Re: [PATCH v7 4/6] memory: Add sanity check in address_space_to_flatview

[Peter Xu]

On Fri, Mar 10, 2023 at 10:24:23AM +0800, Chuang Xu wrote:
> Before using any flatview, sanity check whether BQL or rcu is held. And
> if we're during a memory region transaction, try to immediately update
> mappings, or the map can be invalid.

Sorry I didn't read into details in the previous version.  This subject and
commit message all need update.  It's not only about sanity anymore.

We need to state the major change to address_space_to_flatview() to allow
triggering do_commit() during a very large memory transaction, also on why
you did it.

IMHO it's because we find it's beneficial for speeding up vm load if wrap
the vm load into a whole memory transaction.  The whole point is vm load
contains far more memory updates than referencing to a specific address
space / flatview, hence this nested do_commit should logically only be
triggered in a few spots during vm load.

Thanks,

-- 
Peter Xu