[v6] tcg: breakpoint reorg

[PATCH for-6.1 v6 07/17] accel/tcg: Use CF_NO_GOTO_{TB, PTR} in cpu_exec_step_atomic

Richard Henderson posted 17 patches 4 years, 6 months ago

Diff against v1 v2 v3 v4 v5
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Maintainers: Chris Wulff <crwulff@gmail.com>, Marek Vasut <marex@denx.de>, Stafford Horne <shorne@gmail.com>, Max Filippov <jcmvbkbc@gmail.com>, Richard Henderson <richard.henderson@linaro.org>, Thomas Huth <thuth@redhat.com>, Yoshinori Sato <ysato@users.sourceforge.jp>, David Gibson <david@gibson.dropbear.id.au>, Laurent Vivier <laurent@vivier.eu>, "Philippe Mathieu-Daudé" <f4bug@amsat.org>, Bin Meng <bin.meng@windriver.com>, Palmer Dabbelt <palmer@dabbelt.com>, Bastian Koppelmann <kbastian@mail.uni-paderborn.de>, Aleksandar Rikalo <aleksandar.rikalo@syrmia.com>, Artyom Tarasenko <atar4qemu@gmail.com>, Jiaxun Yang <jiaxun.yang@flygoat.com>, Aurelien Jarno <aurelien@aurel32.net>, Alistair Francis <alistair.francis@wdc.com>, Cornelia Huck <cohuck@redhat.com>, Peter Maydell <peter.maydell@linaro.org>, Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>, Michael Rolnik <mrolnik@gmail.com>, Taylor Simpson <tsimpson@quicinc.com>, "Edgar E. Iglesias" <edgar.iglesias@gmail.com>, David Hildenbrand <david@redhat.com>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Eduardo Habkost <ehabkost@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, Greg Kurz <groug@kaod.org>

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[PATCH for-6.1 v6 07/17] accel/tcg: Use CF_NO_GOTO_{TB, PTR} in cpu_exec_step_atomic

Posted by Richard Henderson 4 years, 6 months ago

Request that the one TB returns immediately, so that
we release the exclusive lock as soon as possible.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210717221851.2124573-7-richard.henderson@linaro.org>
---
 accel/tcg/cpu-exec.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
index 2206c463f5..5bb099174f 100644
--- a/accel/tcg/cpu-exec.c
+++ b/accel/tcg/cpu-exec.c
@@ -330,8 +330,7 @@ void cpu_exec_step_atomic(CPUState *cpu)
     CPUArchState *env = (CPUArchState *)cpu->env_ptr;
     TranslationBlock *tb;
     target_ulong cs_base, pc;
-    uint32_t flags;
-    uint32_t cflags = (curr_cflags(cpu) & ~CF_PARALLEL) | 1;
+    uint32_t flags, cflags;
     int tb_exit;
 
     if (sigsetjmp(cpu->jmp_env, 0) == 0) {
@@ -341,8 +340,14 @@ void cpu_exec_step_atomic(CPUState *cpu)
         cpu->running = true;
 
         cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
-        tb = tb_lookup(cpu, pc, cs_base, flags, cflags);
 
+        cflags = curr_cflags(cpu);
+        /* Execute in a serial context. */
+        cflags &= ~CF_PARALLEL;
+        /* After 1 insn, return and release the exclusive lock. */
+        cflags |= CF_NO_GOTO_TB | CF_NO_GOTO_PTR | 1;
+
+        tb = tb_lookup(cpu, pc, cs_base, flags, cflags);
         if (tb == NULL) {
             mmap_lock();
             tb = tb_gen_code(cpu, pc, cs_base, flags, cflags);
-- 
2.25.1