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linux-next/arch/arm/include/asm/cache.h
Russell King daf8741675 ARM: implement support for read-mostly sections
As our SMP implementation uses MESI protocols.  Grouping together data
which is mostly only read together means that we avoid unnecessary
cache line bouncing when this code shares a cache line with other data.

In other words, cache lines associated with read-mostly data are
expected to spend most of their time in shared state.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-12-05 08:39:36 +00:00

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C

/*
* arch/arm/include/asm/cache.h
*/
#ifndef __ASMARM_CACHE_H
#define __ASMARM_CACHE_H
#define L1_CACHE_SHIFT CONFIG_ARM_L1_CACHE_SHIFT
#define L1_CACHE_BYTES (1 << L1_CACHE_SHIFT)
/*
* Memory returned by kmalloc() may be used for DMA, so we must make
* sure that all such allocations are cache aligned. Otherwise,
* unrelated code may cause parts of the buffer to be read into the
* cache before the transfer is done, causing old data to be seen by
* the CPU.
*/
#define ARCH_DMA_MINALIGN L1_CACHE_BYTES
/*
* With EABI on ARMv5 and above we must have 64-bit aligned slab pointers.
*/
#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5)
#define ARCH_SLAB_MINALIGN 8
#endif
#define __read_mostly __attribute__((__section__(".data..read_mostly")))
#endif