linux-kernel - Re: [PATCH v5 10/18] zsmalloc: factor out pool locking helpers

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Message-ID: <28ed23c00effdd531a9e027feb0bc08e22fc677d@linux.dev>
Date: Thu, 13 Feb 2025 01:12:51 +0000
From: "Yosry Ahmed" <yosry.ahmed@...ux.dev>
To: "Sergey Senozhatsky" <senozhatsky@...omium.org>
Cc: "Sergey Senozhatsky" <senozhatsky@...omium.org>, "Andrew Morton"
 <akpm@...ux-foundation.org>, "Kairui Song" <ryncsn@...il.com>, "Minchan
 Kim" <minchan@...nel.org>, linux-mm@...ck.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 10/18] zsmalloc: factor out pool locking helpers

February 12, 2025 at 4:57 PM, "Sergey Senozhatsky" <senozhatsky@...omium.org> wrote:



> 
> On (25/02/12 16:18), Yosry Ahmed wrote:
> 
> > 
> > On Wed, Feb 12, 2025 at 03:27:08PM +0900, Sergey Senozhatsky wrote:
> > 
> >  We currently have a mix of migrate_{read,write}_lock() helpers
> > 
> >  that lock zspages, but it's zs_pool that actually has a ->migrate_lock
> > 
> >  access to which is opene-coded. Factor out pool migrate locking
> > 
> >  into helpers, zspage migration locking API will be renamed to
> > 
> >  reduce confusion.
> > 
> >  
> > 
> >  It's worth mentioning that zsmalloc locks sync not only migration,
> > 
> >  but also compaction.
> > 
> >  
> > 
> >  Signed-off-by: Sergey Senozhatsky <senozhatsky@...omium.org>
> > 
> >  
> > 
> >  FWIW I don't see a lot of value in the helpers (renaming the lock is
> > 
> >  useful tho).
> > 
> 
> I want to hide the details, keep them in one place and at some
> 
> point *in the future* have the same "locking rules" as for zspage
> 
> lock. Also *possibly* throwing a couple of lockdep assertions.
> 
> So I'd prefer to abstract all of these.


I'd prefer to introduce the abstractions when they are needed tbh. Right now they just make the code less readable.