Date: Sat, 4 Apr 2009 15:32:23 +0000 (UTC) From: Bruce M Simpson <bms@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r190692 - head/sys/netinet Message-ID: <200904041532.n34FWNEl074651@svn.freebsd.org>
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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);
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