From: David Howells <dhowells@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: dhowells@redhat.com, Josef Bacik <josef@toxicpanda.com>,
Matthew Wilcox <willy@infradead.org>, Chris Mason <clm@fb.com>,
David Sterba <dsterba@suse.com>,
Trond Myklebust <trondmy@hammerspace.com>,
Anna Schumaker <anna.schumaker@netapp.com>,
Steve French <sfrench@samba.org>,
Dominique Martinet <asmadeus@codewreck.org>,
Christoph Hellwig <hch@lst.de>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Linux-MM <linux-mm@kvack.org>,
linux-cachefs@redhat.com, linux-afs@lists.infradead.org,
"open list:NFS, SUNRPC, AND..." <linux-nfs@vger.kernel.org>,
CIFS <linux-cifs@vger.kernel.org>,
ceph-devel@vger.kernel.org, v9fs-developer@lists.sourceforge.net,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Jeff Layton <jlayton@redhat.com>,
David Wysochanski <dwysocha@redhat.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4 02/28] mm: Add an unlock function for PG_private_2/PG_fscache
Date: Wed, 17 Mar 2021 10:53:41 +0000 [thread overview]
Message-ID: <38368.1615978421@warthog.procyon.org.uk> (raw)
In-Reply-To: <31382.1615971849@warthog.procyon.org.uk>
David Howells <dhowells@redhat.com> wrote:
> (1) For the old fscache code that I'm trying to phase out, it does not take a
> ref when PG_fscache is taken (probably incorrectly), relying instead on
> releasepage, etc. getting called to strip the PG_fscache bit. PG_fscache
> is held for the lifetime of the page, indicating that fscache knows about
> it and might access it at any time (to write to the cache in the
> background for example or to move pages around in the cache).
>
> Here PG_fscache should not prevent page eviction or migration and it's
> analogous to PG_private.
>
> That said, the old fscache code keeps its own radix trees of pages that
> are undergoing write to the cache, so to allow a page to be evicted,
> releasepage and co. have to consult those
> (__fscache_maybe_release_page()).
Note that, ideally, we'll be able to remove the old fscache I/O code in the
next merge window or the one after.
David
next prev parent reply other threads:[~2021-03-17 10:54 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-10 16:54 [PATCH v4 00/28] Network fs helper library & fscache kiocb API David Howells
2021-03-10 16:54 ` [PATCH v4 01/28] iov_iter: Add ITER_XARRAY David Howells
2021-03-10 16:54 ` [PATCH v4 02/28] mm: Add an unlock function for PG_private_2/PG_fscache David Howells
2021-03-16 19:07 ` Matthew Wilcox
2021-03-17 0:43 ` Linus Torvalds
2021-03-17 2:12 ` Josef Bacik
2021-03-17 2:35 ` Linus Torvalds
2021-03-17 9:04 ` David Howells
2021-03-17 10:53 ` David Howells [this message]
2021-03-16 20:38 ` David Howells
2021-03-16 23:32 ` Matthew Wilcox
2021-03-21 10:53 ` Matthew Wilcox
2021-03-22 10:56 ` David Howells
2021-03-23 13:17 ` David Howells
2021-03-23 13:51 ` Matthew Wilcox
2021-03-23 14:16 ` David Howells
2021-03-23 22:06 ` David Howells
2021-03-10 16:55 ` [PATCH v4 03/28] mm: Implement readahead_control pageset expansion David Howells
2021-03-10 16:55 ` [PATCH v4 04/28] netfs: Make a netfs helper module David Howells
2021-03-10 16:55 ` [PATCH v4 05/28] netfs: Documentation for helper library David Howells
2021-03-10 16:55 ` [PATCH v4 06/28] netfs, mm: Move PG_fscache helper funcs to linux/netfs.h David Howells
2021-03-10 16:56 ` [PATCH v4 07/28] netfs, mm: Add unlock_page_fscache() and wait_on_page_fscache() David Howells
2021-03-10 16:56 ` [PATCH v4 08/28] netfs: Provide readahead and readpage netfs helpers David Howells
2021-03-21 1:42 ` Matthew Wilcox
2021-03-22 17:13 ` David Howells
2021-03-10 16:56 ` [PATCH v4 09/28] netfs: Add tracepoints David Howells
2021-03-10 16:56 ` [PATCH v4 10/28] netfs: Gather stats David Howells
2021-03-10 16:56 ` [PATCH v4 11/28] netfs: Add write_begin helper David Howells
2021-03-10 16:57 ` [PATCH v4 12/28] netfs: Define an interface to talk to a cache David Howells
2021-03-10 16:57 ` [PATCH v4 13/28] netfs: Hold a ref on a page when PG_private_2 is set David Howells
2021-03-10 16:57 ` [PATCH v4 14/28] fscache, cachefiles: Add alternate API to use kiocb for read/write to cache David Howells
2021-03-10 16:57 ` [PATCH v4 15/28] afs: Disable use of the fscache I/O routines David Howells
2021-03-10 16:58 ` [PATCH v4 16/28] afs: Pass page into dirty region helpers to provide THP size David Howells
2021-03-10 16:58 ` [PATCH v4 17/28] afs: Print the operation debug_id when logging an unexpected data version David Howells
2021-03-10 16:58 ` [PATCH v4 18/28] afs: Move key to afs_read struct David Howells
2021-03-10 16:58 ` [PATCH v4 19/28] afs: Don't truncate iter during data fetch David Howells
2021-03-10 16:58 ` [PATCH v4 20/28] afs: Log remote unmarshalling errors David Howells
2021-03-10 16:59 ` [PATCH v4 21/28] afs: Set up the iov_iter before calling afs_extract_data() David Howells
2021-03-10 16:59 ` [PATCH v4 22/28] afs: Use ITER_XARRAY for writing David Howells
2021-03-10 16:59 ` [PATCH v4 23/28] afs: Wait on PG_fscache before modifying/releasing a page David Howells
2021-03-10 16:59 ` [PATCH v4 24/28] afs: Extract writeback extension into its own function David Howells
2021-03-10 16:59 ` [PATCH v4 25/28] afs: Prepare for use of THPs David Howells
2021-03-10 17:00 ` [PATCH v4 26/28] afs: Use the fs operation ops to handle FetchData completion David Howells
2021-03-10 17:00 ` [PATCH v4 27/28] afs: Use new fscache read helper API David Howells
2021-03-10 17:00 ` [PATCH v4 28/28] afs: Use the fscache_write_begin() helper David Howells
2021-03-16 11:34 ` [PATCH v4 08/28] netfs: Provide readahead and readpage netfs helpers David Howells
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