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

[Wei Wang <wei.w.wang@intel.com>]

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 <wei.w.wang@intel.com>
>> CC: Dr. David Alan Gilbert <dgilbert@redhat.com>
>> CC: Juan Quintela <quintela@redhat.com>
>> CC: Michael S. Tsirkin <mst@redhat.com>
>> CC: Peter Xu <peterx@redhat.com>
>> ---
> [...]
>
>> +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