linux-kernel - Re: [PATCH v5 00/21] mm/zsmalloc: add zpdesc memory descriptor for zswap.zpool

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 for Android: free password hash cracker in your pocket

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

Message-ID: <e99b33ad-4345-438f-9273-922d40c5ef40@gmail.com>
Date: Wed, 7 Aug 2024 15:21:56 +0800
From: Alex Shi <seakeel@...il.com>
To: Sergey Senozhatsky <senozhatsky@...omium.org>,
 Yosry Ahmed <yosryahmed@...gle.com>, Matthew Wilcox <willy@...radead.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>, alexs@...nel.org,
 Vitaly Wool <vitaly.wool@...sulko.com>, Miaohe Lin <linmiaohe@...wei.com>,
 linux-kernel@...r.kernel.org, linux-mm@...ck.org, minchan@...nel.org,
 david@...hat.com, 42.hyeyoo@...il.com, nphamcs@...il.com
Subject: Re: [PATCH v5 00/21] mm/zsmalloc: add zpdesc memory descriptor for
 zswap.zpool



On 8/7/24 1:17 PM, Sergey Senozhatsky wrote:
> On (24/08/06 12:34), Yosry Ahmed wrote:
> [..]
>>> So the sole reason for this work is as a part of the mem_desc
>>> conversion.  I'd like to hear from others who are to be involved in
>>> that conversion, please - it this patchset something we should be
>>> merging?
>>>
>>
>> Matthew asked an important question here that needs to be answered by
>> zsmalloc experts:
>> https://lore.kernel.org/lkml/Zq0zucMFsOwATsAC@casper.infradead.org/
> 
> Iff "zsmalloc experts" include me: I was under impression that there was
> a zsmalloc conversion plan otherwise this zpdesc effort is a little
> confusing, and, frankly, it hasn't appeared to me that this is "my problem"
> now.
> 
>> Do you allocate a per-page struct zpdesc, and have each one pointing
>> to a zspage?
> 
> I'm not very knowledgeable when it comes to memdesc, excuse my
> ignorance, and please feel free to educate me.
> 
> So I guess if we have something
> 
> struct zspage {
> 	..
> 	struct zpdesc *first_desc;
> 	..
> }
> 
> and we "chain" zpdesc-s to form a zspage, and make each of them point to
> a corresponding struct page (memdesc -> *page), then it'll resemble current
> zsmalloc and should work for everyone? I also assume for zspdesc-s zsmalloc
> will need to maintain a dedicated kmem_cache?

Yes, it would be a better way moving to memdesc, and using kmem_cache for zpdesc-s
seems workable.

Thanks
Alex