* [PATCH] parisc: Avoid calling SMP cache flush functions on cache-less machines
@ 2022-03-12 20:05 Helge Deller
2022-03-14 19:31 ` Sven Schnelle
0 siblings, 1 reply; 2+ messages in thread
From: Helge Deller @ 2022-03-12 20:05 UTC (permalink / raw)
To: linux-parisc; +Cc: James Bottomley, John David Anglin
At least the qemu virtual machine does not provide D- and I-caches,
so skip triggering SMP irqs to flush caches on such machines.
Signed-off-by: Helge Deller <deller@gmx.de>
---
arch/parisc/kernel/cache.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c
index 81f36d6407f0..29839550146b 100644
--- a/arch/parisc/kernel/cache.c
+++ b/arch/parisc/kernel/cache.c
@@ -62,12 +62,14 @@ static struct pdc_btlb_info btlb_info __ro_after_init;
void
flush_data_cache(void)
{
- on_each_cpu(flush_data_cache_local, NULL, 1);
+ if (cache_info.dc_size)
+ on_each_cpu(flush_data_cache_local, NULL, 1);
}
void
flush_instruction_cache(void)
{
- on_each_cpu(flush_instruction_cache_local, NULL, 1);
+ if (cache_info.ic_size)
+ on_each_cpu(flush_instruction_cache_local, NULL, 1);
}
#endif
@@ -524,7 +526,8 @@ static void cacheflush_h_tmp_function(void *dummy)
void flush_cache_all(void)
{
- on_each_cpu(cacheflush_h_tmp_function, NULL, 1);
+ if (cache_info.dc_size | cache_info.ic_size)
+ on_each_cpu(cacheflush_h_tmp_function, NULL, 1);
}
static inline unsigned long mm_total_size(struct mm_struct *mm)
--
2.34.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] parisc: Avoid calling SMP cache flush functions on cache-less machines
2022-03-12 20:05 [PATCH] parisc: Avoid calling SMP cache flush functions on cache-less machines Helge Deller
@ 2022-03-14 19:31 ` Sven Schnelle
0 siblings, 0 replies; 2+ messages in thread
From: Sven Schnelle @ 2022-03-14 19:31 UTC (permalink / raw)
To: Helge Deller; +Cc: linux-parisc, James Bottomley, John David Anglin
Hi Helge,
Helge Deller <deller@gmx.de> writes:
> At least the qemu virtual machine does not provide D- and I-caches,
> so skip triggering SMP irqs to flush caches on such machines.
>
> Signed-off-by: Helge Deller <deller@gmx.de>
Not sure about the real performance benefit on hppa, but maybe use
static branches?
^ permalink raw reply [flat|nested] 2+ messages in thread
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