From: Al Viro <viro@ZenIV.linux.org.uk>
To: Mike Marshall <hubcap@omnibond.com>
Cc: Christoph Hellwig <hch@lst.de>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Boaz Harrosh <ooo@electrozaur.com>,
Greg Kroah-Hartman <greg@kroah.com>
Subject: Re: [GIT PULL] Orangefs (text only resend)
Date: Tue, 8 Sep 2015 00:22:06 +0100 [thread overview]
Message-ID: <20150907232206.GL22011@ZenIV.linux.org.uk> (raw)
In-Reply-To: <CAOg9mSTbuo7Mtv8qqDs9Megm=sG6FnzDu=tSeZq8WLfEN4RZVg@mail.gmail.com>
On Mon, Sep 07, 2015 at 05:10:11PM -0400, Mike Marshall wrote:
> I have failed so far today to figure out what you mean by GrepTFS or GTFS...
grep the fucking source, of course...
> and https://lwn.net/lwn/kernel/LDD2/ch07.html... I don't yet see where we're
> doing GFP_KERNEL allocations within held locks... could you describe in more
> detail one of the ones you saw?
You don't want e.g. to have allocation request triggering an attempt to write
a dirty page on a shared mapping of a file from your fs while you are holding
a mutex that would block that attempt *and* waiting for a allocation to
succeed.
Same story as when a block driver needs to allocate something to process a
write request - we do _not_ want that to trigger writes.
That's what GFP_NOFS and GFP_NOIO are about; LDD2 is old and the analogue
back then used to be called GFP_BUFFER.
Which (if any) is needed depends on the locks you are holding; something like
->i_mutex on a directory is not a problem, but things like your request mutex
almost certainly *are*.
next prev parent reply other threads:[~2015-09-07 23:22 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-01 15:42 [GIT PULL] Orangefs (text only resend) Mike Marshall
2015-09-02 23:34 ` Linus Torvalds
2015-09-03 1:13 ` Mike Marshall
2015-09-03 1:28 ` Linus Torvalds
2015-09-03 20:22 ` Linus Torvalds
2015-09-03 22:18 ` Mike Marshall
2015-09-03 22:44 ` Greg Kroah-Hartman
2015-09-06 6:35 ` Christoph Hellwig
2015-09-06 9:08 ` Al Viro
2015-09-06 14:52 ` Mike Marshall
2015-09-06 15:00 ` Mike Marshall
2015-09-06 20:20 ` Al Viro
2015-09-07 6:37 ` Al Viro
2015-09-07 21:10 ` Mike Marshall
2015-09-07 23:22 ` Al Viro [this message]
2015-09-08 0:47 ` Theodore Ts'o
2015-09-08 2:49 ` Dave Chinner
2015-09-08 14:48 ` Christoph Hellwig
2015-09-08 18:21 ` Mike Marshall
2015-09-09 15:05 ` Mike Marshall
2015-09-11 21:12 ` Mike Marshall
2015-09-11 22:24 ` Al Viro
2015-09-13 11:56 ` Mike Marshall
2015-09-11 23:20 ` Linus Torvalds
2015-09-13 11:59 ` Mike Marshall
2015-09-06 14:35 ` Mike Marshall
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