From: Christoph Hellwig <hch@lst.de>
To: Ingo Molnar <mingo@kernel.org>
Cc: Boaz Harrosh <boaz@plexistor.com>, Christoph Hellwig <hch@lst.de>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org,
Ross Zwisler <ross.zwisler@linux.intel.com>,
Dan Williams <dan.j.williams@intel.com>,
Matthew Wilcox <matthew.r.wilcox@intel.com>
Subject: Re: [GIT PULL] PMEM driver for v4.1
Date: Mon, 13 Apr 2015 19:22:25 +0200 [thread overview]
Message-ID: <20150413172225.GC14243@lst.de> (raw)
In-Reply-To: <20150413123535.GA2666@gmail.com>
On Mon, Apr 13, 2015 at 02:35:35PM +0200, Ingo Molnar wrote:
> How does splice work with DAX files?
By falling back to default_file_splice_read/default_file_splice_write
which doesn't use the iter ops, but instead requires a copy in the
splice code. But given that the actual underlying reads and writes
bypass the pagecache it's not any less effiecient than the normal
pagecache based splice.
> AFAICS vmsplice() won't work, as
> it uses get_user_pages(), which needs struct page backing.
Exactly.
> Also, how
> will f_op->sendpage() work? That too needs page backing.
default_file_splice_read allocates it's own kernel pages, which are
then passed to ->sendpage.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Ingo Molnar <mingo@kernel.org>
Cc: Boaz Harrosh <boaz@plexistor.com>, Christoph Hellwig <hch@lst.de>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-nvdimm@ml01.01.org,
Ross Zwisler <ross.zwisler@linux.intel.com>,
Dan Williams <dan.j.williams@intel.com>,
Matthew Wilcox <matthew.r.wilcox@intel.com>
Subject: Re: [GIT PULL] PMEM driver for v4.1
Date: Mon, 13 Apr 2015 19:22:25 +0200 [thread overview]
Message-ID: <20150413172225.GC14243@lst.de> (raw)
In-Reply-To: <20150413123535.GA2666@gmail.com>
On Mon, Apr 13, 2015 at 02:35:35PM +0200, Ingo Molnar wrote:
> How does splice work with DAX files?
By falling back to default_file_splice_read/default_file_splice_write
which doesn't use the iter ops, but instead requires a copy in the
splice code. But given that the actual underlying reads and writes
bypass the pagecache it's not any less effiecient than the normal
pagecache based splice.
> AFAICS vmsplice() won't work, as
> it uses get_user_pages(), which needs struct page backing.
Exactly.
> Also, how
> will f_op->sendpage() work? That too needs page backing.
default_file_splice_read allocates it's own kernel pages, which are
then passed to ->sendpage.
next prev parent reply other threads:[~2015-04-13 17:22 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-13 9:33 [GIT PULL] PMEM driver for v4.1 Ingo Molnar
2015-04-13 9:33 ` Ingo Molnar
2015-04-13 9:35 ` Christoph Hellwig
2015-04-13 9:35 ` Christoph Hellwig
2015-04-13 10:45 ` Ingo Molnar
2015-04-13 10:45 ` Ingo Molnar
2015-04-13 11:11 ` [Linux-nvdimm] " Yigal Korman
2015-04-13 11:11 ` Yigal Korman
2015-04-13 17:19 ` Christoph Hellwig
2015-04-13 17:19 ` Christoph Hellwig
2015-04-14 6:41 ` Boaz Harrosh
2015-04-14 6:41 ` Boaz Harrosh
2015-04-13 12:21 ` Boaz Harrosh
2015-04-13 12:21 ` Boaz Harrosh
2015-04-13 12:35 ` Ingo Molnar
2015-04-13 12:35 ` Ingo Molnar
2015-04-13 13:36 ` Boaz Harrosh
2015-04-13 13:36 ` Boaz Harrosh
2015-04-13 17:22 ` Christoph Hellwig [this message]
2015-04-13 17:22 ` Christoph Hellwig
2015-04-13 17:18 ` Christoph Hellwig
2015-04-13 17:18 ` Christoph Hellwig
2015-04-14 12:41 ` Ingo Molnar
2015-04-14 12:41 ` Ingo Molnar
2015-04-14 13:45 ` Boaz Harrosh
2015-04-14 13:45 ` Boaz Harrosh
2015-04-14 14:08 ` [Linux-nvdimm] " Elliott, Robert (Server Storage)
2015-04-14 14:08 ` Elliott, Robert (Server Storage)
2015-04-14 16:34 ` Dan Williams
2015-04-14 16:34 ` Dan Williams
2015-04-14 21:46 ` Elliott, Robert (Server Storage)
2015-04-14 21:46 ` Elliott, Robert (Server Storage)
2015-04-15 8:03 ` Ingo Molnar
2015-04-15 8:03 ` Ingo Molnar
2015-04-14 16:04 ` Dan Williams
2015-04-14 16:04 ` Dan Williams
2015-04-15 8:45 ` Ingo Molnar
2015-04-15 8:45 ` Ingo Molnar
2015-04-16 4:31 ` Dan Williams
2015-04-16 4:31 ` Dan Williams
2015-04-17 6:38 ` Christoph Hellwig
2015-04-17 6:38 ` Christoph Hellwig
2015-04-18 15:42 ` Linus Torvalds
2015-04-18 15:42 ` Linus Torvalds
2015-05-25 18:16 ` [Linux-nvdimm] " Matthew Wilcox
2015-05-25 18:16 ` Matthew Wilcox
2015-05-25 18:30 ` Ingo Molnar
2015-05-25 18:30 ` Ingo Molnar
2015-05-26 8:41 ` Boaz Harrosh
2015-05-26 8:41 ` Boaz Harrosh
2015-05-26 19:31 ` Matthew Wilcox
2015-05-26 19:31 ` Matthew Wilcox
2015-05-27 8:10 ` Boaz Harrosh
2015-05-27 8:10 ` Boaz Harrosh
2015-05-27 8:11 ` Christoph Hellwig
2015-05-27 8:11 ` Christoph Hellwig
2015-05-27 8:26 ` Boaz Harrosh
2015-05-27 8:26 ` Boaz Harrosh
2015-05-27 7:50 ` Ingo Molnar
2015-05-27 7:50 ` Ingo Molnar
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