From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53574) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dslWm-00067J-FZ for qemu-devel@nongnu.org; Fri, 15 Sep 2017 03:59:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dslWi-0007RA-Jf for qemu-devel@nongnu.org; Fri, 15 Sep 2017 03:59:08 -0400 Date: Fri, 15 Sep 2017 15:58:57 +0800 From: Peter Xu Message-ID: <20170915075857.GR3617@pxdev.xzpeter.org> References: <20170915054404.19914-1-famz@redhat.com> <20170915054404.19914-2-famz@redhat.com> <20170915064132.GP3617@pxdev.xzpeter.org> <20170915064907.GD17199@lemon> <20170915065627.GQ3617@pxdev.xzpeter.org> <20170915070232.GF17199@lemon> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20170915070232.GF17199@lemon> Subject: Re: [Qemu-devel] [PATCH 1/3] migration: Allow ram_save_cleanup to be called with empty state List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Fam Zheng Cc: qemu-devel@nongnu.org, "Dr. David Alan Gilbert" , Juan Quintela , qemu-stable@nongnu.org On Fri, Sep 15, 2017 at 03:02:32PM +0800, Fam Zheng wrote: > On Fri, 09/15 14:56, Peter Xu wrote: > > On Fri, Sep 15, 2017 at 02:49:07PM +0800, Fam Zheng wrote: > > > On Fri, 09/15 14:41, Peter Xu wrote: > > > > On Fri, Sep 15, 2017 at 01:44:02PM +0800, Fam Zheng wrote: > > > > > So that we can do cleanup unconditionally at the end of main(). > > > > > > > > > > Signed-off-by: Fam Zheng > > > > > --- > > > > > migration/ram.c | 3 +++ > > > > > 1 file changed, 3 insertions(+) > > > > > > > > > > diff --git a/migration/ram.c b/migration/ram.c > > > > > index e18b3e2d4f..37e6a71241 100644 > > > > > --- a/migration/ram.c > > > > > +++ b/migration/ram.c > > > > > @@ -1365,6 +1365,9 @@ static void ram_save_cleanup(void *opaque) > > > > > RAMState **rsp = opaque; > > > > > RAMBlock *block; > > > > > > > > > > + if (!rsp || !*rsp) { > > > > > + return; > > > > > + } > > > > > /* caller have hold iothread lock or is in a bh, so there is > > > > > * no writing race against this migration_bitmap > > > > > */ > > > > > -- > > > > > 2.13.5 > > > > > > > > > > > > > Instead of take special care on RAM, how about check in > > > > migrate_fd_cancel(), and return directly if migration_is_idle()? > > > > > > This is not from migrate_fd_cancel(), but from qemu_savevm_state_cleanup(), so > > > that doesn't work. > > > > Yeh I see the point. But my logic still stands - we don't need to > > cleanup anything if the migration is not really there. > > > > I'm thinking whether we can put qemu_savevm_state_cleanup() into > > migrate_fd_cancel() in some way, though I am still not 100% sure on > > the colo part. Anyway, I feel like a bit confusing we have two > > cleanup functions. > > I agree, but I don't know what is the best way to clean this up: savevm and > migration seem a little independent from each other. After a 2nd thought I think this single patch is ok, at least it allows qemu_savevm_state_cleanup() to be run without caring much about migration state. So: Reviewed-by: Peter Xu Thanks, -- Peter Xu