svn commit: r190692 - head/sys/netinet

[Bruce M Simpson]

Author: bms
Date: Sat Apr  4 15:32:23 2009
New Revision: 190692
URL: http://svn.freebsd.org/changeset/base/190692

Log:
  Fix mbuf chain layout pessimization:
   in the case where a single mbuf is allocated due to
   m_getcl() returning NULL, we already call MH_ALIGN,
   so do not increment m->m_data in this case.
  
  Found during MLDv2 port.

Modified:
  head/sys/netinet/igmp.c

Modified: head/sys/netinet/igmp.c
==============================================================================
--- head/sys/netinet/igmp.c     Sat Apr  4 15:26:32 2009        (r190691)
+++ head/sys/netinet/igmp.c     Sat Apr  4 15:32:23 2009        (r190692)
@@ -2784,8 +2784,11 @@ igmp_v3_enqueue_group_record(struct ifqu
                m = NULL;
                m0srcs = (ifp->if_mtu - IGMP_LEADINGSPACE -
                    sizeof(struct igmp_grouprec)) / sizeof(in_addr_t);
-               if (!is_state_change && !is_group_query)
+               if (!is_state_change && !is_group_query) {
                        m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR);
+                       if (m)
+                               m->m_data += IGMP_LEADINGSPACE;
+               }
                if (m == NULL) {
                        m = m_gethdr(M_DONTWAIT, MT_DATA);
                        if (m)
@@ -2793,7 +2796,6 @@ igmp_v3_enqueue_group_record(struct ifqu
                }
                if (m == NULL)
                        return (-ENOMEM);
-               m->m_data += IGMP_LEADINGSPACE;
 
                igmp_save_context(m, ifp);
 
@@ -2909,6 +2911,8 @@ igmp_v3_enqueue_group_record(struct ifqu
                        return (-ENOMEM);
                }
                m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR);
+               if (m)
+                       m->m_data += IGMP_LEADINGSPACE;
                if (m == NULL) {
                        m = m_gethdr(M_DONTWAIT, MT_DATA);
                        if (m)
@@ -2917,7 +2921,6 @@ igmp_v3_enqueue_group_record(struct ifqu
                if (m == NULL)
                        return (-ENOMEM);
                igmp_save_context(m, ifp);
-               m->m_data += IGMP_LEADINGSPACE;
                md = m_getptr(m, 0, &off);
                pig = (struct igmp_grouprec *)(mtod(md, uint8_t *) + off);
                CTR1(KTR_IGMPV3, "%s: allocated next packet", __func__);
@@ -3063,6 +3066,8 @@ igmp_v3_enqueue_filter_change(struct ifq
                                    "%s: use previous packet", __func__);
                        } else {
                                m = m_getcl(M_DONTWAIT, MT_DATA, M_PKTHDR);
+                               if (m)
+                                       m->m_data += IGMP_LEADINGSPACE;
                                if (m == NULL) {
                                        m = m_gethdr(M_DONTWAIT, MT_DATA);
                                        if (m)
@@ -3075,7 +3080,6 @@ igmp_v3_enqueue_filter_change(struct ifq
                                }
                                m->m_pkthdr.PH_vt.vt_nrecs = 0;
                                igmp_save_context(m, ifp);
-                               m->m_data += IGMP_LEADINGSPACE;
                                m0srcs = (ifp->if_mtu - IGMP_LEADINGSPACE -
                                    sizeof(struct igmp_grouprec)) /
                                    sizeof(in_addr_t);
_______________________________________________
svn-src-all@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-all
To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"