linux-kernel - Re: [RFC PATCH 5/9] mm: zswap: remove zswap_same_filled_pages

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: <3e1eedef-5e4c-448f-95ea-d50b431c4265@linux.dev>
Date: Wed, 27 Mar 2024 10:44:01 +0800
From: Chengming Zhou <chengming.zhou@...ux.dev>
To: Yosry Ahmed <yosryahmed@...gle.com>,
 Andrew Morton <akpm@...ux-foundation.org>
Cc: Johannes Weiner <hannes@...xchg.org>, Nhat Pham <nphamcs@...il.com>,
 linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH 5/9] mm: zswap: remove zswap_same_filled_pages_enabled

On 2024/3/26 07:50, Yosry Ahmed wrote:
> There is no logical reason to refuse storing same-filled pages more
> efficiently and opt for compression. Remove the userspace knob.
> 
> Signed-off-by: Yosry Ahmed <yosryahmed@...gle.com>

LGTM, should we also remove zswap_non_same_filled_pages_enabled?
Not sure if it has real usage...

Reviewed-by: Chengming Zhou <chengming.zhou@...ux.dev>

> ---
>  mm/zswap.c | 11 -----------
>  1 file changed, 11 deletions(-)
> 
> diff --git a/mm/zswap.c b/mm/zswap.c
> index 498a6c5839bef..0fc27ae950c74 100644
> --- a/mm/zswap.c
> +++ b/mm/zswap.c
> @@ -123,14 +123,6 @@ static unsigned int zswap_accept_thr_percent = 90; /* of max pool size */
>  module_param_named(accept_threshold_percent, zswap_accept_thr_percent,
>  		   uint, 0644);
>  
> -/*
> - * Enable/disable handling same-value filled pages (enabled by default).
> - * If disabled every page is considered non-same-value filled.
> - */
> -static bool zswap_same_filled_pages_enabled = true;
> -module_param_named(same_filled_pages_enabled, zswap_same_filled_pages_enabled,
> -		   bool, 0644);
> -
>  /* Enable/disable handling non-same-value filled pages (enabled by default) */
>  static bool zswap_non_same_filled_pages_enabled = true;
>  module_param_named(non_same_filled_pages_enabled, zswap_non_same_filled_pages_enabled,
> @@ -1392,9 +1384,6 @@ static bool zswap_is_folio_same_filled(struct folio *folio, unsigned long *value
>  	unsigned int pos, last_pos = PAGE_SIZE / sizeof(*page) - 1;
>  	bool ret;
>  
> -	if (!zswap_same_filled_pages_enabled)
> -		return false;
> -
>  	page = kmap_local_folio(folio, 0);
>  	val = page[0];
>