linux-kernel - Re: [PATCH 0/6] mm: Remote LRU per-cpu pagevec cache/per-cpu page list drain support

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Date:   Wed, 22 Sep 2021 13:28:17 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Vlastimil Babka <vbabka@...e.cz>
Cc:     Nicolas Saenz Julienne <nsaenzju@...hat.com>,
        akpm@...ux-foundation.org, frederic@...nel.org,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        tglx@...utronix.de, cl@...ux.com, juri.lelli@...hat.com,
        mingo@...hat.com, mtosatti@...hat.com, nilal@...hat.com,
        mgorman@...e.de, ppandit@...hat.com, williams@...hat.com,
        bigeasy@...utronix.de, anna-maria@...utronix.de,
        linux-rt-users@...r.kernel.org
Subject: Re: [PATCH 0/6] mm: Remote LRU per-cpu pagevec cache/per-cpu page
 list drain support

On Tue, Sep 21, 2021 at 07:59:51PM +0200, Vlastimil Babka wrote:

> These days the pcplist protection is done by local_lock, which solved
> the RT concerns. Probably a stupid/infeasible idea, but maybe what you
> want to achieve could be more generally solved at the local_lock level?
> That on NOHZ_FULL CPUs, local_locks could have this mode where they
> could synchronize with remote cpus?

local_lock and spinlock have different rules, local_lock for example can
never cause an irq inversion, unlike a spinlock.