From: David Howells <dhowells@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: dhowells@redhat.com, Matthew Wilcox <willy@infradead.org>,
Jeff Layton <jlayton@redhat.com>,
David Wysochanski <dwysocha@redhat.com>,
Anna Schumaker <anna.schumaker@netapp.com>,
Trond Myklebust <trondmy@hammerspace.com>,
Steve French <sfrench@samba.org>,
Dominique Martinet <asmadeus@codewreck.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
ceph-devel@vger.kernel.org, linux-afs@lists.infradead.org,
linux-cachefs@redhat.com, CIFS <linux-cifs@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
"open list:NFS, SUNRPC, AND..." <linux-nfs@vger.kernel.org>,
v9fs-developer@lists.sourceforge.net,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [GIT PULL] fscache: I/O API modernisation and netfs helper library
Date: Tue, 09 Feb 2021 21:10:42 +0000 [thread overview]
Message-ID: <617685.1612905042@warthog.procyon.org.uk> (raw)
In-Reply-To: <CAHk-=wj-k86FOqAVQ4ScnBkX3YEKuMzqTEB2vixdHgovJpHc9w@mail.gmail.com>
Linus Torvalds <torvalds@linux-foundation.org> wrote:
> The PG_fscache bit waiting functions are completely crazy. The comment
> about "this will wake up others" is actively wrong,
You mean this?
/**
* unlock_page_fscache - Unlock a page pinned with PG_fscache
* @page: The page
*
* Unlocks the page and wakes up sleepers in wait_on_page_fscache(). Also
* wakes those waiting for the lock and writeback bits because the wakeup
* mechanism is shared. But that's OK - those sleepers will just go back to
* sleep.
*/
Actually, you're right. The wakeup check func is evaluated by the
waker-upper. I can fix the comment with a patch.
> and the waiting function looks insane, because you're mixing the two names
> for "fscache" which makes the code look totally incomprehensible. Why would
> we wait for PF_fscache, when PG_private_2 was set? Yes, I know why, but the
> code looks entirely nonsensical.
IIRC someone insisted that I should make it a generic name and put the
accessor functions in the fscache headers (which means they aren't available
to core code), but I don't remember who (maybe Andrew? it was before mid-2007)
- kind of like PG_checked is an alias for PG_owner_priv_1.
I'd be quite happy to move the accessors for PG_fscache to the
linux/page-flags.h as that would simplify things.
David
next prev parent reply other threads:[~2021-02-09 22:50 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-09 16:09 [GIT PULL] fscache: I/O API modernisation and netfs helper library David Howells
2021-02-09 19:06 ` Linus Torvalds
2021-02-09 19:45 ` Jeff Layton
2021-02-09 20:21 ` Matthew Wilcox
2021-02-09 21:19 ` Linus Torvalds
2021-02-09 21:55 ` David Howells
2021-02-10 16:36 ` David Howells
2021-02-09 21:25 ` David Howells
2021-02-09 22:42 ` David Wysochanski
2021-02-09 21:10 ` David Howells [this message]
2021-02-10 16:29 ` David Howells
2021-02-10 16:33 ` David Howells
2021-02-10 20:43 ` Linus Torvalds
2021-02-11 22:38 ` David Howells
2021-02-11 23:20 ` David Howells
2021-02-12 16:40 ` David Wysochanski
2021-02-13 1:05 ` Linus Torvalds
2021-02-15 0:22 ` David Howells
2021-02-15 1:01 ` Linus Torvalds
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