linux-kernel - Re: [PATCH] zsmalloc: fix linking bug in init

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Date:   Tue, 14 Aug 2018 09:51:55 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
To:     Minchan Kim <minchan@...nel.org>
Cc:     Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
        zhouxianrong <zhouxianrong@....com>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, ngupta@...are.org,
        zhouxianrong <zhouxianrong@...wei.com>
Subject: Re: [PATCH] zsmalloc: fix linking bug in init_zspage

Hi Minchan,

On (08/14/18 09:24), Minchan Kim wrote:
> > Any thoughts?
>
> If we want a refactoring, I'm not against but description said it tiggered
> BUG_ON on zs_map_object rarely. That means it should be stable material
> and need more description to understand. Please be more specific with
> some example.

I don't have any BUG_ON on hands. Would be great if zhouxianrong could
post some backtraces or more info/explanation.

> The reason I'm hesitating is zsmalloc moves ZS_FULL group
> when the zspage->inuse is equal to class->objs_per_zspage so I thought
> it shouldn't allocate last partial object.

Maybe, allocating last partial object does look a bit hacky - it's not a
valid object anyway, but I'm not suggesting that we need to change it.
Let's hear from zhouxianrong.

	-ss