于 2012-2-4 4:49, J. Bruce Fields 写道:
On Wed, Feb 01, 2012 at 04:46:56PM -0500, bfields wrote:
On Tue, Jan 31, 2012 at 09:11:48AM +0800, Mi Jinlong wrote:
Should use target = i.totalram<< (PAGE_SHIFT - 12);
target = i.totalram<< PAGE_SHIFT; and
target<<= 12;
means target = i.totalram<< (PAGE_SHIFT + 12);
Yes, thanks for catching that.
Also, splitting up the calculation as I did above risks overflow at the
first step.
I'll fix that....
Here are the fixed patches.--b.
From 87b0fc7deb5feccf93b022f6a976e8441152dbb2 Mon Sep 17 00:00:00 2001
From: "J. Bruce Fields"<bfields@xxxxxxxxxx>
Date: Mon, 30 Jan 2012 16:18:35 -0500
Subject: [PATCH 1/2] nfsd: cleanup setting of default max_block_size
Move calculation of the default into a helper function.
Get rid of an unused variable "err" while we're there.
Thanks to Mi Jinlong for catching an arithmetic error in a previous
version.
Cc: Mi Jinlong<mijinlong@xxxxxxxxxxxxxx>
Signed-off-by: J. Bruce Fields<bfields@xxxxxxxxxx>
---
fs/nfsd/nfssvc.c | 44 ++++++++++++++++++++++++--------------------
1 files changed, 24 insertions(+), 20 deletions(-)
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index eda7d7e..e9eb408 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -307,33 +307,37 @@ static void set_max_drc(void)
dprintk("%s nfsd_drc_max_mem %u \n", __func__, nfsd_drc_max_mem);
}
-int nfsd_create_serv(void)
+static int nfsd_get_default_max_blksize(void)
{
- int err = 0;
+ struct sysinfo i;
+ unsigned long long target;
+ unsigned long ret;
+
+ si_meminfo(&i);
+ target = i.totalram<< PAGE_SHIFT;
+ /*
+ * Aim for 1/4096 of memory per thread This gives 1MB on 4Gig
+ * machines, but only uses 32K on 128M machines. Bottom out at
+ * 8K on 32M and smaller. Of course, this is only a default.
+ */
+ target>>= 12;
Why don't using target = i.totalram << (PAGE_SHIFT - 12) as before?
The result of the two forms is more likely different.
Is there some other reason ?
thanks,
Mi Jinlong
+
+ ret = NFSSVC_MAXBLKSIZE;
+ while (ret> target&& ret>= 8*1024*2)
+ ret /= 2;
+ return ret;
+}
+int nfsd_create_serv(void)
+{
WARN_ON(!mutex_is_locked(&nfsd_mutex));
if (nfsd_serv) {
svc_get(nfsd_serv);
return 0;
}
- if (nfsd_max_blksize == 0) {
- /* choose a suitable default */
- struct sysinfo i;
- si_meminfo(&i);
- /* Aim for 1/4096 of memory per thread
- * This gives 1MB on 4Gig machines
- * But only uses 32K on 128M machines.
- * Bottom out at 8K on 32M and smaller.
- * Of course, this is only a default.
- */
- nfsd_max_blksize = NFSSVC_MAXBLKSIZE;
- i.totalram<<= PAGE_SHIFT - 12;
- while (nfsd_max_blksize> i.totalram&&
- nfsd_max_blksize>= 8*1024*2)
- nfsd_max_blksize /= 2;
- }
+ if (nfsd_max_blksize == 0)
+ nfsd_max_blksize = nfsd_get_default_max_blksize();
nfsd_reset_versions();
-
nfsd_serv = svc_create_pooled(&nfsd_program, nfsd_max_blksize,
nfsd_last_thread, nfsd, THIS_MODULE);
if (nfsd_serv == NULL)
@@ -341,7 +345,7 @@ int nfsd_create_serv(void)
set_max_drc();
do_gettimeofday(&nfssvc_boot); /* record boot time */
- return err;
+ return 0;
}
int nfsd_nrpools(void)
--
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