From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58750) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1adZFl-0000t3-Ls for qemu-devel@nongnu.org; Wed, 09 Mar 2016 03:13:58 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1adZFi-0002KH-ER for qemu-devel@nongnu.org; Wed, 09 Mar 2016 03:13:57 -0500 References: <1457074461-14285-1-git-send-email-bharata@linux.vnet.ibm.com> <1457074461-14285-2-git-send-email-bharata@linux.vnet.ibm.com> <56DDAB14.8020507@redhat.com> <20160309075710.GE29692@in.ibm.com> From: Thomas Huth Message-ID: <56DFDB2F.2030409@redhat.com> Date: Wed, 9 Mar 2016 09:13:35 +0100 MIME-Version: 1.0 In-Reply-To: <20160309075710.GE29692@in.ibm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC PATCH v1 01/10] exec: Remove cpu from cpus list during cpu_exec_exit() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: bharata@linux.vnet.ibm.com Cc: mjrosato@linux.vnet.ibm.com, agraf@suse.de, pkrempa@redhat.com, ehabkost@redhat.com, aik@ozlabs.ru, qemu-devel@nongnu.org, armbru@redhat.com, borntraeger@de.ibm.com, qemu-ppc@nongnu.org, pbonzini@redhat.com, imammedo@redhat.com, mdroth@linux.vnet.ibm.com, afaerber@suse.de, david@gibson.dropbear.id.au On 09.03.2016 08:57, Bharata B Rao wrote: > On Mon, Mar 07, 2016 at 05:23:48PM +0100, Thomas Huth wrote: >> On 04.03.2016 07:54, Bharata B Rao wrote: >>> CPUState *cpu gets added to the cpus list during cpu_exec_init(). It >>> should be removed from cpu_exec_exit(). >>> >>> cpu_exec_init() is called from generic CPU::instance_finalize and some >> >> s/cpu_exec_init/cpu_exec_exit/ >> >>> archs like PowerPC call it from CPU unrealizefn. So ensure that we >>> dequeue the cpu only once. >>> >>> Now -1 value for cpu->cpu_index indicates that we have already dequeued >>> the cpu for CONFIG_USER_ONLY case also. >>> >>> Signed-off-by: Bharata B Rao >>> --- >>> exec.c | 32 ++++++++++++++++++++++++-------- >>> 1 file changed, 24 insertions(+), 8 deletions(-) >>> >>> diff --git a/exec.c b/exec.c >>> index c62c439..7c3f747 100644 >>> --- a/exec.c >>> +++ b/exec.c >>> @@ -588,15 +588,9 @@ static int cpu_get_free_index(Error **errp) >>> return cpu; >>> } >>> >>> -void cpu_exec_exit(CPUState *cpu) >>> +static void cpu_release_index(CPUState *cpu) >>> { >>> - if (cpu->cpu_index == -1) { >>> - /* cpu_index was never allocated by this @cpu or was already freed. */ >>> - return; >>> - } >>> - >>> bitmap_clear(cpu_index_map, cpu->cpu_index, 1); >>> - cpu->cpu_index = -1; >>> } >>> #else >>> >>> @@ -611,11 +605,33 @@ static int cpu_get_free_index(Error **errp) >>> return cpu_index; >>> } >>> >>> -void cpu_exec_exit(CPUState *cpu) >>> +static void cpu_release_index(CPUState *cpu) >>> { >>> + return; >> >> You could also simply leave that return statement away, I think. >> >>> } >>> #endif >>> >>> +void cpu_exec_exit(CPUState *cpu) >>> +{ >>> +#if defined(CONFIG_USER_ONLY) >>> + cpu_list_lock(); >>> +#endif >>> + if (cpu->cpu_index == -1) { >>> + /* cpu_index was never allocated by this @cpu or was already freed. */ >>> +#if defined(CONFIG_USER_ONLY) >>> + cpu_list_unlock(); >>> +#endif >>> + return; >>> + } >>> + >>> + QTAILQ_REMOVE(&cpus, cpu, node); >>> + cpu_release_index(cpu); >>> + cpu->cpu_index = -1; >>> +#if defined(CONFIG_USER_ONLY) >>> + cpu_list_unlock(); >>> +#endif >>> +} >> >> Since there are a couple of these >> >> #if defined(CONFIG_USER_ONLY) >> cpu_list_[un]lock(); >> #endif >> >> in exec.c already, it might be somewhat nices to declare them at the >> beginning of the file as empty functions, somewhat like: >> >> #if !defined(CONFIG_USER_ONLY) >> static inline void cpu_list_lock(void) >> { >> } >> static inline void cpu_list_unlock(void) >> { >> } >> #endif >> >> What do you think about that? > > If you and/or the maintainer insist/prefer, I can make the change. It would be a nice way to get rid of some #if statements in the code, but I don't insist on that change ... so feel free to keep the current state, if you prefer it. Thomas