On 09/24/2016 04:51 AM, Paolo Bonzini wrote:
----- Original Message -----
From: "Richard Henderson" <[email protected]>
To: "Paolo Bonzini" <[email protected]>, [email protected]
Cc: "serge fdrv" <[email protected]>, [email protected], "alex bennee"
<[email protected]>, "sergey fedorov"
<[email protected]>
Sent: Friday, September 23, 2016 8:06:09 PM
Subject: Re: [Qemu-devel] [PATCH 15/16] tcg: Make tb_flush() thread safe
On 09/23/2016 12:31 AM, Paolo Bonzini wrote:
+ unsigned tb_flush_req = (unsigned) (uintptr_t) data;
Extra cast?
- tcg_ctx.tb_ctx.tb_flush_count++;
+ atomic_inc(&tcg_ctx.tb_ctx.tb_flush_count);
Since this is the only place this value is incremented, and we're under a
lock,
it should be cheaper to use
atomic_mb_set(&tcg_ctx.tb_ctx.tb_flush_count, tb_flush_req + 1);
atomic_set will do even. Though it's not really a fast path, which is
why I went for atomic_inc.
Don't we need the flush to be complete before the new count is seen? That's
why I was suggesting the mb_set.
r~
