diff options
Diffstat (limited to 'include/linux/cache.h')
| -rw-r--r-- | include/linux/cache.h | 129 |
1 files changed, 123 insertions, 6 deletions
diff --git a/include/linux/cache.h b/include/linux/cache.h index 4c570653ab84..e69768f50d53 100644 --- a/include/linux/cache.h +++ b/include/linux/cache.h @@ -1,23 +1,63 @@ +/* SPDX-License-Identifier: GPL-2.0 */ #ifndef __LINUX_CACHE_H #define __LINUX_CACHE_H -#include <linux/kernel.h> +#include <uapi/linux/kernel.h> +#include <vdso/cache.h> #include <asm/cache.h> #ifndef L1_CACHE_ALIGN -#define L1_CACHE_ALIGN(x) ALIGN(x, L1_CACHE_BYTES) +#define L1_CACHE_ALIGN(x) __ALIGN_KERNEL(x, L1_CACHE_BYTES) #endif -#ifndef SMP_CACHE_BYTES -#define SMP_CACHE_BYTES L1_CACHE_BYTES +/** + * SMP_CACHE_ALIGN - align a value to the L2 cacheline size + * @x: value to align + * + * On some architectures, L2 ("SMP") CL size is bigger than L1, and sometimes, + * this needs to be accounted. + * + * Return: aligned value. + */ +#ifndef SMP_CACHE_ALIGN +#define SMP_CACHE_ALIGN(x) ALIGN(x, SMP_CACHE_BYTES) +#endif + +/* + * ``__aligned_largest`` aligns a field to the value most optimal for the + * target architecture to perform memory operations. Get the actual value + * to be able to use it anywhere else. + */ +#ifndef __LARGEST_ALIGN +#define __LARGEST_ALIGN sizeof(struct { long x; } __aligned_largest) +#endif + +#ifndef LARGEST_ALIGN +#define LARGEST_ALIGN(x) ALIGN(x, __LARGEST_ALIGN) #endif +/* + * __read_mostly is used to keep rarely changing variables out of frequently + * updated cachelines. Its use should be reserved for data that is used + * frequently in hot paths. Performance traces can help decide when to use + * this. You want __read_mostly data to be tightly packed, so that in the + * best case multiple frequently read variables for a hot path will be next + * to each other in order to reduce the number of cachelines needed to + * execute a critical path. We should be mindful and selective of its use. + * ie: if you're going to use it please supply a *good* justification in your + * commit log + */ #ifndef __read_mostly #define __read_mostly #endif -#ifndef ____cacheline_aligned -#define ____cacheline_aligned __attribute__((__aligned__(SMP_CACHE_BYTES))) +/* + * __ro_after_init is used to mark things that are read-only after init (i.e. + * after mark_rodata_ro() has been called). These are effectively read-only, + * but may get written to during init, so can't live in .rodata (via "const"). + */ +#ifndef __ro_after_init +#define __ro_after_init __section(".data..ro_after_init") #endif #ifndef ____cacheline_aligned_in_smp @@ -64,4 +104,81 @@ #define cache_line_size() L1_CACHE_BYTES #endif +#ifndef __cacheline_group_begin +#define __cacheline_group_begin(GROUP) \ + __u8 __cacheline_group_begin__##GROUP[0] +#endif + +#ifndef __cacheline_group_end +#define __cacheline_group_end(GROUP) \ + __u8 __cacheline_group_end__##GROUP[0] +#endif + +/** + * __cacheline_group_begin_aligned - declare an aligned group start + * @GROUP: name of the group + * @...: optional group alignment + * + * The following block inside a struct: + * + * __cacheline_group_begin_aligned(grp); + * field a; + * field b; + * __cacheline_group_end_aligned(grp); + * + * will always be aligned to either the specified alignment or + * ``SMP_CACHE_BYTES``. + */ +#define __cacheline_group_begin_aligned(GROUP, ...) \ + __cacheline_group_begin(GROUP) \ + __aligned((__VA_ARGS__ + 0) ? : SMP_CACHE_BYTES) + +/** + * __cacheline_group_end_aligned - declare an aligned group end + * @GROUP: name of the group + * @...: optional alignment (same as was in __cacheline_group_begin_aligned()) + * + * Note that the end marker is aligned to sizeof(long) to allow more precise + * size assertion. It also declares a padding at the end to avoid next field + * falling into this cacheline. + */ +#define __cacheline_group_end_aligned(GROUP, ...) \ + __cacheline_group_end(GROUP) __aligned(sizeof(long)); \ + struct { } __cacheline_group_pad__##GROUP \ + __aligned((__VA_ARGS__ + 0) ? : SMP_CACHE_BYTES) + +#ifndef CACHELINE_ASSERT_GROUP_MEMBER +#define CACHELINE_ASSERT_GROUP_MEMBER(TYPE, GROUP, MEMBER) \ + BUILD_BUG_ON(!(offsetof(TYPE, MEMBER) >= \ + offsetofend(TYPE, __cacheline_group_begin__##GROUP) && \ + offsetofend(TYPE, MEMBER) <= \ + offsetof(TYPE, __cacheline_group_end__##GROUP))) +#endif + +#ifndef CACHELINE_ASSERT_GROUP_SIZE +#define CACHELINE_ASSERT_GROUP_SIZE(TYPE, GROUP, SIZE) \ + BUILD_BUG_ON(offsetof(TYPE, __cacheline_group_end__##GROUP) - \ + offsetofend(TYPE, __cacheline_group_begin__##GROUP) > \ + SIZE) +#endif + +/* + * Helper to add padding within a struct to ensure data fall into separate + * cachelines. + */ +#if defined(CONFIG_SMP) +struct cacheline_padding { + char x[0]; +} ____cacheline_internodealigned_in_smp; +#define CACHELINE_PADDING(name) struct cacheline_padding name +#else +#define CACHELINE_PADDING(name) +#endif + +#ifdef ARCH_DMA_MINALIGN +#define ARCH_HAS_DMA_MINALIGN +#else +#define ARCH_DMA_MINALIGN __alignof__(unsigned long long) +#endif + #endif /* __LINUX_CACHE_H */ |