linux-kernel - Re: [PATCHv3 1/2] zsmalloc: introduce zs_huge

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Message-ID: <20180226055804.GD112402@rodete-desktop-imager.corp.google.com>
Date:   Mon, 26 Feb 2018 14:58:04 +0900
From:   Minchan Kim <minchan@...nel.org>
To:     Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Mike Rapoport <rppt@...ux.vnet.ibm.com>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>
Subject: Re: [PATCHv3 1/2] zsmalloc: introduce zs_huge_object() function

Hi Sergey,

On Mon, Feb 26, 2018 at 02:49:27PM +0900, Sergey Senozhatsky wrote:
> > I think it's simple enough. :)
> 
> Right. The changes are pretty trivial, that's why I kept then in
> 2 simple patches. Besides, I didn't want to mix zsmalloc and zram
> changes.

As I said earlier, it's not thing we usually do, at least, MM.
Anyway, I don't want to insist on it because it depends each
person's point of view what's the better for review, git-bisect.

> 
> > Can't zram ask to zsmalloc about what size is for hugeobject from?
> > With that, zram can save the wartermark in itself and use it.
> > What I mean is as follows,
> > 
> > zram:
> > 	size_t huge_size = _zs_huge_object(pool);
> > 	..
> > 	..
> > 	if (comp_size >= huge_size)
> > 		memcpy(dst, src, 4K);
> 
> Yes, can do. My plan was to keep it completely internally to zsmalloc.
> Who knows, it might become smart enough one day to do something more
> than just size comparison. Any reason you used that leading underscore

Let's do that in future if someone want it. :)

> in _zs_huge_object()?


Nope. It's just typo. Let's think better name.
How about using zs_huge_size()?