linux-kernel - Re: [PATCH v5 1/2] mm: store zero pages to be swapped out in a bitmap

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAJD7tkatLV61SaZzHOw7r9+XjYsOhGn4yw78QOW-6foFiap8_g@mail.gmail.com>
Date: Fri, 14 Jun 2024 11:36:10 -0700
From: Yosry Ahmed <yosryahmed@...gle.com>
To: Usama Arif <usamaarif642@...il.com>
Cc: akpm@...ux-foundation.org, hannes@...xchg.org, shakeel.butt@...ux.dev, 
	david@...hat.com, ying.huang@...el.com, hughd@...gle.com, willy@...radead.org, 
	nphamcs@...il.com, chengming.zhou@...ux.dev, linux-mm@...ck.org, 
	linux-kernel@...r.kernel.org, kernel-team@...a.com
Subject: Re: [PATCH v5 1/2] mm: store zero pages to be swapped out in a bitmap

On Fri, Jun 14, 2024 at 3:09 AM Usama Arif <usamaarif642@...il.com> wrote:
>
> Approximately 10-20% of pages to be swapped out are zero pages [1].
> Rather than reading/writing these pages to flash resulting
> in increased I/O and flash wear, a bitmap can be used to mark these
> pages as zero at write time, and the pages can be filled at
> read time if the bit corresponding to the page is set.
> With this patch, NVMe writes in Meta server fleet decreased
> by almost 10% with conventional swap setup (zswap disabled).
>
> [1] https://lore.kernel.org/all/20171018104832epcms5p1b2232e2236258de3d03d1344dde9fce0@epcms5p1/
>
> Signed-off-by: Usama Arif <usamaarif642@...il.com>

Reviewed-by: Yosry Ahmed <yosryahmed@...gle.com>