| Message ID | 20170915054404.19914-2-famz@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | [1/3] migration: Allow ram_save_cleanup to be called with empty state | expand |
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 <famz@redhat.com> > --- > 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()?
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 <famz@redhat.com> > > --- > > 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. Fam
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 <famz@redhat.com> > > > --- > > > 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.
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 <famz@redhat.com> > > > > --- > > > > 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. Fam
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 <famz@redhat.com> > > > > > --- > > > > > 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 <peterx@redhat.com> Thanks,
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 */
So that we can do cleanup unconditionally at the end of main(). Signed-off-by: Fam Zheng <famz@redhat.com> --- migration/ram.c | 3 +++ 1 file changed, 3 insertions(+)