On Fri, Jun 17, 2022 at 09:57:06AM +0200, Vlastimil Babka wrote: > On 6/16/22 23:07, Yu Zhao wrote: > > On Thu, Jun 16, 2022 at 11:02 AM Vlastimil Babka <vbabka@xxxxxxx> wrote: > >> > >> > >> > @@ -3794,19 +3805,29 @@ static struct page *rmqueue_pcplist(struct zone *preferred_zone, > >> > struct list_head *list; > >> > struct page *page; > >> > unsigned long flags; > >> > + unsigned long __maybe_unused UP_flags; > >> > > >> > - local_lock_irqsave(&pagesets.lock, flags); > >> > + /* > >> > + * spin_trylock_irqsave is not necessary right now as it'll only be > >> > + * true when contending with a remote drain. It's in place as a > >> > + * preparation step before converting pcp locking to spin_trylock > >> > + * to protect against IRQ reentry. > >> > + */ > >> > + pcp_trylock_prepare(UP_flags); > >> > + pcp = pcp_spin_trylock_irqsave(zone->per_cpu_pageset, flags); > >> > + if (!pcp) > >> > >> Besides the missing unpin Andrew fixed, I think also this is missing > >> pcp_trylock_finish(UP_flags); ? > > > > spin_trylock only fails when trylock_finish is a NOP. > > True, so it's not an active bug, but I would still add it, so it's not > confusing and depending on non-obvious details that might later change and > break the code. Yes. Even though it may work, it's still wrong. -- Mel Gorman SUSE Labs
