From: Christoph Lameter <cl@gentwo.de>
To: Matthew Wilcox <willy@infradead.org>
Cc: Xunlei Pang <xlpang@linux.alibaba.com>,
Vlastimil Babka <vbabka@suse.cz>,
Wen Yang <wenyang@linux.alibaba.com>,
Roman Gushchin <guro@fb.com>, Pekka Enberg <penberg@gmail.com>,
Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
David Rientjes <rientjes@google.com>,
linux-kernel@vger.kernel.org,
"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: [PATCH v2 3/3] mm/slub: Use percpu partial free counter
Date: Wed, 3 Mar 2021 20:15:58 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.22.394.2103032012250.896915@gentwo.de> (raw)
In-Reply-To: <20210303142612.GC2723601@casper.infradead.org>
On Wed, 3 Mar 2021, Matthew Wilcox wrote:
> On Tue, Mar 02, 2021 at 10:14:53AM +0100, Christoph Lameter wrote:
> > On Mon, 10 Aug 2020, Xunlei Pang wrote:
> > > - atomic_long_t partial_free_objs;
> > > + atomic_long_t __percpu *partial_free_objs;
> >
> > A percpu counter is never atomic. Just use unsigned long and use this_cpu
> > operations for this thing. That should cut down further on the overhead.
>
> What about allocations from interrupt context? Should this be a local_t
> instead?
Can this be allocated in an interrupt context?
And I am not sure how local_t relates to that? Percpu counters can be used
in an interrupt context without the overhead of the address calculations
that are required by a local_t.
next prev parent reply other threads:[~2021-03-03 21:21 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-10 12:17 [PATCH v2 0/3] mm/slub: Fix count_partial() problem Xunlei Pang
2020-08-10 12:17 ` [PATCH v2 1/3] mm/slub: Introduce two counters for partial objects Xunlei Pang
2020-08-10 12:17 ` [PATCH v2 2/3] mm/slub: Get rid of count_partial() Xunlei Pang
2020-08-10 12:17 ` [PATCH v2 3/3] mm/slub: Use percpu partial free counter Xunlei Pang
2021-03-02 5:56 ` Shu Ming
2021-03-02 9:14 ` Christoph Lameter
2021-03-03 13:46 ` Xunlei Pang
2021-03-03 14:26 ` Matthew Wilcox
2021-03-03 19:15 ` Christoph Lameter [this message]
2021-03-03 19:30 ` Matthew Wilcox
2021-03-03 19:55 ` Christoph Lameter
2021-03-03 20:16 ` Matthew Wilcox
2020-08-20 14:02 ` [PATCH v2 0/3] mm/slub: Fix count_partial() problem Pekka Enberg
2020-08-24 10:04 ` xunlei
2021-03-01 10:31 ` Shu Ming
2021-03-03 13:34 ` Xunlei Pang
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