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| author | Meelap Shah <meelap@umich.edu> | 2007-07-17 04:04:39 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-17 10:23:07 -0700 |
| commit | c2f1a551dea8b37c2e0cb886885c250fb703e9d8 (patch) | |
| tree | 11a5f256703d856017ceb2268bd02b7b510dee30 /mm/page_alloc.c | |
| parent | 1e5140279f31e47d58ed6036ee61ba7a65710e63 (diff) | |
| download | lwn-c2f1a551dea8b37c2e0cb886885c250fb703e9d8.tar.gz lwn-c2f1a551dea8b37c2e0cb886885c250fb703e9d8.zip | |
knfsd: nfsd4: vary maximum delegation limit based on RAM size
Our original NFSv4 delegation policy was to give out a read delegation on any
open when it was possible to.
Since the lifetime of a delegation isn't limited to that of an open, a client
may quite reasonably hang on to a delegation as long as it has the inode
cached. This becomes an obvious problem the first time a client's inode cache
approaches the size of the server's total memory.
Our first quick solution was to add a hard-coded limit. This patch makes a
mild incremental improvement by varying that limit according to the server's
total memory size, allowing at most 4 delegations per megabyte of RAM.
My quick back-of-the-envelope calculation finds that in the worst case (where
every delegation is for a different inode), a delegation could take about
1.5K, which would make the worst case usage about 6% of memory. The new limit
works out to be about the same as the old on a 1-gig server.
[akpm@linux-foundation.org: Don't needlessly bloat vmlinux]
[akpm@linux-foundation.org: Make it right for highmem machines]
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_alloc.c')
| -rw-r--r-- | mm/page_alloc.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 1a889c3fec59..e2a10b957f23 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1484,6 +1484,7 @@ unsigned int nr_free_buffer_pages(void) { return nr_free_zone_pages(gfp_zone(GFP_USER)); } +EXPORT_SYMBOL_GPL(nr_free_buffer_pages); /* * Amount of free RAM allocatable within all zones |