Re: [PATCH v2 1/3] mm: fixup pfnmap memory failure handling to use pgoff

[Miaohe Lin <linmiaohe@huawei.com>]

On 2025/12/18 2:10, Ankit Agrawal wrote:
>>>        i_mmap_lock_read(mapping);
>>>        rcu_read_lock();
>>> @@ -2226,9 +2230,12 @@ static void collect_procs_pfn(struct address_space *mapping,
>>>                t = task_early_kill(tsk, true);
>>>                if (!t)
>>>                        continue;
>>> -             vma_interval_tree_foreach(vma, &mapping->i_mmap, pfn, pfn) {
>>> -                     if (vma->vm_mm == t->mm)
>>> -                             add_to_kill_pfn(t, vma, to_kill, pfn);
>>> +             vma_interval_tree_foreach(vma, &mapping->i_mmap, 0, ULONG_MAX) {
>>> +                     pgoff_t pgoff;
>>
>> IIUC, all vma will be traversed to find the final pgoff. This might not be a good idea
>> because rcu lock is held and this traversal might take a really long time. Or am I miss
>> something?
> 
> Hi Miaohe, the VMAs on the registered address space will be checked. For the nvgrace-gpu
> user of this API in 3/3, there are only 3 VMAs on the registered address space (that are
> associated with the vfio file).

Oh, I see. Thanks for your explanation. :)