| Date | Fri, 21 Nov 2008 00:17:04 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH 06/45] FS-Cache: Recruit a couple of page flags for cache management [ver #41] |
| |
On Thu, 20 Nov 2008 14:42:10 +0000 David Howells <dhowells@redhat.com> wrote:
> Recruit a couple of page flags to aid in cache management. The following extra > flags are defined: > > (1) PG_fscache (PG_private_2) > > The marked page is backed by a local cache and is pinning resources in the > cache driver. > > (2) PG_fscache_write (PG_owner_priv_2) > > The marked page is being written to the local cache. The page may not be > modified whilst this is in progress. > > If PG_fscache is set, then things that checked for PG_private will now also > check for that. This includes things like truncation and page invalidation. > The function page_has_private() had been added to make the checks for both > PG_private and PG_private_2 at the same time. > > ... > > index 74b9d90..da467b2 100644 > --- a/include/linux/page-flags.h > +++ b/include/linux/page-flags.h > @@ -79,9 +79,11 @@ enum pageflags { > PG_active, > PG_slab, > PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/ > + PG_owner_priv_2, /* Owner use. fs may use in pagecache */ > PG_arch_1, > PG_reserved, > PG_private, /* If pagecache, has fs-private data */ > + PG_private_2, /* If pagecache, has fs aux data */ > PG_writeback, /* Page is under writeback */
ow, that hurt. Every time someone does this I ask "how many are left" but nobody seems to know how to work it out.
How many are left?
> - if (PagePrivate(page) && > + if (page_has_private(page) &&
I'd suggest that we make PagePrivate() go away completely, to prevent accidental usages from sneaking back in. If that's practical.
|