On 15.02.2023 17:29, Tamas K Lengyel wrote:
> On Wed, Feb 15, 2023 at 5:27 AM Jan Beulich <jbeul...@suse.com> wrote:
>> Did you consider the alternative of adjusting the ASSERT() in question
>> instead? It could reasonably become
>>
>> #ifdef CONFIG_MEM_SHARING
>> ASSERT(!p2m_is_hostp2m(p2m) || !remove_root ||
> !atomic_read(&d->shr_pages));
>> #endif
>>
>> now, I think. That would be less intrusive a change (helpful for
>> backporting), but there may be other (so far unnamed) benefits of pulling
>> ahead the shared memory teardown.
>
> I have a hard time understanding this proposed ASSERT.
It accounts for the various ways p2m_teardown() can (now) be called,
limiting the actual check for no remaining shared pages to the last
of all these invocations (on the host p2m with remove_root=true).
Maybe
/* Limit the check to the final invocation. */
if ( p2m_is_hostp2m(p2m) && remove_root )
ASSERT(!atomic_read(&d->shr_pages));
would make this easier to follow? Another option might be to move
the assertion to paging_final_teardown(), ahead of that specific call
to p2m_teardown().
Jan
