lkml.org 
[lkml]   [2007]   [Jun]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH 007 of 8] knfsd: nfsd4: vary maximum delegation limit based on RAM size
On Wed, 27 Jun 2007 22:15:52 -0400 "J. Bruce Fields" <bfields@fieldses.org> wrote:

> + /*
> + * Allow at most 4 delegations per megabyte of RAM. Quick
> + * estimates suggest that in the worst case (where every delegation
> + * is for a different inode), a delegation could take about 1.5K,
> + * giving a worst case usage of about 6% of memory.
> + */
> sys.totalram >>= (18 - PAGE_SHIFT);

6% of 32GB is 2GB is too much for a large highmem machine. We should base
this on the amount of kernel-addressable memory (aka lowmem).

How's this?

static void
set_max_delegations(void)
{
/*
* Allow at most 4 delegations per megabyte of RAM. Quick
* estimates suggest that in the worst case (where every delegation
* is for a different inode), a delegation could take about 1.5K,
* giving a worst case usage of about 6% of memory.
*/
max_delegations = nr_free_buffer_pages() >> (20 - 2 - PAGE_SHIFT);
}


fs/nfsd/nfs4state.c | 7 ++-----
mm/page_alloc.c | 1 +

diff -puN fs/nfsd/nfs4state.c~knfsd-nfsd4-vary-maximum-delegation-limit-based-on-ram-size-fix-fix-fix-fix fs/nfsd/nfs4state.c
--- a/fs/nfsd/nfs4state.c~knfsd-nfsd4-vary-maximum-delegation-limit-based-on-ram-size-fix-fix-fix-fix
+++ a/fs/nfsd/nfs4state.c
@@ -49,6 +49,7 @@
#include <linux/nfsd/state.h>
#include <linux/nfsd/xdr4.h>
#include <linux/namei.h>
+#include <linux/swap.h>
#include <linux/mutex.h>
#include <linux/lockd/bind.h>
#include <linux/module.h>
@@ -3210,17 +3211,13 @@ get_nfs4_grace_period(void)
static void
set_max_delegations(void)
{
- struct sysinfo sys;
-
- si_meminfo(&sys);
/*
* Allow at most 4 delegations per megabyte of RAM. Quick
* estimates suggest that in the worst case (where every delegation
* is for a different inode), a delegation could take about 1.5K,
* giving a worst case usage of about 6% of memory.
*/
- sys.totalram >>= (18 - PAGE_SHIFT);
- max_delegations = (unsigned int) sys.totalram;
+ max_delegations = nr_free_buffer_pages() >> (20 - 2 - PAGE_SHIFT);
}

/* initialization to perform when the nfsd service is started: */
diff -puN mm/page_alloc.c~knfsd-nfsd4-vary-maximum-delegation-limit-based-on-ram-size-fix-fix-fix-fix mm/page_alloc.c
--- a/mm/page_alloc.c~knfsd-nfsd4-vary-maximum-delegation-limit-based-on-ram-size-fix-fix-fix-fix
+++ a/mm/page_alloc.c
@@ -1729,6 +1729,7 @@ 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
_
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-06-28 04:39    [W:0.136 / U:0.132 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site