| Message ID | 20180531051641.8473-2-peterx@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | monitor: enable OOB by default | expand |
On 05/31/2018 12:16 AM, Peter Xu wrote: > Out-Of-Band handlers need to protect shared state if there is any. > Mention it in the document. > > Suggested-by: Markus Armbruster <armbru@redhat.com> > Signed-off-by: Peter Xu <peterx@redhat.com> > --- > docs/devel/qapi-code-gen.txt | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/docs/devel/qapi-code-gen.txt b/docs/devel/qapi-code-gen.txt > index b9b6eabd08..aafc15f100 100644 > --- a/docs/devel/qapi-code-gen.txt > +++ b/docs/devel/qapi-code-gen.txt > @@ -680,6 +680,9 @@ OOB command handlers must satisfy the following conditions: > - It does not invoke system calls that may block, > - It does not access guest RAM that may block when userfaultfd is > enabled for postcopy live migration. > +- It needs to protect possilbe shared states, since as long as a s/possilbe/possible/ s/states/state/ or even 'protect any shared state' > + command supports Out-Of-Band it means the handler can be run in > + parallel with the same handler running in the other thread. > > If in doubt, do not implement OOB execution support. > >
On Thu, May 31, 2018 at 09:06:05AM -0500, Eric Blake wrote: > On 05/31/2018 12:16 AM, Peter Xu wrote: > > Out-Of-Band handlers need to protect shared state if there is any. > > Mention it in the document. > > > > Suggested-by: Markus Armbruster <armbru@redhat.com> > > Signed-off-by: Peter Xu <peterx@redhat.com> > > --- > > docs/devel/qapi-code-gen.txt | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/docs/devel/qapi-code-gen.txt b/docs/devel/qapi-code-gen.txt > > index b9b6eabd08..aafc15f100 100644 > > --- a/docs/devel/qapi-code-gen.txt > > +++ b/docs/devel/qapi-code-gen.txt > > @@ -680,6 +680,9 @@ OOB command handlers must satisfy the following conditions: > > - It does not invoke system calls that may block, > > - It does not access guest RAM that may block when userfaultfd is > > enabled for postcopy live migration. > > +- It needs to protect possilbe shared states, since as long as a > > s/possilbe/possible/ > s/states/state/ > > or even 'protect any shared state' Fixed.
diff --git a/docs/devel/qapi-code-gen.txt b/docs/devel/qapi-code-gen.txt index b9b6eabd08..aafc15f100 100644 --- a/docs/devel/qapi-code-gen.txt +++ b/docs/devel/qapi-code-gen.txt @@ -680,6 +680,9 @@ OOB command handlers must satisfy the following conditions: - It does not invoke system calls that may block, - It does not access guest RAM that may block when userfaultfd is enabled for postcopy live migration. +- It needs to protect possilbe shared states, since as long as a + command supports Out-Of-Band it means the handler can be run in + parallel with the same handler running in the other thread. If in doubt, do not implement OOB execution support.
Out-Of-Band handlers need to protect shared state if there is any. Mention it in the document. Suggested-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Peter Xu <peterx@redhat.com> --- docs/devel/qapi-code-gen.txt | 3 +++ 1 file changed, 3 insertions(+)