extern int xfrm_policy_unregister_afinfo(struct xfrm_policy_afinfo *afinfo);
 extern void km_policy_notify(struct xfrm_policy *xp, int dir, struct km_event *c);
 extern void km_state_notify(struct xfrm_state *x, struct km_event *c);
-#define XFRM_ACQ_EXPIRES       30
 
 struct xfrm_tmpl;
 extern int km_query(struct xfrm_state *x, struct xfrm_tmpl *t, struct xfrm_policy *pol);
 
 extern u32 sysctl_xfrm_aevent_etime;
 extern u32 sysctl_xfrm_aevent_rseqth;
 extern int sysctl_xfrm_larval_drop;
+extern u32 sysctl_xfrm_acq_expires;
 #endif
 
 ctl_table core_table[] = {
                .mode           = 0644,
                .proc_handler   = &proc_dointvec
        },
+       {
+               .ctl_name       = CTL_UNNUMBERED,
+               .procname       = "xfrm_acq_expires",
+               .data           = &sysctl_xfrm_acq_expires,
+               .maxlen         = sizeof(int),
+               .mode           = 0644,
+               .proc_handler   = &proc_dointvec
+       },
 #endif /* CONFIG_XFRM */
 #endif /* CONFIG_NET */
        {
 
 #include <linux/cache.h>
 #include <asm/uaccess.h>
 #include <linux/audit.h>
+#include <linux/cache.h>
 
 #include "xfrm_hash.h"
 
 struct sock *xfrm_nl;
 EXPORT_SYMBOL(xfrm_nl);
 
-u32 sysctl_xfrm_aevent_etime = XFRM_AE_ETIME;
+u32 sysctl_xfrm_aevent_etime __read_mostly = XFRM_AE_ETIME;
 EXPORT_SYMBOL(sysctl_xfrm_aevent_etime);
 
-u32 sysctl_xfrm_aevent_rseqth = XFRM_AE_SEQT_SIZE;
+u32 sysctl_xfrm_aevent_rseqth __read_mostly = XFRM_AE_SEQT_SIZE;
 EXPORT_SYMBOL(sysctl_xfrm_aevent_rseqth);
 
+u32 sysctl_xfrm_acq_expires __read_mostly = 30;
+
 /* Each xfrm_state may be linked to two tables:
 
    1. Hash table by (spi,daddr,ah/esp) to find SA by SPI. (input,ctl)
                                h = xfrm_spi_hash(&x->id.daddr, x->id.spi, x->id.proto, family);
                                hlist_add_head(&x->byspi, xfrm_state_byspi+h);
                        }
-                       x->lft.hard_add_expires_seconds = XFRM_ACQ_EXPIRES;
-                       x->timer.expires = jiffies + XFRM_ACQ_EXPIRES*HZ;
+                       x->lft.hard_add_expires_seconds = sysctl_xfrm_acq_expires;
+                       x->timer.expires = jiffies + sysctl_xfrm_acq_expires*HZ;
                        add_timer(&x->timer);
                        xfrm_state_num++;
                        xfrm_hash_grow_check(x->bydst.next != NULL);
                x->props.family = family;
                x->props.mode = mode;
                x->props.reqid = reqid;
-               x->lft.hard_add_expires_seconds = XFRM_ACQ_EXPIRES;
+               x->lft.hard_add_expires_seconds = sysctl_xfrm_acq_expires;
                xfrm_state_hold(x);
-               x->timer.expires = jiffies + XFRM_ACQ_EXPIRES*HZ;
+               x->timer.expires = jiffies + sysctl_xfrm_acq_expires*HZ;
                add_timer(&x->timer);
                hlist_add_head(&x->bydst, xfrm_state_bydst+h);
                h = xfrm_src_hash(daddr, saddr, family);