linux-kernel - Re: [PATCH] zsmalloc: Fix races between modifications of fullness and isolated

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Message-ID: <20230726025711.GI955071@google.com>
Date:   Wed, 26 Jul 2023 11:57:11 +0900
From:   Sergey Senozhatsky <senozhatsky@...omium.org>
To:     Andrew Yang <andrew.yang@...iatek.com>
Cc:     Minchan Kim <minchan@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        wsd_upstream@...iatek.com, casper.li@...iatek.com,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org,
        Sergey Senozhatsky <senozhatsky@...omium.org>
Subject: Re: [PATCH] zsmalloc: Fix races between modifications of fullness
 and isolated

On (23/07/26 11:31), Sergey Senozhatsky wrote:
> On (23/07/21 14:37), Andrew Yang wrote:
> > 
> > Since fullness and isolated share the same unsigned int,
> > modifications of them should be protected by the same lock.
> 
> Sorry, I don't think I follow. Can you please elaborate?
> What is fullness in this context?

Oh, my bad, so that's zspage's fullness:FULLNESS_BITS and
isolated:ISOLATED_BITS.  I somehow thought about something
very different (page isolated, not zspage isolated).