On Fri, 2023-10-06 at 14:52 +0200, David Hildenbrand wrote:
> On 05.10.23 20:31, Vishal Verma wrote:
> >
<..>
> > @@ -2167,47 +2221,28 @@ static int __ref try_remove_memory(u64 start, u64 size)
> > if (rc)
> > return rc;
> >
> > + mem_hotplug_begin();
> > +
> > /*
> > - * We only support removing memory added with MHP_MEMMAP_ON_MEMORY in
> > - * the same granularity it was added - a single memory block.
> > + * For memmap_on_memory, the altmaps could have been added on
> > + * a per-memblock basis. Loop through the entire range if so,
> > + * and remove each memblock and its altmap.
> > */
> > if (mhp_memmap_on_memory()) {
> > - rc = walk_memory_blocks(start, size, &mem, test_has_altmap_cb);
> > - if (rc) {
> > - if (size != memory_block_size_bytes()) {
> > - pr_warn("Refuse to remove %#llx - %#llx,"
> > - "wrong granularity\n",
> > - start, start + size);
> > - return -EINVAL;
> > - }
> > - altmap = mem->altmap;
> > - /*
> > - * Mark altmap NULL so that we can add a debug
> > - * check on memblock free.
> > - */
> > - mem->altmap = NULL;
> > - }
> > + unsigned long memblock_size = memory_block_size_bytes();
> > + u64 cur_start;
> > +
> > + for (cur_start = start; cur_start < start + size;
> > + cur_start += memblock_size)
> > + remove_memory_block_and_altmap(nid, cur_start,
> > + memblock_size);
> > + } else {
> > + remove_memory_block_and_altmap(nid, start, size);
>
> Better call remove_memory_block_devices() and arch_remove_memory(start,
> size, altmap) here explicitly instead of using
> remove_memory_block_and_altmap() that really can only handle a single
> memory block with any inputs.
>
I'm not sure I follow. Even in the non memmap_on_memory case, we'd have
to walk_memory_blocks() to get to the memory_block->altmap, right?
Or is there a more direct way? If we have to walk_memory_blocks, what's
the advantage of calling those directly instead of calling the helper
created above?
Agreed with and fixed up all the other comments.
