linux-kernel - Re: [PATCH 2/5] fuse: Convert fuse_try_move

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Message-ID: <CAJfpegtRCngZtKpTuL47bvjrzisV2wPY5pwZkPJPqD=HGnW+vA@mail.gmail.com>
Date:   Mon, 14 Nov 2022 14:25:50 +0100
From:   Miklos Szeredi <miklos@...redi.hu>
To:     Vishal Moola <vishal.moola@...il.com>
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, akpm@...ux-foundation.org,
        Matthew Wilcox <willy@...radead.org>
Subject: Re: [PATCH 2/5] fuse: Convert fuse_try_move_page() to use folios

On Thu, 10 Nov 2022 at 19:36, Vishal Moola <vishal.moola@...il.com> wrote:
>
> On Tue, Nov 1, 2022 at 11:24 AM Matthew Wilcox <willy@...radead.org> wrote:
> >
> > On Tue, Nov 01, 2022 at 10:53:23AM -0700, Vishal Moola (Oracle) wrote:
> > > Converts the function to try to move folios instead of pages. Also
> > > converts fuse_check_page() to fuse_get_folio() since this is its only
> > > caller. This change removes 15 calls to compound_head().
> >
> > This all looks good.  I wonder if we should't add an assertion that the
> > page we're trying to steal is !large?  It seems to me that there are
> > assumptions in this part of fuse that it's only dealing with order-0
> > pages, and if someone gives it a page that's part of a large folio,
> > it's going to be messy.  Miklos, any thoughts?
>
> Miklos, could you please look over this patch?

I think this should take care of the large folio case in fuse_try_move_page():

    if (cs->len != PAGE_SIZE)
        goto out_fallback;

The patch looks okay.

Acked-by: Miklos Szeredi <mszeredi@...hat.com>

Thanks,
Miklos