On 6/16/21 8:40 PM, Yang Shi wrote:
On Wed, Jun 16, 2021 at 10:27 AM Vlastimil Babka vbabka@suse.cz wrote:
On 6/16/21 1:10 AM, Yang Shi wrote:
On Tue, Jun 15, 2021 at 5:10 AM Jann Horn jannh@google.com wrote:
It might be possible after Mel's "mm/page_alloc: Allow high-order pages to be stored on the per-cpu lists" patch (https://patchwork.kernel.org/project/linux-mm/patch/20210611135753.GC30378@t...).
Those would be percpu indeed, but not "lockless, non-atomic", no? They are protected by a local_lock.
The local_lock is *not* a lock on non-PREEMPT_RT kernel IIUC. It disables preempt and IRQ. But preempt disable is no-op on non-preempt kernel. IRQ disable can guarantee it is atomic context, but I'm not sure if it is equivalent to "atomic freelists" in Jann's context.
Hm right, I thought all locks had the acquire/release semantics, but this one is just a barrier().