From: Peter Xu <peterx@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-devel@nongnu.org, imammedo@redhat.com, richard.henderson@linaro.org
Subject: Re: [PATCH 1/8] accel: use store_release/load_acquire for cross-thread exit_request
Date: Mon, 11 Aug 2025 15:31:10 -0400 [thread overview]
Message-ID: <aJpE_owW6w31OV24@x1.local> (raw)
In-Reply-To: <20250808185905.62776-2-pbonzini@redhat.com>
On Fri, Aug 08, 2025 at 08:58:58PM +0200, Paolo Bonzini wrote:
> cpu->exit_request do not use a load-acquire/store-release pair right now,
> but this means that cpu_exit() does not store it after any flags that are
> read in the slow path.
>
> Probably everything is protected one way or the other by the BQL, because
> after reading cpu->exit_request the CPU thread often goes to sleep
> (by waiting on the BQL-protected cpu->halt_cond), but it's not clear.
> Use load-acquire/store-release consistently.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
--
Peter Xu
next prev parent reply other threads:[~2025-08-11 19:33 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-08 18:58 [PATCH 0/8] accel, cpus: clean up cpu->exit_request Paolo Bonzini
2025-08-08 18:58 ` [PATCH 1/8] accel: use store_release/load_acquire for cross-thread exit_request Paolo Bonzini
2025-08-09 22:41 ` Richard Henderson
2025-08-11 19:31 ` Peter Xu [this message]
2025-08-08 18:58 ` [PATCH 2/8] accel/hvf: check exit_request before running the vCPU Paolo Bonzini
2025-08-08 21:28 ` Philippe Mathieu-Daudé
2025-08-09 23:09 ` Richard Henderson
2025-08-11 7:06 ` Paolo Bonzini
2025-08-08 18:59 ` [PATCH 3/8] accel: use atomic accesses for exit_request Paolo Bonzini
2025-08-08 21:04 ` Philippe Mathieu-Daudé
2025-08-09 23:10 ` Richard Henderson
2025-08-11 14:49 ` Alex Bennée
2025-08-11 19:33 ` Peter Xu
2025-08-08 18:59 ` [PATCH 4/8] accel/tcg: introduce tcg_kick_vcpu_thread Paolo Bonzini
2025-08-08 21:15 ` Philippe Mathieu-Daudé
2025-08-09 23:16 ` Richard Henderson
2025-08-09 23:26 ` Richard Henderson
2025-08-11 6:10 ` Paolo Bonzini
2025-08-11 8:33 ` Philippe Mathieu-Daudé
2025-08-11 13:34 ` Philippe Mathieu-Daudé
2025-08-08 18:59 ` [PATCH 5/8] cpus: remove TCG-ism from cpu_exit() Paolo Bonzini
2025-08-08 21:17 ` Philippe Mathieu-Daudé
2025-08-09 23:17 ` Richard Henderson
2025-08-08 18:59 ` [PATCH 6/8] cpus: properly kick CPUs out of inner execution loop Paolo Bonzini
2025-08-11 12:56 ` Alex Bennée
2025-08-08 18:59 ` [PATCH 7/8] tcg/user: do not set exit_request gratuitously Paolo Bonzini
2025-08-08 21:21 ` Philippe Mathieu-Daudé
2025-08-08 21:45 ` Paolo Bonzini
2025-08-08 18:59 ` [PATCH 8/8] accel: make all calls to qemu_wait_io_event look the same Paolo Bonzini
2025-08-08 21:24 ` Philippe Mathieu-Daudé
2025-08-09 23:34 ` Richard Henderson
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