From 73314404a9bd7106514b711cd69765b4081b6bed Mon Sep 17 00:00:00 2001
From: Justus Winter <4winter@informatik.uni-hamburg.de>
Date: Tue, 16 Dec 2014 13:36:08 +0100
Subject: ipc: tune size of cached kernel message buffers

The previous limit was 256 bytes.  That seems a little crummy by
todays standards, and we are frequently sending bigger packets
(e.g. every RPC containing a string_t on Hurd).

Use the page size for IKM_SAVED_KMSG_SIZE to make sure the page is
pinned to a single processor.

* ipc/ipc_kmsg.h (IKM_SAVED_KMSG_SIZE): Define to `PAGE_SIZE'.
---
 ipc/ipc_kmsg.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

(limited to 'ipc')

diff --git a/ipc/ipc_kmsg.h b/ipc/ipc_kmsg.h
index 07695fb..f06857a 100644
--- a/ipc/ipc_kmsg.h
+++ b/ipc/ipc_kmsg.h
@@ -92,9 +92,12 @@ extern ipc_kmsg_t	ipc_kmsg_cache[NCPUS];
 /*
  *	The size of the kernel message buffers that will be cached.
  *	IKM_SAVED_KMSG_SIZE includes overhead; IKM_SAVED_MSG_SIZE doesn't.
+ *
+ *	We use the page size for IKM_SAVED_KMSG_SIZE to make sure the
+ *	page is pinned to a single processor.
  */
 
-#define	IKM_SAVED_KMSG_SIZE	((vm_size_t) 256)
+#define	IKM_SAVED_KMSG_SIZE	PAGE_SIZE
 #define	IKM_SAVED_MSG_SIZE	ikm_less_overhead(IKM_SAVED_KMSG_SIZE)
 
 #define	ikm_alloc(size)							\
-- 
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