From f70ddc07b637e8859dbdc9073fa80c95e218750d Mon Sep 17 00:00:00 2001 From: James Hogan Date: Wed, 13 Jul 2016 14:12:55 +0100 Subject: [PATCH] MIPS: c-r4k: Avoid small flush_icache_range SMP calls 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 Cc: Paul Burton Cc: Leonid Yegoshin Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13805/ Signed-off-by: Ralf Baechle --- arch/mips/mm/c-r4k.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c index cfcb336f57a0..8016babe5c84 100644 --- a/arch/mips/mm/c-r4k.c +++ b/arch/mips/mm/c-r4k.c @@ -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) { struct flush_icache_range_args args; + unsigned long size, cache_size; args.start = start; args.end = end; 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); + preempt_enable(); instruction_hazard(); } -- 2.20.1