[PATCH 1/2] x86/tsc: Force inlining of cyc2ns bits

From: Peter Zijlstra
Date: Thu Oct 11 2018 - 06:45:28 EST


Looking at the asm for native_sched_clock() I noticed we don't inline
enough. Mostly caused by sharing code with cyc2ns_read_begin(), which
we didn't used to do. So mark all that __force_inline to make it DTRT.

Fixes: 59eaef78bfea ("x86/tsc: Remodel cyc2ns to use seqcount_latch()")
Reported-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
arch/x86/kernel/tsc.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -57,7 +57,7 @@ struct cyc2ns {

static DEFINE_PER_CPU_ALIGNED(struct cyc2ns, cyc2ns);

-void cyc2ns_read_begin(struct cyc2ns_data *data)
+void __always_inline cyc2ns_read_begin(struct cyc2ns_data *data)
{
int seq, idx;

@@ -74,7 +74,7 @@ void cyc2ns_read_begin(struct cyc2ns_dat
} while (unlikely(seq != this_cpu_read(cyc2ns.seq.sequence)));
}

-void cyc2ns_read_end(void)
+void __always_inline cyc2ns_read_end(void)
{
preempt_enable_notrace();
}
@@ -103,7 +103,7 @@ void cyc2ns_read_end(void)
* -johnstul@xxxxxxxxxx "math is hard, lets go shopping!"
*/

-static inline unsigned long long cycles_2_ns(unsigned long long cyc)
+static __always_inline unsigned long long cycles_2_ns(unsigned long long cyc)
{
struct cyc2ns_data data;
unsigned long long ns;