Following the latest netdev trend, i.e. effective and usage-based field
cacheline placement, add helpers to group and then assert struct fields
by cachelines.
For 64-bit with 64-byte cachelines, the assertions are more strict as
the size can then be easily predicted. For the rest, just make sure
they don't cross the specified bound.
Signed-off-by: Alexander Lobakin <aleksander.loba...@intel.com>
---
include/net/libeth/cache.h | 64 ++++++++++++++++++++++++++++++++++++++
1 file changed, 64 insertions(+)
create mode 100644 include/net/libeth/cache.h
diff --git a/include/net/libeth/cache.h b/include/net/libeth/cache.h
new file mode 100644
index 000000000000..3245a20b22d3
--- /dev/null
+++ b/include/net/libeth/cache.h
@@ -0,0 +1,64 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright (C) 2024 Intel Corporation */
+
+#ifndef __LIBETH_CACHE_H
+#define __LIBETH_CACHE_H
+
+#include <linux/cache.h>
+
+/* __aligned_largest is architecture-dependent. Get the actual alignment */
+#define ___LIBETH_LARGEST_ALIGN
\
+ sizeof(struct { long __UNIQUE_ID(long_); } __aligned_largest)
+#define __LIBETH_LARGEST_ALIGN \
+ (___LIBETH_LARGEST_ALIGN > SMP_CACHE_BYTES ? \
+ ___LIBETH_LARGEST_ALIGN : SMP_CACHE_BYTES)
+#define __LIBETH_LARGEST_ALIGNED(sz) \
+ ALIGN(sz, __LIBETH_LARGEST_ALIGN)
+
+#define __libeth_cacheline_group_begin(grp) \
+ __cacheline_group_begin(grp) __aligned(__LIBETH_LARGEST_ALIGN)
+#define __libeth_cacheline_group_end(grp) \
+ __cacheline_group_end(grp) __aligned(4)
+
+#define libeth_cacheline_group(grp, ...) \
+ struct_group(grp, \
+ __libeth_cacheline_group_begin(grp); \
+ __VA_ARGS__ \
+ __libeth_cacheline_group_end(grp); \
+ )
+
+#if defined(CONFIG_64BIT) && L1_CACHE_BYTES == 64
+#define libeth_cacheline_group_assert(type, grp, sz) \
+ static_assert(offsetof(type, __cacheline_group_end__##grp) - \
+ offsetofend(type, __cacheline_group_begin__##grp) == \
+ (sz))
+#define __libeth_cacheline_struct_assert(type, sz) \
+ static_assert(sizeof(type) == (sz))
+#else /* !CONFIG_64BIT || L1_CACHE_BYTES != 64 */
+#define libeth_cacheline_group_assert(type, grp, sz) \
+ static_assert(offsetof(type, __cacheline_group_end__##grp) - \
+ offsetofend(type, __cacheline_group_begin__##grp) <= \
+ (sz))
+#define __libeth_cacheline_struct_assert(type, sz) \
+ static_assert(sizeof(type) <= (sz))
+#endif /* !CONFIG_64BIT || L1_CACHE_BYTES != 64 */
+
+#define __libeth_cls1(sz1) \
+ __LIBETH_LARGEST_ALIGNED(sz1)
+#define __libeth_cls2(sz1, sz2)
\
+ (__LIBETH_LARGEST_ALIGNED(sz1) + __LIBETH_LARGEST_ALIGNED(sz2))
+#define __libeth_cls3(sz1, sz2, sz3) \
+ (__LIBETH_LARGEST_ALIGNED(sz1) + __LIBETH_LARGEST_ALIGNED(sz2) + \
+ __LIBETH_LARGEST_ALIGNED(sz3))
+#define __libeth_cls(...) \
+ CONCATENATE(__libeth_cls, COUNT_ARGS(__VA_ARGS__))(__VA_ARGS__)
+#define libeth_cacheline_struct_assert(type, ...) \
+ __libeth_cacheline_struct_assert(type, __libeth_cls(__VA_ARGS__))
+
+#define libeth_cacheline_set_assert(type, ro, rw, c) \
+ libeth_cacheline_group_assert(type, read_mostly, ro); \
+ libeth_cacheline_group_assert(type, read_write, rw); \
+ libeth_cacheline_group_assert(type, cold, c); \
+ libeth_cacheline_struct_assert(type, ro, rw, c)
+
+#endif /* __LIBETH_CACHE_H */
--
2.45.0
