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From: Matthew Wilcox <willy@infradead.org>
To: Amit Golander <amit@plexistor.com>
Cc: Miklos Szeredi <mszeredi@redhat.com>,
	Amir Goldstein <amir73il@gmail.com>,
	Amit Golander <Amit.Golander@netapp.com>,
	Andy Rudof <andy.rudoff@intel.com>,
	Anna Schumaker <Anna.Schumaker@netapp.com>,
	Boaz Harrosh <boazh@netapp.com>, Jan Kara <jack@suse.cz>,
	Jefff moyer <jmoyer@redhat.com>,
	Ric Wheeler <rwheeler@redhat.com>, Sage Weil <sweil@redhat.com>,
	Sagi Manole <sagim@netapp.com>,
	Shachar Sharon <Shachar.Sharon@netapp.com>,
	Steve French <smfrench@gmail.com>,
	Steven Whitehouse <swhiteho@redhat.com>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [RFC 1/7] mm: Add new vma flag VM_LOCAL_CPU
Date: Wed, 14 Mar 2018 09:48:25 -0700	[thread overview]
Message-ID: <20180314164825.GI29631@bombadil.infradead.org> (raw)
In-Reply-To: <CAON-v2ygEDCn90C9t-zadjsd5GRgj0ECqntQSDDtO_Zjk=KoVw@mail.gmail.com>

On Wed, Mar 14, 2018 at 04:27:20PM +0000, Amit Golander wrote:
> ZUFS is not intended or designed to replace FUSE. Just like RDMA is not
> intended to replace TCP.

Your intent is to have two independent approaches to permitting
filesystems-in-userspace to exist.  And I've pointed out that your
approach doesn't work for my use-case (and neither does FUSE).  While we
might accept two implementations of something, at the point that three
implementations are proposed, we usually say "No, come up with a better
solution that works for everybody".

> On Wed, 14 Mar 2018 at 8:39 Miklos Szeredi <mszeredi@redhat.com> wrote:
> 
> > On Wed, Mar 14, 2018 at 3:57 PM, Matthew Wilcox <willy@infradead.org>
> > wrote:
> > > On Wed, Mar 14, 2018 at 03:49:35PM +0100, Miklos Szeredi wrote:
> > >> On Wed, Mar 14, 2018 at 12:45 PM, Matthew Wilcox <willy@infradead.org>
> > wrote:
> > >> > Erm ... there's nothing wrong with having one pipe per CPU.  But pipes
> > >> > being non-seekable means that ZUFS can only handle synchronous I/Os.
> > >> > If you want to have a network backend, then you'd only be able to have
> > >> > one outstanding network request per pipe, which is really going to
> > suck
> > >> > for bandwidth.
> > >>
> > >> I guess ZUFS is mostly about fast synchronous access (please correct
> > >> me if I'm wrong).  Not sure that model fits network filesystems, where
> > >> performance of caching will dominate real life performance.
> > >
> > > I'm sure that's Boaz's use case ;-)  But if we're introducing
> > > a replacement for FUSE, let's make it better than FUSE, not just
> > > specialised to Boaz's use case.
> >
> > Okay, so the FUSE vs. ZUFS question was bound to be raised at some
> > point.  What's the high level thinking on this?
> >
> > We can make ZUFS be a better FUSE, but with a new API?  New API means
> > we'll lose existing user base.   Having a new API but adding a compat
> > layer may be able to work around that, but it's probably hard to fully
> > emulate the old API.
> >
> > What are the limiting factors in the FUSE API that are preventing
> > fixing these performance problems in FUSE?
> >
> > Or it's just that FUSE kernel implementation is a horrid piece of
> > bloat (true) and we need to do something from scratch without worrying
> > about backward compat issues?
> >
> > Is ZUFS planning to acquire a caching layer?
> >
> > Btw, what is happening when a ZUFS file is mmaped?
> >
> > Thanks,
> > Miklos
> >

  parent reply	other threads:[~2018-03-14 16:48 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-13 17:14 [RFC 0/7] first draft of ZUFS - the Kernel part Boaz Harrosh
2018-03-13 17:15 ` [RFC 1/7] mm: Add new vma flag VM_LOCAL_CPU Boaz Harrosh
2018-03-13 18:56   ` Matthew Wilcox
2018-03-14  8:20     ` Miklos Szeredi
2018-03-14 11:17       ` Matthew Wilcox
2018-03-14 11:31         ` Miklos Szeredi
2018-03-14 11:45           ` Matthew Wilcox
2018-03-14 14:49             ` Miklos Szeredi
2018-03-14 14:57               ` Matthew Wilcox
2018-03-14 15:39                 ` Miklos Szeredi
     [not found]                   ` <CAON-v2ygEDCn90C9t-zadjsd5GRgj0ECqntQSDDtO_Zjk=KoVw@mail.gmail.com>
2018-03-14 16:48                     ` Matthew Wilcox [this message]
2018-03-14 21:41       ` Boaz Harrosh
2018-03-15  8:47         ` Miklos Szeredi
2018-03-15 15:27           ` Boaz Harrosh
2018-03-15 15:34             ` Matthew Wilcox
2018-03-15 15:58               ` Boaz Harrosh
2018-03-15 16:10             ` Miklos Szeredi
2018-03-15 16:30               ` Boaz Harrosh
2018-03-15 20:42                 ` Miklos Szeredi
2018-04-25 12:21                   ` Boaz Harrosh
2018-05-07 10:46                     ` Miklos Szeredi
2018-03-13 17:17 ` [RFC 2/7] fs: Add the ZUF filesystem to the build + License Boaz Harrosh
2018-03-13 20:16   ` Andreas Dilger
2018-03-14 17:21     ` Boaz Harrosh
2018-03-15  4:21       ` Andreas Dilger
2018-03-15 13:58         ` Boaz Harrosh
2018-03-13 17:18 ` [RFC 3/7] zuf: Preliminary Documentation Boaz Harrosh
2018-03-13 20:32   ` Randy Dunlap
2018-03-14 18:01     ` Boaz Harrosh
2018-03-14 19:16       ` Randy Dunlap
2018-03-13 17:22 ` [RFC 4/7] zuf: zuf-rootfs && zuf-core Boaz Harrosh
2018-03-13 17:36   ` Boaz Harrosh
2018-03-14 12:56     ` Nikolay Borisov
2018-03-14 18:34       ` Boaz Harrosh
2018-03-13 17:25 ` [RFC 5/7] zus: Devices && mounting Boaz Harrosh
2018-03-13 17:38   ` Boaz Harrosh
2018-03-13 17:28 ` [RFC 6/7] zuf: Filesystem operations Boaz Harrosh
2018-03-13 17:39   ` Boaz Harrosh
2018-03-13 17:32 ` [RFC 7/7] zuf: Write/Read && mmap implementation Boaz Harrosh

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