From: Dave Hansen <dave.hansen@intel.com>
To: Jan Kara <jack@suse.cz>
Cc: Andy Lutomirski <luto@amacapital.net>,
linux-mm@kvack.org, linux-ext4@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [RFC 0/3] Add madvise(..., MADV_WILLWRITE)
Date: Wed, 07 Aug 2013 10:40:52 -0700 [thread overview]
Message-ID: <520286A4.1020101@intel.com> (raw)
In-Reply-To: <20130807134058.GC12843@quack.suse.cz>
On 08/07/2013 06:40 AM, Jan Kara wrote:
> One question before I look at the patches: Why don't you use fallocate()
> in your application? The functionality you require seems to be pretty
> similar to it - writing to an already allocated block is usually quick.
One problem I've seen is that it still costs you a fault per-page to get
the PTEs in to a state where you can write to the memory. MADV_WILLNEED
will do readahead to get the page cache filled, but it still leaves the
pages unmapped. Those faults get expensive when you're trying to do a
couple hundred million of them all at once.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2013-08-07 17:40 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-05 19:43 [RFC 0/3] Add madvise(..., MADV_WILLWRITE) Andy Lutomirski
2013-08-05 19:43 ` [RFC 1/3] mm: Add MADV_WILLWRITE to indicate that a range will be written to Andy Lutomirski
2013-08-05 19:44 ` [RFC 2/3] fs: Add block_willwrite Andy Lutomirski
2013-08-05 19:44 ` [RFC 3/3] ext4: Implement willwrite for the delalloc case Andy Lutomirski
2013-08-07 13:40 ` [RFC 0/3] Add madvise(..., MADV_WILLWRITE) Jan Kara
2013-08-07 17:02 ` Andy Lutomirski
2013-08-07 17:40 ` Dave Hansen [this message]
2013-08-07 18:00 ` Andy Lutomirski
2013-08-08 10:18 ` Jan Kara
2013-08-08 15:56 ` Andy Lutomirski
2013-08-08 18:53 ` Jan Kara
2013-08-08 19:25 ` Andy Lutomirski
2013-08-08 22:58 ` Dave Hansen
2013-08-09 7:55 ` Jan Kara
2013-08-09 17:36 ` Andy Lutomirski
2013-08-09 20:34 ` Jan Kara
2013-08-09 17:42 ` Dave Hansen
2013-08-09 17:44 ` Andy Lutomirski
2013-08-12 22:44 ` Dave Hansen
2013-08-09 0:11 ` Andy Lutomirski
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=520286A4.1020101@intel.com \
--to=dave.hansen@intel.com \
--cc=jack@suse.cz \
--cc=linux-ext4@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@amacapital.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).