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References: <20211220085649.8196-1-songmuchun@bytedance.com>
 <20211220085649.8196-4-songmuchun@bytedance.com> <Yd3SoypOW0EBZj6K@carbon.dhcp.thefacebook.com>
In-Reply-To: <Yd3SoypOW0EBZj6K@carbon.dhcp.thefacebook.com>
From:   Muchun Song <songmuchun@bytedance.com>
Date:   Wed, 12 Jan 2022 10:54:32 +0800
Message-ID: <CAMZfGtU7qw4C3SaF=D5NYpn5oyo4mc5o=Y8TCOkG5a58W5DYRA@mail.gmail.com>
Subject: Re: [PATCH v5 03/16] fs: introduce alloc_inode_sb() to allocate
 filesystems specific inode
To:     Roman Gushchin <guro@fb.com>
Cc:     Matthew Wilcox <willy@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        Shakeel Butt <shakeelb@google.com>,
        Yang Shi <shy828301@gmail.com>, Alex Shi <alexs@kernel.org>,
        Wei Yang <richard.weiyang@gmail.com>,
        Dave Chinner <david@fromorbit.com>,
        trond.myklebust@hammerspace.com, anna.schumaker@netapp.com,
        jaegeuk@kernel.org, chao@kernel.org,
        Kari Argillander <kari.argillander@gmail.com>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux Memory Management List <linux-mm@kvack.org>,
        linux-nfs@vger.kernel.org, Qi Zheng <zhengqi.arch@bytedance.com>,
        Xiongchun duan <duanxiongchun@bytedance.com>,
        Fam Zheng <fam.zheng@bytedance.com>,
        Muchun Song <smuchun@gmail.com>
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On Wed, Jan 12, 2022 at 2:55 AM Roman Gushchin <guro@fb.com> wrote:
>
> On Mon, Dec 20, 2021 at 04:56:36PM +0800, Muchun Song wrote:
> > The allocated inode cache is supposed to be added to its memcg list_lru
> > which should be allocated as well in advance. That can be done by
> > kmem_cache_alloc_lru() which allocates object and list_lru. The file
> > systems is main user of it. So introduce alloc_inode_sb() to allocate
> > file system specific inodes and set up the inode reclaim context
> > properly. The file system is supposed to use alloc_inode_sb() to
> > allocate inodes. In the later patches, we will convert all users to the
> > new API.
> >
> > Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> > ---
> >  Documentation/filesystems/porting.rst |  5 +++++
> >  fs/inode.c                            |  2 +-
> >  include/linux/fs.h                    | 11 +++++++++++
> >  3 files changed, 17 insertions(+), 1 deletion(-)
> >
> > diff --git a/Documentation/filesystems/porting.rst b/Documentation/filesystems/porting.rst
> > index bf19fd6b86e7..c9c157d7b7bb 100644
> > --- a/Documentation/filesystems/porting.rst
> > +++ b/Documentation/filesystems/porting.rst
> > @@ -45,6 +45,11 @@ typically between calling iget_locked() and unlocking the inode.
> >
> >  At some point that will become mandatory.
> >
> > +**mandatory**
> > +
> > +The foo_inode_info should always be allocated through alloc_inode_sb() rather
> > +than kmem_cache_alloc() or kmalloc() related.
>
> I'd add a couple of words on why it has to be allocated this way.

Will do.

> > +
> >  ---
>
> Reviewed-by: Roman Gushchin <guro@fb.com>

Thanks.