From c2f1a551dea8b37c2e0cb886885c250fb703e9d8 Mon Sep 17 00:00:00 2001 From: Meelap Shah Date: Tue, 17 Jul 2007 04:04:39 -0700 Subject: 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" Signed-off-by: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 1 + 1 file changed, 1 insertion(+) (limited to 'mm') 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 -- cgit v1.2.2