From: Nick Piggin <nickpiggin@yahoo.com.au>
To: David Howells <dhowells@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, nfsv4@linux-nfs.org,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 21/41] CacheFiles: Permit the page lock state to be monitored [ver #48]
Date: Sat, 4 Apr 2009 17:09:31 +1100 [thread overview]
Message-ID: <200904041709.31651.nickpiggin@yahoo.com.au> (raw)
In-Reply-To: <20090403155624.28714.87176.stgit@warthog.procyon.org.uk>
On Saturday 04 April 2009 02:56:24 David Howells wrote:
> Add a function to install a monitor on the page lock waitqueue for a particular
> page, thus allowing the page being unlocked to be detected.
>
> This is used by CacheFiles to detect read completion on a page in the backing
> filesystem so that it can then copy the data to the waiting netfs page.
This is the only thing I'm still worried about in core code. The extra
page flag (which is probably unusable for any other fs, due to its
semantics) is an issue, but Andrew seemed like he was willing to spend
*2* page flags on this, so I'm sure he's happy with 1.
But this I still don't like.
I didn't get any reply when asking about the asynchronous nature of
this. It certainly adds huge complexity to the code, at points which
can tend to be quite synchronous anyway.
I would really like to know exactly why it *has* to be asynchronous,
and see what the diff looks like between a simple synchronous design
and what you have here.
next prev parent reply other threads:[~2009-04-04 6:09 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-03 15:54 [PATCH 00/41] Permit filesystem local caching " David Howells
2009-04-03 15:54 ` [PATCH 01/41] Create a dynamically sized pool of threads for doing very slow work items " David Howells
2009-04-03 15:54 ` [PATCH 02/41] Make slow-work thread pool actually dynamic " David Howells
2009-04-03 15:54 ` [PATCH 03/41] Make the slow work pool configurable " David Howells
2009-04-03 15:54 ` [PATCH 04/41] Document the slow work thread pool " David Howells
2009-04-03 15:55 ` [PATCH 05/41] FS-Cache: Release page->private after failed readahead " David Howells
2009-04-04 6:00 ` Nick Piggin
2009-04-03 15:55 ` [PATCH 06/41] FS-Cache: Recruit a page flags for cache management " David Howells
2009-04-04 6:04 ` Nick Piggin
2009-04-03 15:55 ` [PATCH 07/41] FS-Cache: Add the FS-Cache netfs API and documentation " David Howells
2009-04-03 15:55 ` [PATCH 08/41] FS-Cache: Add the FS-Cache cache backend " David Howells
2009-04-03 15:55 ` [PATCH 09/41] FS-Cache: Add main configuration option, module entry points and debugging " David Howells
2009-04-03 15:55 ` [PATCH 10/41] FS-Cache: Add use of /proc and presentation of statistics " David Howells
2009-04-04 17:39 ` Christoph Hellwig
2009-04-03 15:55 ` [PATCH 11/41] FS-Cache: Root index definition " David Howells
2009-04-03 15:55 ` [PATCH 12/41] FS-Cache: Add cache tag handling " David Howells
2009-04-03 15:55 ` [PATCH 13/41] FS-Cache: Add cache management " David Howells
2009-04-03 15:55 ` [PATCH 14/41] FS-Cache: Provide a slab for cookie allocation " David Howells
2009-04-03 15:55 ` [PATCH 15/41] FS-Cache: Add netfs registration " David Howells
2009-04-03 15:55 ` [PATCH 16/41] FS-Cache: Bit waiting helpers " David Howells
2009-04-03 15:56 ` [PATCH 17/41] FS-Cache: Object management state machine " David Howells
2009-04-03 15:56 ` [PATCH 18/41] FS-Cache: Implement the cookie management part of the netfs API " David Howells
2009-04-03 15:56 ` [PATCH 19/41] FS-Cache: Add and document asynchronous operation handling " David Howells
2009-04-03 15:56 ` [PATCH 20/41] FS-Cache: Implement data I/O part of netfs API " David Howells
2009-04-03 15:56 ` [PATCH 21/41] CacheFiles: Permit the page lock state to be monitored " David Howells
2009-04-04 6:09 ` Nick Piggin [this message]
2009-04-04 14:22 ` Nick Piggin
2009-04-04 22:13 ` David Howells
2009-04-06 8:31 ` Nick Piggin
2009-04-04 11:31 ` David Howells
2009-04-06 9:34 ` Nick Piggin
2009-04-03 15:56 ` [PATCH 22/41] CacheFiles: Export things for CacheFiles " David Howells
2009-04-03 15:56 ` [PATCH 23/41] CacheFiles: A cache that backs onto a mounted filesystem " David Howells
2009-04-03 15:56 ` [PATCH 24/41] FS-Cache: Make kAFS use FS-Cache " David Howells
2009-04-03 15:56 ` [PATCH 25/41] NFS: Add comment banners to some NFS functions " David Howells
2009-04-03 15:56 ` [PATCH 26/41] NFS: Add FS-Cache option bit and debug bit " David Howells
2009-04-03 15:56 ` [PATCH 27/41] NFS: Permit local filesystem caching to be enabled for NFS " David Howells
2009-04-03 15:57 ` [PATCH 28/41] NFS: Register NFS for caching and retrieve the top-level index " David Howells
2009-04-03 15:57 ` [PATCH 29/41] NFS: Define and create server-level objects " David Howells
2009-04-03 15:57 ` [PATCH 30/41] NFS: Define and create superblock-level " David Howells
2009-04-03 15:57 ` [PATCH 31/41] NFS: Define and create inode-level cache " David Howells
2009-04-03 15:57 ` [PATCH 32/41] NFS: Use local disk inode cache " David Howells
2009-04-03 15:57 ` [PATCH 33/41] NFS: Invalidate FsCache page flags when cache removed " David Howells
2009-04-03 15:57 ` [PATCH 34/41] NFS: Add some new I/O counters for FS-Cache doing things for NFS " David Howells
2009-04-03 15:57 ` [PATCH 35/41] NFS: FS-Cache page management " David Howells
2009-04-03 15:57 ` [PATCH 36/41] NFS: Add read context retention for FS-Cache to call back with " David Howells
2009-04-03 15:57 ` [PATCH 37/41] NFS: nfs_readpage_async() needs to be accessible as a fallback for local caching " David Howells
2009-04-03 15:57 ` [PATCH 38/41] NFS: Read pages from FS-Cache into an NFS inode " David Howells
2009-04-03 15:57 ` [PATCH 39/41] NFS: Store pages from an NFS inode into a local cache " David Howells
2009-04-03 15:58 ` [PATCH 40/41] NFS: Display local caching state " David Howells
2009-04-03 15:58 ` [PATCH 41/41] NFS: Add mount options to enable local caching on NFS " David Howells
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