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From: Nadia.Derbey@bull.net
To: linux-kernel@vger.kernel.org, y-goto@jp.fujitsu.com,
	akpm@linux-foundation.org
Cc: linux-mm@kvack.org, containers@lists.linux-foundation.org,
	matthltc@us.ibm.com, cmm@us.ibm.com,
	Nadia Derbey <Nadia.Derbey@bull.net>
Subject: [PATCH 1/8] Scaling msgmni to the amount of lowmem
Date: Mon, 11 Feb 2008 15:16:47 +0100	[thread overview]
Message-ID: <20080211141813.354484000@bull.net> (raw)
In-Reply-To: <20080211141646.948191000@bull.net>

[-- Attachment #1: ipc_scale_msgmni_with_lowmem.patch --]
[-- Type: text/plain, Size: 3661 bytes --]

[PATCH 01/08]

This patch computes msg_ctlmni to make it scale with the amount of lowmem.
msg_ctlmni is now set to make the message queues occupy 1/32 of the available
lowmem.

Some cleaning has also been done for the MSGPOOL constant: the msgctl man page
says it's not used, but it also defines it as a size in bytes (the code
expresses it in Kbytes).

Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>

---
 include/linux/msg.h |   14 ++++++++++++--
 ipc/msg.c           |   37 ++++++++++++++++++++++++++++++++++++-
 2 files changed, 48 insertions(+), 3 deletions(-)

Index: linux-2.6.24-mm1/include/linux/msg.h
===================================================================
--- linux-2.6.24-mm1.orig/include/linux/msg.h	2008-02-07 15:01:38.000000000 +0100
+++ linux-2.6.24-mm1/include/linux/msg.h	2008-02-07 15:23:17.000000000 +0100
@@ -49,16 +49,26 @@ struct msginfo {
 	unsigned short  msgseg; 
 };
 
+/*
+ * Scaling factor to compute msgmni:
+ * the memory dedicated to msg queues (msgmni * msgmnb) should occupy
+ * at most 1/MSG_MEM_SCALE of the lowmem (see the formula in ipc/msg.c):
+ * up to 8MB       : msgmni = 16 (MSGMNI)
+ * 4 GB            : msgmni = 8K
+ * more than 16 GB : msgmni = 32K (IPCMNI)
+ */
+#define MSG_MEM_SCALE 32
+
 #define MSGMNI    16   /* <= IPCMNI */     /* max # of msg queue identifiers */
 #define MSGMAX  8192   /* <= INT_MAX */   /* max size of message (bytes) */
 #define MSGMNB 16384   /* <= INT_MAX */   /* default max size of a message queue */
 
 /* unused */
-#define MSGPOOL (MSGMNI*MSGMNB/1024)  /* size in kilobytes of message pool */
+#define MSGPOOL (MSGMNI * MSGMNB) /* size in bytes of message pool */
 #define MSGTQL  MSGMNB            /* number of system message headers */
 #define MSGMAP  MSGMNB            /* number of entries in message map */
 #define MSGSSZ  16                /* message segment size */
-#define __MSGSEG ((MSGPOOL*1024)/ MSGSSZ) /* max no. of segments */
+#define __MSGSEG (MSGPOOL / MSGSSZ) /* max no. of segments */
 #define MSGSEG (__MSGSEG <= 0xffff ? __MSGSEG : 0xffff)
 
 #ifdef __KERNEL__
Index: linux-2.6.24-mm1/ipc/msg.c
===================================================================
--- linux-2.6.24-mm1.orig/ipc/msg.c	2008-02-07 15:02:29.000000000 +0100
+++ linux-2.6.24-mm1/ipc/msg.c	2008-02-07 15:24:19.000000000 +0100
@@ -27,6 +27,7 @@
 #include <linux/msg.h>
 #include <linux/spinlock.h>
 #include <linux/init.h>
+#include <linux/mm.h>
 #include <linux/proc_fs.h>
 #include <linux/list.h>
 #include <linux/security.h>
@@ -78,11 +79,45 @@ static int newque(struct ipc_namespace *
 static int sysvipc_msg_proc_show(struct seq_file *s, void *it);
 #endif
 
+/*
+ * Scale msgmni with the available lowmem size: the memory dedicated to msg
+ * queues should occupy at most 1/MSG_MEM_SCALE of lowmem.
+ * This should be done staying within the (MSGMNI , IPCMNI) range.
+ */
+static void recompute_msgmni(struct ipc_namespace *ns)
+{
+	struct sysinfo i;
+	unsigned long allowed;
+
+	si_meminfo(&i);
+	allowed = (((i.totalram - i.totalhigh) / MSG_MEM_SCALE) * i.mem_unit)
+		/ MSGMNB;
+
+	if (allowed < MSGMNI) {
+		ns->msg_ctlmni = MSGMNI;
+		goto out_callback;
+	}
+
+	if (allowed > IPCMNI) {
+		ns->msg_ctlmni = IPCMNI;
+		goto out_callback;
+	}
+
+	ns->msg_ctlmni = allowed;
+
+out_callback:
+
+	printk(KERN_INFO "msgmni has been set to %d for ipc namespace %p\n",
+		ns->msg_ctlmni, ns);
+}
+
 void msg_init_ns(struct ipc_namespace *ns)
 {
 	ns->msg_ctlmax = MSGMAX;
 	ns->msg_ctlmnb = MSGMNB;
-	ns->msg_ctlmni = MSGMNI;
+
+	recompute_msgmni(ns);
+
 	atomic_set(&ns->msg_bytes, 0);
 	atomic_set(&ns->msg_hdrs, 0);
 	ipc_init_ids(&ns->ids[IPC_MSG_IDS]);

--

  reply	other threads:[~2008-02-11 14:19 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-11 14:16 [PATCH 0/8] Change default MSGMNI tunable to scale with lowmem (v3) Nadia.Derbey
2008-02-11 14:16 ` Nadia.Derbey [this message]
2008-02-16  5:59   ` [PATCH 1/8] Scaling msgmni to the amount of lowmem Andrew Morton
2008-02-18  9:19     ` Nadia Derbey
2008-02-18 13:08       ` Nadia Derbey
2008-02-19  8:50         ` [LTP] " Subrata Modak
2008-02-19 17:16           ` Nadia Derbey
2008-02-19 22:16             ` Matt Helsley
2008-02-21  8:39               ` Nadia Derbey
2008-02-21 12:36               ` Nadia Derbey
2008-02-21 13:02                 ` Nadia Derbey
2008-02-21 13:39                   ` Subrata Modak
2008-02-22  6:25                     ` Nadia Derbey
2008-02-22  8:41                       ` Subrata Modak
2008-02-20  9:44             ` Subrata Modak
2008-04-29 20:28   ` Tony Luck
2008-05-05  8:45     ` Nadia Derbey
2008-05-06 16:42       ` Luck, Tony
2008-05-06 18:05         ` Serge E. Hallyn
2008-05-07  5:37           ` Nadia Derbey
2008-05-07 13:17             ` Serge E. Hallyn
2008-05-07 18:12               ` Matt Helsley
2008-05-07  5:13         ` Nadia Derbey
2008-02-11 14:16 ` [PATCH 2/8] Scaling msgmni to the number of ipc namespaces Nadia.Derbey
2008-02-11 14:16 ` [PATCH 3/8] Defining the slab_memory_callback priority as a constant Nadia.Derbey
2008-02-11 14:16 ` [PATCH 4/8] Recomputing msgmni on memory add / remove Nadia.Derbey
2008-02-11 14:16 ` [PATCH 5/8] Invoke the ipcns notifier chain as a work item Nadia.Derbey
2008-02-11 14:16 ` [PATCH 6/8] Recomputing msgmni on ipc namespace creation/removal Nadia.Derbey
2008-02-11 14:16 ` [PATCH 7/8] Do not recompute msgmni anymore if explicitely set by user Nadia.Derbey
2008-02-11 20:24   ` Andrew Morton
2008-02-12  9:32     ` Nadia Derbey
2008-02-12  9:44       ` Andrew Morton
2008-02-12 15:15         ` Nadia Derbey
2008-02-12 19:44           ` Andrew Morton
2008-02-14 11:47             ` Nadia Derbey
2008-02-12  9:45       ` Nadia Derbey
2008-02-11 14:16 ` [PATCH 8/8] Re-enable msgmni automatic recomputing msgmni if set to negative Nadia.Derbey
2008-02-11 20:27   ` Andrew Morton
2008-02-12 11:38     ` Nadia Derbey
2008-05-20 14:28 [PATCH 1/8] Scaling msgmni to the amount of lowmem Michael Kerrisk
2008-05-20 14:45 ` Nadia Derbey
2008-05-20 14:56   ` Michael Kerrisk
2008-05-21 10:47   ` Michael Kerrisk

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