linux-kernel - Re: [patch] mm, slab: faster active and free stats

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Date:   Tue, 8 Nov 2016 15:17:27 -0800
From:   Andrew Morton <akpm@...ux-foundation.org>
To:     David Rientjes <rientjes@...gle.com>
Cc:     Greg Thelen <gthelen@...gle.com>,
        Aruna Ramakrishna <aruna.ramakrishna@...cle.com>,
        Christoph Lameter <cl@...ux.com>,
        Joonsoo Kim <iamjoonsoo.kim@....com>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [patch] mm, slab: faster active and free stats

On Tue, 8 Nov 2016 15:06:45 -0800 (PST) David Rientjes <rientjes@...gle.com> wrote:

> Reading /proc/slabinfo or monitoring slabtop(1) can become very expensive
> if there are many slab caches and if there are very lengthy per-node
> partial and/or free lists.
> 
> Commit 07a63c41fa1f ("mm/slab: improve performance of gathering slabinfo
> stats") addressed the per-node full lists which showed a significant
> improvement when no objects were freed.  This patch has the same
> motivation and optimizes the remainder of the usecases where there are
> very lengthy partial and free lists.
> 
> This patch maintains per-node active_slabs (full and partial) and
> free_slabs rather than iterating the lists at runtime when reading
> /proc/slabinfo.

Are there any nice numbers you can share?