| /* SPDX-License-Identifier: GPL-2.0 */ |
| #ifndef __LINUX_CACHE_H |
| #define __LINUX_CACHE_H |
| |
| #include <uapi/linux/kernel.h> |
| #include <asm/cache.h> |
| |
| #ifndef L1_CACHE_ALIGN |
| #define L1_CACHE_ALIGN(x) __ALIGN_KERNEL(x, L1_CACHE_BYTES) |
| #endif |
| |
| #ifndef SMP_CACHE_BYTES |
| #define SMP_CACHE_BYTES L1_CACHE_BYTES |
| #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 |
| |
| /* |
| * __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 |
| #define ____cacheline_aligned __attribute__((__aligned__(SMP_CACHE_BYTES))) |
| #endif |
| |
| #ifndef ____cacheline_aligned_in_smp |
| #ifdef CONFIG_SMP |
| #define ____cacheline_aligned_in_smp ____cacheline_aligned |
| #else |
| #define ____cacheline_aligned_in_smp |
| #endif /* CONFIG_SMP */ |
| #endif |
| |
| #ifndef __cacheline_aligned |
| #define __cacheline_aligned \ |
| __attribute__((__aligned__(SMP_CACHE_BYTES), \ |
| __section__(".data..cacheline_aligned"))) |
| #endif /* __cacheline_aligned */ |
| |
| #ifndef __cacheline_aligned_in_smp |
| #ifdef CONFIG_SMP |
| #define __cacheline_aligned_in_smp __cacheline_aligned |
| #else |
| #define __cacheline_aligned_in_smp |
| #endif /* CONFIG_SMP */ |
| #endif |
| |
| /* |
| * The maximum alignment needed for some critical structures |
| * These could be inter-node cacheline sizes/L3 cacheline |
| * size etc. Define this in asm/cache.h for your arch |
| */ |
| #ifndef INTERNODE_CACHE_SHIFT |
| #define INTERNODE_CACHE_SHIFT L1_CACHE_SHIFT |
| #endif |
| |
| #if !defined(____cacheline_internodealigned_in_smp) |
| #if defined(CONFIG_SMP) |
| #define ____cacheline_internodealigned_in_smp \ |
| __attribute__((__aligned__(1 << (INTERNODE_CACHE_SHIFT)))) |
| #else |
| #define ____cacheline_internodealigned_in_smp |
| #endif |
| #endif |
| |
| #ifndef CONFIG_ARCH_HAS_CACHE_LINE_SIZE |
| #define cache_line_size() L1_CACHE_BYTES |
| #endif |
| |
| #endif /* __LINUX_CACHE_H */ |