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Date: Tue, 14 Aug 2018 09:51:55 +0900
From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Subject: Re: [PATCH] zsmalloc: fix linking bug in init_zspage
Message-ID: <20180814005155.GB20631@jagdpanzerIV>
References: <20180810002817.2667-1-zhouxianrong@tom.com>
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 <20180813105536.GA435@jagdpanzerIV>
 <20180814002416.GA34280@rodete-desktop-imager.corp.google.com>
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To: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>, zhouxianrong <zhouxianrong@tom.com>, linux-mm@kvack.org, linux-kernel@vger.kernel.org, ngupta@vflare.org, zhouxianrong <zhouxianrong@huawei.com>

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