On Wed, 2015-12-09 at 16:28 +0000, Ian Jackson wrote: > Ian Campbell writes ("Re: [PATCH XEN v6 25/32] tools/libs/gnttab: > Extensive updates to API documentation."): > > On Wed, 2015-12-09 at 16:09 +0000, Ian Jackson wrote: > > > Is this actually true ? Normally close() on an fd does not munmap > > > anything mmapped from the fd. > > > > Uh yes, I was talking rubbish here, unless the drivers are more magic > > than > > I think they are. > > > > So what is the answer? That such memory is wasted and irrecovable until > > exec? > > I don't know. What would happen if you munmapped it ?
We discussed all this IRL and concluded after much back and forth that there is nothing we can do here other than require a call to each relevant library's _close() method by callers of fork() who do not exec but who care about the (usually modest) resources consumed by these sorts of mappings. The _close call after fork should be documented as potentially not actually achieving anything and we decided to treat this as a future bug if/when it has a real world impact by fixing. Ian. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel