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author | Alex Bennée <alex.bennee@linaro.org> | 2017-02-23 18:29:12 +0000 |
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committer | Alex Bennée <alex.bennee@linaro.org> | 2017-02-24 10:32:45 +0000 |
commit | e5143e30fb87fbf179029387f83f98a5a9b27f19 (patch) | |
tree | b328a8046041f35bc3d03611f064d5e7098c2b7f /cpu-exec.c | |
parent | 8d04fb55dec381bc5105cb47f29d918e579e8cbd (diff) | |
download | qemu-e5143e30fb87fbf179029387f83f98a5a9b27f19.zip qemu-e5143e30fb87fbf179029387f83f98a5a9b27f19.tar.gz qemu-e5143e30fb87fbf179029387f83f98a5a9b27f19.tar.bz2 |
tcg: remove global exit_request
There are now only two uses of the global exit_request left.
The first ensures we exit the run_loop when we first start to process
pending work and in the kick handler. This is just as easily done by
setting the first_cpu->exit_request flag.
The second use is in the round robin kick routine. The global
exit_request ensured every vCPU would set its local exit_request and
cause a full exit of the loop. Now the iothread isn't being held while
running we can just rely on the kick handler to push us out as intended.
We lightly re-factor the main vCPU thread to ensure cpu->exit_requests
cause us to exit the main loop and process any IO requests that might
come along. As an cpu->exit_request may legitimately get squashed
while processing the EXCP_INTERRUPT exception we also check
cpu->queued_work_first to ensure queued work is expedited as soon as
possible.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Diffstat (limited to 'cpu-exec.c')
-rw-r--r-- | cpu-exec.c | 20 |
1 files changed, 7 insertions, 13 deletions
@@ -568,15 +568,13 @@ static inline void cpu_loop_exec_tb(CPUState *cpu, TranslationBlock *tb, *tb_exit = ret & TB_EXIT_MASK; switch (*tb_exit) { case TB_EXIT_REQUESTED: - /* Something asked us to stop executing - * chained TBs; just continue round the main - * loop. Whatever requested the exit will also - * have set something else (eg exit_request or - * interrupt_request) which we will handle - * next time around the loop. But we need to - * ensure the zeroing of tcg_exit_req (see cpu_tb_exec) - * comes before the next read of cpu->exit_request - * or cpu->interrupt_request. + /* Something asked us to stop executing chained TBs; just + * continue round the main loop. Whatever requested the exit + * will also have set something else (eg interrupt_request) + * which we will handle next time around the loop. But we + * need to ensure the tcg_exit_req read in generated code + * comes before the next read of cpu->exit_request or + * cpu->interrupt_request. */ smp_mb(); *last_tb = NULL; @@ -630,10 +628,6 @@ int cpu_exec(CPUState *cpu) rcu_read_lock(); - if (unlikely(atomic_mb_read(&exit_request))) { - cpu->exit_request = 1; - } - cc->cpu_exec_enter(cpu); /* Calculate difference between guest clock and host clock. |