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MIPS: c-r4k: Avoid small flush_icache_range SMP calls

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Avoid SMP calls for flushing small icache ranges. On non-CM platforms,
and CM platforms too after we make r4k_on_each_cpu() take the cache op
type into account, it will be called on multiple CPUs due to the
possibility that local_r4k_flush_icache_range_ipi() could do
non-globalized indexed cache ops. This rougly copies the range size
check out into r4k_flush_icache_range(), which can disallow indexed
cache ops and allow r4k_on_each_cpu() to skip the SMP call.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13805/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
James Hogan 2016-07-13 14:12:55 +01:00 committed by Ralf Baechle
parent 27b93d9c1d
commit f70ddc07b6
1 changed files with 21 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

21
arch/mips/mm/c-r4k.c
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@ -784,12 +784,33 @@ static inline void local_r4k_flush_icache_range_ipi(void *args)
static void r4k_flush_icache_range(unsigned long start, unsigned long end) static void r4k_flush_icache_range(unsigned long start, unsigned long end)
{ {
struct flush_icache_range_args args; struct flush_icache_range_args args;
unsigned long size, cache_size;
args.start = start; args.start = start;
args.end = end; args.end = end;
args.type = R4K_HIT | R4K_INDEX; args.type = R4K_HIT | R4K_INDEX;
/*
* Indexed cache ops require an SMP call.
* Consider if that can or should be avoided.
*/
preempt_disable();
if (r4k_op_needs_ipi(R4K_INDEX) && !r4k_op_needs_ipi(R4K_HIT)) {
/*
* If address-based cache ops don't require an SMP call, then
* use them exclusively for small flushes.
*/
size = start - end;
cache_size = icache_size;
if (!cpu_has_ic_fills_f_dc) {
size *= 2;
cache_size += dcache_size;
}
if (size <= cache_size)
args.type &= ~R4K_INDEX;
}
r4k_on_each_cpu(args.type, local_r4k_flush_icache_range_ipi, &args); r4k_on_each_cpu(args.type, local_r4k_flush_icache_range_ipi, &args);
preempt_enable();
instruction_hazard(); instruction_hazard();
} }