linux-kernel - Re: [PATCH v3] mm: add thp_utilization metrics to /proc/thp

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Message-ID: <6210179C-4DF8-4C32-9735-3EB1495CDB3D@oracle.com>
Date:   Fri, 5 Aug 2022 21:14:18 +0000
From:   William Kucharski <william.kucharski@...cle.com>
To:     "alexlzhu@...com" <alexlzhu@...com>
CC:     "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "kernel-team@...com" <kernel-team@...com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>
Subject: Re: [PATCH v3] mm: add thp_utilization metrics to
 /proc/thp_utilization

(My apologies if you've seen this twice, I'm having mailer issues today.)

> On Aug 5, 2022, at 12:40, alexlzhu@...com wrote:
> 
> From: Alexander Zhu <alexlzhu@...com>
> 
> This change introduces a tool that scans through all of physical
> memory for anonymous THPs and groups them into buckets based
> on utilization.

Out of curiosity, do you have any statistics on how much of a performance impact scanning may have?

We've reached the point where we've finally been able to show previous admonitions to not enable THP due to a negative performance impact no longer hold true, and I'd hate to see systems on which enabling THP now would cause a performance hit due to this scanner.