again depend on CONFIG_SMP=y (i.e. NR_CPUS > 1) to avoid the re-definition. Suggested-by: NYury Norov <yury.norov@gmail.com> Signed-off-by: NSander Vanheule <sander@svanheule.net> Signed-off-by: NYury Norov <yury.norov@gmail.com>
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由 Sander Vanheule 提交于
Between the generic version, and their uniprocessor optimised implementations, the return types of cpumask_any_and_distribute() and cpumask_any_distribute() are not identical. Change the UP versions to 'unsigned int', to match the generic versions. Suggested-by: NYury Norov <yury.norov@gmail.com> Signed-off-by: NSander Vanheule <sander@svanheule.net> Signed-off-by: NYury Norov <yury.norov@gmail.com>
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- 18 7月, 2022 3 次提交
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由 Sander Vanheule 提交于
The extern specifier is not needed for this declaration, so drop it. The function also depends only on the input parameters, and has no side effects, so it can be marked __pure like other functions in cpumask.h. Link: https://lkml.kernel.org/r/72ab755695b74bb5fbaa756ae4c0edd708d172f1.1656777646.git.sander@svanheule.netSigned-off-by: NSander Vanheule <sander@svanheule.net> Reviewed-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Marco Elver <elver@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Valentin Schneider <vschneid@redhat.com> Cc: Yury Norov <yury.norov@gmail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
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由 Sander Vanheule 提交于
On uniprocessor builds, any CPU mask is assumed to contain exactly one CPU (cpu0). This assumption ignores the existence of empty masks, resulting in incorrect behaviour. cpumask_first_zero(), cpumask_next_zero(), and for_each_cpu_not() don't provide behaviour matching the assumption that a UP mask is always "1", and instead provide behaviour matching the empty mask. Drop the incorrectly optimised code and use the generic implementations in all cases. Link: https://lkml.kernel.org/r/86bf3f005abba2d92120ddd0809235cab4f759a6.1656777646.git.sander@svanheule.netSigned-off-by: NSander Vanheule <sander@svanheule.net> Suggested-by: NYury Norov <yury.norov@gmail.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Marco Elver <elver@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Valentin Schneider <vschneid@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
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由 Sander Vanheule 提交于
On uniprocessor builds, the following loops will always run over a mask that contains one enabled CPU (cpu0): - for_each_possible_cpu - for_each_online_cpu - for_each_present_cpu Provide uniprocessor-specific macros for these loops, that always run exactly once. Link: https://lkml.kernel.org/r/3a92869b902a075b97be5d1452c9c6badbbff0df.1656777646.git.sander@svanheule.netSigned-off-by: NSander Vanheule <sander@svanheule.net> Acked-by: NYury Norov <yury.norov@gmail.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Marco Elver <elver@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Valentin Schneider <vschneid@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
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- 15 7月, 2022 5 次提交
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由 Phil Auld 提交于
Using bin_attributes with a 0 size causes fstat and friends to return that 0 size. This breaks userspace code that retrieves the size before reading the file. Rather than reverting 75bd50fa ("drivers/base/node.c: use bin_attribute to break the size limitation of cpumap ABI") let's put in a size value at compile time. For cpulist the maximum size is on the order of NR_CPUS * (ceil(log10(NR_CPUS)) + 1)/2 which for 8192 is 20480 (8192 * 5)/2. In order to get near that you'd need a system with every other CPU on one node. For example: (0,2,4,8, ... ). To simplify the math and support larger NR_CPUS in the future we are using (NR_CPUS * 7)/2. We also set it to a min of PAGE_SIZE to retain the older behavior for smaller NR_CPUS. The cpumap file the size works out to be NR_CPUS/4 + NR_CPUS/32 - 1 (or NR_CPUS * 9/32 - 1) including the ","s. Add a set of macros for these values to cpumask.h so they can be used in multiple places. Apply these to the handful of such files in drivers/base/topology.c as well as node.c. As an example, on an 80 cpu 4-node system (NR_CPUS == 8192): before: -r--r--r--. 1 root root 0 Jul 12 14:08 system/node/node0/cpulist -r--r--r--. 1 root root 0 Jul 11 17:25 system/node/node0/cpumap after: -r--r--r--. 1 root root 28672 Jul 13 11:32 system/node/node0/cpulist -r--r--r--. 1 root root 4096 Jul 13 11:31 system/node/node0/cpumap CONFIG_NR_CPUS = 16384 -r--r--r--. 1 root root 57344 Jul 13 14:03 system/node/node0/cpulist -r--r--r--. 1 root root 4607 Jul 13 14:02 system/node/node0/cpumap The actual number of cpus doesn't matter for the reported size since they are based on NR_CPUS. Fixes: 75bd50fa ("drivers/base/node.c: use bin_attribute to break the size limitation of cpumap ABI") Fixes: bb9ec13d ("topology: use bin_attribute to break the size limitation of cpumap ABI") Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Yury Norov <yury.norov@gmail.com> Cc: stable@vger.kernel.org Acked-by: Yury Norov <yury.norov@gmail.com> (for include/linux/cpumask.h) Signed-off-by: NPhil Auld <pauld@redhat.com> Link: https://lore.kernel.org/r/20220715134924.3466194-1-pauld@redhat.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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由 Yury Norov 提交于
After moving gfp flags to a separate header, it's possible to move some cpumask allocators into headers, and avoid creating real functions. Signed-off-by: NYury Norov <yury.norov@gmail.com>
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由 Yury Norov 提交于
To avoid circular dependencies, cpumask keeps simple (almost) one-line wrappers around find_bit() in a c-file. Commit 47d8c156 ("include: move find.h from asm_generic to linux") moved find.h header out of asm_generic include path, and it helped to fix many circular dependencies, including some in cpumask.h. This patch moves those one-liners to header files. Signed-off-by: NYury Norov <yury.norov@gmail.com>
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由 Yury Norov 提交于
Switch return types to unsigned int where return values cannot be negative. Signed-off-by: NYury Norov <yury.norov@gmail.com>
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由 Yury Norov 提交于
Some cpumask functions have integer return types where return values are naturally booleans. Signed-off-by: NYury Norov <yury.norov@gmail.com>
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- 13 2月, 2022 1 次提交
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由 Borislav Petkov 提交于
Add a x86-specific cpumask_clear_cpu() helper which will be used in places where the explicit KASAN-instrumentation in the *_bit() helpers is unwanted. Also, always inline two more cpumask generic helpers. allyesconfig: text data bss dec hex filename 190553143 159425889 32076404 382055436 16c5b40c vmlinux.before 190551812 159424945 32076404 382053161 16c5ab29 vmlinux.after Signed-off-by: NBorislav Petkov <bp@suse.de> Acked-by: NMarco Elver <elver@google.com> Link: https://lore.kernel.org/r/20220204083015.17317-2-bp@alien8.de
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- 26 1月, 2022 1 次提交
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由 Borislav Petkov 提交于
Former are always inlined so do that for the latter too, for consistency. Size impact is a whopping 5 bytes increase! :-) text data bss dec hex filename 22350551 8213184 1917164 32480899 1ef9e83 vmlinux.x86-64.defconfig.before 22350556 8213152 1917164 32480872 1ef9e68 vmlinux.x86-64.defconfig.after Signed-off-by: NBorislav Petkov <bp@suse.de> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Acked-by: NMarco Elver <elver@google.com> Link: https://lore.kernel.org/r/20220113155357.4706-3-bp@alien8.de
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- 16 1月, 2022 2 次提交
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由 Yury Norov 提交于
cpumask_first() is a more effective analogue of 'next' version if n == -1 (which means start == 0). This patch replaces 'next' with 'first' where things look trivial. There's no cpumask_first_zero() function, so create it. Signed-off-by: NYury Norov <yury.norov@gmail.com> Tested-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
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由 Yury Norov 提交于
Now we have an efficient implementation for find_first_and_bit(), so switch cpumask to use it where appropriate. Signed-off-by: NYury Norov <yury.norov@gmail.com> Tested-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
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- 21 9月, 2021 1 次提交
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由 Tobias Klauser 提交于
The changes in the patch series [1] introduced a terminating null byte when reading from cpulist or cpumap sysfs files, for example: $ xxd /sys/devices/system/node/node0/cpulist 00000000: 302d 310a 00 0-1.. Before this change, the output looked as follows: $ xxd /sys/devices/system/node/node0/cpulist 00000000: 302d 310a 0-1. Fix this regression by excluding the terminating null byte from the returned length in cpumap_print_list_to_buf and cpumap_print_bitmask_to_buf. [1] https://lore.kernel.org/all/20210806110251.560-1-song.bao.hua@hisilicon.com/ Fixes: 1fae5629 ("cpumask: introduce cpumap_print_list/bitmask_to_buf to support large bitmask and list") Acked-by: NBarry Song <song.bao.hua@hisilicon.com> Acked-by: NYury Norov <yury.norov@gmail.com> Signed-off-by: NTobias Klauser <tklauser@distanz.ch> Link: https://lore.kernel.org/r/20210916222705.13554-1-tklauser@distanz.chSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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- 13 8月, 2021 1 次提交
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由 Tian Tao 提交于
The existing cpumap_print_to_pagebuf() is used by cpu topology and other drivers to export hexadecimal bitmask and decimal list to userspace by sysfs ABI. Right now, those drivers are using a normal attribute for this kind of ABIs. A normal attribute typically has show entry as below: static ssize_t example_dev_show(struct device *dev, struct device_attribute *attr, char *buf) { ... return cpumap_print_to_pagebuf(true, buf, &pmu_mmdc->cpu); } show entry of attribute has no offset and count parameters and this means the file is limited to one page only. cpumap_print_to_pagebuf() API works terribly well for this kind of normal attribute with buf parameter and without offset, count: static inline ssize_t cpumap_print_to_pagebuf(bool list, char *buf, const struct cpumask *mask) { return bitmap_print_to_pagebuf(list, buf, cpumask_bits(mask), nr_cpu_ids); } The problem is once we have many cpus, we have a chance to make bitmask or list more than one page. Especially for list, it could be as complex as 0,3,5,7,9,...... We have no simple way to know it exact size. It turns out bin_attribute is a way to break this limit. bin_attribute has show entry as below: static ssize_t example_bin_attribute_show(struct file *filp, struct kobject *kobj, struct bin_attribute *attr, char *buf, loff_t offset, size_t count) { ... } With the new offset and count parameters, this makes sysfs ABI be able to support file size more than one page. For example, offset could be >= 4096. This patch introduces cpumap_print_bitmask/list_to_buf() and their bitmap infrastructure bitmap_print_bitmask/list_to_buf() so that those drivers can move to bin_attribute to support large bitmask and list. At the same time, we have to pass those corresponding parameters such as offset, count from bin_attribute to this new API. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Stefano Brivio <sbrivio@redhat.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: "Ma, Jianpeng" <jianpeng.ma@intel.com> Cc: Yury Norov <yury.norov@gmail.com> Cc: Valentin Schneider <valentin.schneider@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Reviewed-by: NJonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: NTian Tao <tiantao6@hisilicon.com> Signed-off-by: NBarry Song <song.bao.hua@hisilicon.com> Link: https://lore.kernel.org/r/20210806110251.560-2-song.bao.hua@hisilicon.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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- 09 7月, 2021 1 次提交
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由 Zhen Lei 提交于
Fix some spelling mistakes in comments found by "codespell": Hoever ==> However poiter ==> pointer representaion ==> representation uppon ==> upon independend ==> independent aquired ==> acquired mis-match ==> mismatch scrach ==> scratch struture ==> structure Analagous ==> Analogous interation ==> iteration And some were discovered manually by Joe Perches and Christoph Lameter: stroed ==> stored arch independent ==> an architecture independent A example structure for ==> Example structure for Link: https://lkml.kernel.org/r/20210609150027.14805-2-thunder.leizhen@huawei.comSigned-off-by: NZhen Lei <thunder.leizhen@huawei.com> Cc: Christoph Lameter <cl@gentwo.de> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Dennis Zhou <dennis@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Joe Perches <joe@perches.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 16 4月, 2021 2 次提交
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由 Peter Zijlstra 提交于
Introduce a cpumask that indicates (for each CPU) what direction the CPU hotplug is currently going. Notably, it tracks rollbacks. Eg. when an up fails and we do a roll-back down, it will accurately reflect the direction. Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: NValentin Schneider <valentin.schneider@arm.com> Link: https://lkml.kernel.org/r/20210310150109.151441252@infradead.org
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由 Peter Zijlstra 提交于
Prepare for addition of another mask. Primarily a code movement to avoid having to create more #ifdef, but while there, convert everything with an argument to an inline function. Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: NValentin Schneider <valentin.schneider@arm.com> Link: https://lkml.kernel.org/r/20210310150109.045447765@infradead.org
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- 06 3月, 2021 1 次提交
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由 Nadav Amit 提交于
cpumask_next_and() and cpumask_any_but() are pure, and marking them as such seems to generate different and presumably better code for native_flush_tlb_multi(). Signed-off-by: NNadav Amit <namit@vmware.com> Signed-off-by: NIngo Molnar <mingo@kernel.org> Reviewed-by: NDave Hansen <dave.hansen@linux.intel.com> Link: https://lore.kernel.org/r/20210220231712.2475218-8-namit@vmware.com
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