Re: [PATCH] mm: avoid slub allocation while holding list_lock

[Tetsuo Handa]

Yu Zhao wrote:
> I think we can safely assume PAGE_SIZE is unsigned long aligned and
> page->objects is non-zero. But if you don't feel comfortable with these
> assumptions, I'd be happy to ensure them explicitly.

I know PAGE_SIZE is unsigned long aligned. If someone by chance happens to
change from "dynamic allocation" to "on stack", get_order() will no longer
be called and the bug will show up.

I don't know whether __get_free_page(GFP_ATOMIC) can temporarily consume more
than 4096 bytes, but if it can, we might want to avoid "dynamic allocation".

By the way, if "struct kmem_cache_node" is object which won't have many thousands
of instances, can't we embed that buffer into "struct kmem_cache_node" because
max size of that buffer is only 4096 bytes?