Re: Re: [PATCH] SGI 905314 (1/2): make NFSSVC_MAXBLKSIZE depend on PAGE_SIZE

[Greg Banks <gnb@melbourne.sgi.com>]

Neil Brown wrote:
> 
> What you you think of simply:
> 
>    #define NFSSVC_MAXBLKSIZE (PAGE_SIZE * 2)
> 

It's not that simple; the ia64 port can be configured for 64K pages,
which would result in nfsd reporting 128K for wtmax on UDP.

Here's a patch which is closer to that simple ideal ;-)

--- /usr/tmp/TmpDir.26244-0/linux/linux/include/linux/nfsd/const.h_1.5	Mon Dec  1
10:24:10 2003
+++ linux/include/linux/nfsd/const.h	Mon Dec  1 10:24:11 2003
@@ -12,6 +12,7 @@
 #include <linux/nfs.h>
 #include <linux/nfs2.h>
 #include <linux/nfs3.h>
+#include <asm/page.h>
 
 /*
  * Maximum protocol version supported by knfsd
@@ -19,9 +20,16 @@
 #define NFSSVC_MAXVERS		3
 
 /*
- * Maximum blocksize supported by daemon currently at 8K
+ * Maximum blocksize supported by daemon.  We want the largest
+ * value which 1) fits in a UDP datagram less some headers
+ * 2) is a multiple of page size 3) can be successfully kmalloc()ed
+ * by each nfsd.   
  */
-#define NFSSVC_MAXBLKSIZE	(8*1024)
+#if PAGE_SIZE > (16*1024)
+#define NFSSVC_MAXBLKSIZE	(32*1024)
+#else
+#define NFSSVC_MAXBLKSIZE	(2*PAGE_SIZE)
+#endif
 
 #ifdef __KERNEL__
 


Greg.
-- 
Greg Banks, R&D Software Engineer, SGI Australian Software Group.
I don't speak for SGI.


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