Re: [Qemu-devel] [PATCH v10 4/7] migration: API to clear bits of guest free pages from the dirty bitmap

[Wei Wang]

On 12/03/2018 01:10 PM, Peter Xu wrote:
> On Mon, Dec 03, 2018 at 10:18:28AM +0800, Wei Wang wrote:
> > This patch adds an API to clear bits corresponding to guest free pages
> > from the dirty bitmap. Spilt the free page block if it crosses the QEMU
> > RAMBlock boundary.
> >
> > Signed-off-by: Wei Wang <address@hidden>
> > CC: Dr. David Alan Gilbert <address@hidden>
> > CC: Juan Quintela <address@hidden>
> > CC: Michael S. Tsirkin <address@hidden>
> > CC: Peter Xu <address@hidden>
> > ---
> [...]
>
> > +void qemu_guest_free_page_hint(void *addr, size_t len)
> > +{
> > +    RAMBlock *block;
> > +    ram_addr_t offset;
> > +    size_t used_len, start, npages;
> > +    MigrationState *s = migrate_get_current();
> > +
> > +    /* This function is currently expected to be used during live migration */
> > +    if (!migration_is_setup_or_active(s->state)) {
> > +        return;
> > +    }
> > +
> > +    for (; len > 0; len -= used_len, addr += used_len) {
> > +        block = qemu_ram_block_from_host(addr, false, &offset);
> > +        if (unlikely(!block || offset > block->used_length)) {
> Maybe >=?  My fault if it is...

It would not cause problems (npages will be 0 below),
but I agree it sounds better to have ">=" earlier here. Thanks!
No problem, I can post another new version.


Best,
Wei