From: Sergey Fedorov <serge.fdrv@gmail.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
Sergey Fedorov <sergey.fedorov@linaro.org>
Cc: qemu-devel@nongnu.org, "Alex Bennée" <alex.bennee@linaro.org>,
patches@linaro.org, mttcg@greensocs.com,
"fred konrad" <fred.konrad@greensocs.com>,
"a rigo" <a.rigo@virtualopensystems.com>,
cota@braap.org, "bobby prani" <bobby.prani@gmail.com>,
rth@twiddle.net, "mark burton" <mark.burton@greensocs.com>,
"jan kiszka" <jan.kiszka@siemens.com>,
"peter maydell" <peter.maydell@linaro.org>,
"claudio fontana" <claudio.fontana@huawei.com>,
"Peter Crosthwaite" <crosthwaite.peter@gmail.com>
Subject: Re: [Qemu-devel] [PATCH 3/3] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump()
Date: Fri, 8 Jul 2016 13:25:01 +0300 [thread overview]
Message-ID: <577F7F7D.4010207@gmail.com> (raw)
In-Reply-To: <71295249.5198305.1467967205882.JavaMail.zimbra@redhat.com>
On 08/07/16 11:40, Paolo Bonzini wrote:
> Even better: add a "bool *tb_locked" argument to tb_find_slow, and
> don't move the mmap_lock release. Then tb_find_fast knows directly
> whether tb_lock is taken, and you don't need any of tb_lock_reset
> or mmap_lock_reset.
I think we can do even better. One option is using a separate tiny lock
to protect direct jump set/reset instead of tb_lock.
Another option which I've had in my mind for some time is to make direct
jump set/reset thread-safe. We already have thread-safe TB patching. The
only question is the right order of operations and handling
jmp_list_next/jmp_list_first safely. I think that could be done by
removing tb_remove_from_jmp_list() and making RCU-like manipulation with
jmp_list_next/jmp_list_first. What do you think?
Kind regards,
Sergey
next prev parent reply other threads:[~2016-07-08 10:25 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-05 16:18 [Qemu-devel] [PATCH v2 0/6] Reduce lock contention on TCG hot-path Alex Bennée
2016-07-05 16:18 ` [Qemu-devel] [PATCH v2 1/6] tcg: Ensure safe tb_jmp_cache lookup out of 'tb_lock' Alex Bennée
2016-07-07 13:52 ` Sergey Fedorov
2016-07-08 14:51 ` Sergey Fedorov
2016-07-05 16:18 ` [Qemu-devel] [PATCH v2 2/6] tcg: set up tb->page_addr before insertion Alex Bennée
2016-07-07 14:08 ` Sergey Fedorov
2016-07-08 9:40 ` Sergey Fedorov
2016-07-05 16:18 ` [Qemu-devel] [PATCH v2 3/6] tcg: cpu-exec: remove tb_lock from the hot-path Alex Bennée
2016-07-07 14:18 ` Sergey Fedorov
2016-07-08 15:50 ` Sergey Fedorov
2016-07-08 17:34 ` Sergey Fedorov
2016-07-08 18:03 ` Alex Bennée
2016-07-08 18:20 ` Sergey Fedorov
2016-07-08 20:09 ` Sergey Fedorov
2016-07-05 16:18 ` [Qemu-devel] [PATCH v2 4/6] tcg: cpu-exec: factor out TB patching code Alex Bennée
2016-07-05 16:18 ` [Qemu-devel] [PATCH v2 5/6] tcg: introduce tb_lock_recursive() Alex Bennée
2016-07-05 16:18 ` [Qemu-devel] [PATCH v2 6/6] tcg: cpu-exec: roll-up tb_find_fast/slow Alex Bennée
2016-07-07 16:44 ` Sergey Fedorov
2016-07-07 16:44 ` [Qemu-devel] [PATCH 1/3] tcg: Introduce mmap_lock_reset() Sergey Fedorov
2016-07-07 16:44 ` [Qemu-devel] [PATCH 2/3] tcg: Introduce tb_lock_locked() Sergey Fedorov
2016-07-07 16:44 ` [Qemu-devel] [PATCH 3/3] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump() Sergey Fedorov
2016-07-07 19:36 ` Alex Bennée
2016-07-07 19:46 ` Sergey Fedorov
2016-07-07 20:36 ` Sergey Fedorov
2016-07-07 21:40 ` Alex Bennée
2016-07-08 8:40 ` Paolo Bonzini
2016-07-08 10:25 ` Sergey Fedorov [this message]
2016-07-08 11:02 ` Paolo Bonzini
2016-07-08 12:32 ` Sergey Fedorov
2016-07-08 14:07 ` Paolo Bonzini
2016-07-08 19:55 ` Sergey Fedorov
2016-07-08 20:18 ` Paolo Bonzini
2016-07-08 20:24 ` Sergey Fedorov
2016-07-08 20:52 ` Paolo Bonzini
2016-07-11 13:06 ` Sergey Fedorov
2016-07-11 14:03 ` Paolo Bonzini
2016-07-11 14:27 ` Sergey Fedorov
2016-07-07 16:04 ` [Qemu-devel] [PATCH v2 0/6] Reduce lock contention on TCG hot-path Emilio G. Cota
2016-07-07 16:13 ` Paolo Bonzini
2016-07-07 19:33 ` Alex Bennée
2016-07-07 19:38 ` Alex Bennée
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