On 14.05.25 11:12, Igor Mammedov wrote:
On Tue, 13 May 2025 15:12:11 +0200
David Hildenbrand <da...@redhat.com> wrote:
On 13.05.25 14:13, Igor Mammedov wrote:
On Mon, 3 Mar 2025 13:02:17 -0500
yuanminghao <yuanm...@chinatelecom.cn> wrote:
Global used_memslots or used_shared_memslots is updated to 0 unexpectly
it shouldn't be 0 in practice, as it comes from number of RAM regions VM has.
It's likely a bug somewhere else.
I haven't touched this code for a long time, but I'd say if we consider multiple
devices, we shouldn't do following:
static void vhost_commit(MemoryListener *listener)
...
if (dev->vhost_ops->vhost_backend_no_private_memslots &&
dev->vhost_ops->vhost_backend_no_private_memslots(dev)) {
used_shared_memslots = dev->mem->nregions;
} else {
used_memslots = dev->mem->nregions;
}
where value dev->mem->nregions gets is well hidden/obscured
and hard to trace where tail ends => fragile.
CCing David (accidental victim) who rewrote this part the last time,
perhaps he can suggest a better way to fix the issue.
I think the original idea is that all devices (of on type: private vs.
non-private memslots) have the same number of memslots.
This avoids having to loop over all devices to figure out the number of
memslots.
... but in vhost_get_free_memslots() we already loop over all devices.
The check in vhost_dev_init() needs to be taken care of.
So maybe we can get rid of both variables completely?
looks reasonable to me, (instead of current state which is
juggling with dev->mem->nregions that can become 0 on unplug
as it was reported).
David,
do you have time to fix it?
I can try, but I was wondering/hoping whether Yuanminghao could take a
look at that? I can provide guidance if necessary.
--
Cheers,
David / dhildenb
