From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56341) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1akoo2-0003PF-Jw for qemu-devel@nongnu.org; Tue, 29 Mar 2016 04:15:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1akonx-0007Zj-Bd for qemu-devel@nongnu.org; Tue, 29 Mar 2016 04:15:18 -0400 Sender: Paolo Bonzini References: <1458815961-31979-1-git-send-email-sergey.fedorov@linaro.org> <1458815961-31979-2-git-send-email-sergey.fedorov@linaro.org> <87poukq9fk.fsf@linaro.org> <56F3F377.4070809@gmail.com> <87mvpnrkby.fsf@linaro.org> <56F4039A.5050907@redhat.com> <56F9AC4E.4070304@twiddle.net> From: Paolo Bonzini Message-ID: <56FA3981.60608@redhat.com> Date: Tue, 29 Mar 2016 10:14:57 +0200 MIME-Version: 1.0 In-Reply-To: <56F9AC4E.4070304@twiddle.net> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 1/8] tcg: Clean up direct block chaining data fields List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Richard Henderson , =?UTF-8?Q?Alex_Benn=c3=a9e?= , Sergey Fedorov Cc: sergey.fedorov@linaro.org, Peter Crosthwaite , Stefan Weil , Claudio Fontana , Alexander Graf , qemu-devel@nongnu.org, Blue Swirl , qemu-arm@nongnu.org, "Vassili Karpov (malc)" , Aurelien Jarno On 29/03/2016 00:12, Richard Henderson wrote: >> There is also a case where a TB jumps to itself; it then appears twice >> in the list with different values in the low bits, such as this: >> >> tb->jmp_list_first = tb | 0; >> .--------------------' | >> | .-------' >> tb->jmp_list_next[0] = tb | 2; > > Of course, it begs the question of why TB would be in its own list, even > if it does jump to itself. We only need the points-to list in order to > invalidate a TB and unlink it. But if TB is being invalidated, we don't > need to reset the jump within TB itself. Isn't it just because TB acts as the list head in the circular list? Or am I misunderstanding you? Paolo