diff options
| -rw-r--r-- | include/linux/msg.h | 14 | ||||
| -rw-r--r-- | ipc/msg.c | 37 |
2 files changed, 48 insertions, 3 deletions
diff --git a/include/linux/msg.h b/include/linux/msg.h index 10a3d5a..6f3b8e7 100644 --- a/include/linux/msg.h +++ b/include/linux/msg.h @@ -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__ @@ -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> @@ -77,11 +78,45 @@ static int newque(struct ipc_namespace *, struct ipc_params *); 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]); |