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[PULL 05/16] tb-maint: do not use mb_read/mb_set
From: |
Paolo Bonzini |
Subject: |
[PULL 05/16] tb-maint: do not use mb_read/mb_set |
Date: |
Tue, 9 May 2023 11:04:42 +0200 |
The load side can use a relaxed load, which will surely happen before
the work item is run by async_safe_run_on_cpu() or before double-checking
under mmap_lock. The store side can use an atomic RMW operation.
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
accel/tcg/tb-maint.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/accel/tcg/tb-maint.c b/accel/tcg/tb-maint.c
index cb1f806f00d4..0dd173fbf048 100644
--- a/accel/tcg/tb-maint.c
+++ b/accel/tcg/tb-maint.c
@@ -746,7 +746,7 @@ static void do_tb_flush(CPUState *cpu, run_on_cpu_data
tb_flush_count)
tcg_region_reset_all();
/* XXX: flush processor icache at this point if cache flush is expensive */
- qatomic_mb_set(&tb_ctx.tb_flush_count, tb_ctx.tb_flush_count + 1);
+ qatomic_inc(&tb_ctx.tb_flush_count);
done:
mmap_unlock();
@@ -758,7 +758,7 @@ done:
void tb_flush(CPUState *cpu)
{
if (tcg_enabled()) {
- unsigned tb_flush_count = qatomic_mb_read(&tb_ctx.tb_flush_count);
+ unsigned tb_flush_count = qatomic_read(&tb_ctx.tb_flush_count);
if (cpu_in_exclusive_context(cpu)) {
do_tb_flush(cpu, RUN_ON_CPU_HOST_INT(tb_flush_count));
--
2.40.1
- [PULL 00/16] Misc patches for 2023-05-09, Paolo Bonzini, 2023/05/09
- [PULL 02/16] test-aio-multithread: do not use mb_read/mb_set for simple flags, Paolo Bonzini, 2023/05/09
- [PULL 01/16] rcu: remove qatomic_mb_set, expand comments, Paolo Bonzini, 2023/05/09
- [PULL 03/16] test-aio-multithread: simplify test_multi_co_schedule, Paolo Bonzini, 2023/05/09
- [PULL 04/16] call_rcu: stop using mb_set/mb_read, Paolo Bonzini, 2023/05/09
- [PULL 07/16] include/qemu/osdep.h: Bump _WIN32_WINNT to the Windows 8 API, Paolo Bonzini, 2023/05/09
- [PULL 05/16] tb-maint: do not use mb_read/mb_set,
Paolo Bonzini <=
- [PULL 09/16] target/i386: Add new EPYC CPU versions with updated cache_info, Paolo Bonzini, 2023/05/09
- [PULL 06/16] MAINTAINERS: add stanza for Kconfig files, Paolo Bonzini, 2023/05/09
- [PULL 08/16] target/i386: allow versioned CPUs to specify new cache_info, Paolo Bonzini, 2023/05/09
- [PULL 12/16] target/i386: Add missing feature bits in EPYC-Milan model, Paolo Bonzini, 2023/05/09
- [PULL 11/16] target/i386: Add feature bits for CPUID_Fn80000021_EAX, Paolo Bonzini, 2023/05/09
- [PULL 13/16] target/i386: Add VNMI and automatic IBRS feature bits, Paolo Bonzini, 2023/05/09
- [PULL 10/16] target/i386: Add a couple of feature bits in 8000_0008_EBX, Paolo Bonzini, 2023/05/09
- [PULL 16/16] meson: leave unnecessary modules out of the build, Paolo Bonzini, 2023/05/09
- [PULL 14/16] target/i386: Add EPYC-Genoa model to support Zen 4 processor series, Paolo Bonzini, 2023/05/09
- [PULL 15/16] docs: clarify --without-default-devices, Paolo Bonzini, 2023/05/09