freebsd-dev/sbin/ifconfig
John Baldwin 82334850ea Add an external mbuf buffer type that holds multiple unmapped pages.
Unmapped mbufs allow sendfile to carry multiple pages of data in a
single mbuf, without mapping those pages.  It is a requirement for
Netflix's in-kernel TLS, and provides a 5-10% CPU savings on heavy web
serving workloads when used by sendfile, due to effectively
compressing socket buffers by an order of magnitude, and hence
reducing cache misses.

For this new external mbuf buffer type (EXT_PGS), the ext_buf pointer
now points to a struct mbuf_ext_pgs structure instead of a data
buffer.  This structure contains an array of physical addresses (this
reduces cache misses compared to an earlier version that stored an
array of vm_page_t pointers).  It also stores additional fields needed
for in-kernel TLS such as the TLS header and trailer data that are
currently unused.  To more easily detect these mbufs, the M_NOMAP flag
is set in m_flags in addition to M_EXT.

Various functions like m_copydata() have been updated to safely access
packet contents (using uiomove_fromphys()), to make things like BPF
safe.

NIC drivers advertise support for unmapped mbufs on transmit via a new
IFCAP_NOMAP capability.  This capability can be toggled via the new
'nomap' and '-nomap' ifconfig(8) commands.  For NIC drivers that only
transmit packet contents via DMA and use bus_dma, adding the
capability to if_capabilities and if_capenable should be all that is
required.

If a NIC does not support unmapped mbufs, they are converted to a
chain of mapped mbufs (using sf_bufs to provide the mapping) in
ip_output or ip6_output.  If an unmapped mbuf requires software
checksums, it is also converted to a chain of mapped mbufs before
computing the checksum.

Submitted by:	gallatin (earlier version)
Reviewed by:	gallatin, hselasky, rrs
Discussed with:	ae, kp (firewalls)
Relnotes:	yes
Sponsored by:	Netflix
Differential Revision:	https://reviews.freebsd.org/D20616
2019-06-29 00:48:33 +00:00
..
tests Merge ^/user/ngie/release-pkg-fix-tests to unbreak how test files are installed 2016-05-04 23:20:53 +00:00
af_inet6.c Update for IETF draft-ietf-6man-ipv6only-flag. 2019-03-06 23:31:42 +00:00
af_inet.c ifconfig: eliminate trailing whitespace 2019-02-26 03:34:47 +00:00
af_link.c Allow to specify PCP on packets not belonging to any VLAN. 2018-03-27 15:29:32 +00:00
af_nd6.c Update for IETF draft-ietf-6man-ipv6only-flag. 2019-03-06 23:31:42 +00:00
carp.c various: general adoption of SPDX licensing ID tags. 2017-11-27 15:37:16 +00:00
ifbridge.c various: general adoption of SPDX licensing ID tags. 2017-11-27 15:37:16 +00:00
ifclone.c Make lagg creation more fault tolerant 2018-04-17 12:54:58 +00:00
ifconfig.8 Add an external mbuf buffer type that holds multiple unmapped pages. 2019-06-29 00:48:33 +00:00
ifconfig.c Add an external mbuf buffer type that holds multiple unmapped pages. 2019-06-29 00:48:33 +00:00
ifconfig.h Make lagg creation more fault tolerant 2018-04-17 12:54:58 +00:00
iffib.c various: general adoption of SPDX licensing ID tags. 2017-11-27 15:37:16 +00:00
ifgif.c various: general adoption of SPDX licensing ID tags. 2017-11-27 15:37:16 +00:00
ifgre.c Add GRE-in-UDP encapsulation support as defined in RFC8086. 2019-04-24 09:05:45 +00:00
ifgroup.c ifconfig: eliminate trailing whitespace 2019-02-26 03:34:47 +00:00
ifieee80211.c ifconfig(8): display 802.11n rates correctly for 'roam:rate' parameter 2019-02-10 21:32:39 +00:00
ifipsec.c Update ifr_name before invoking IPSECSREQID ioctl, this fixes the case, 2018-09-22 16:30:48 +00:00
iflagg.c Select lacp egress ports based on NUMA domain 2019-05-03 14:43:21 +00:00
ifmac.c various: general adoption of SPDX licensing ID tags. 2017-11-27 15:37:16 +00:00
ifmedia.c Finish removing FDDI and tokenring media support. 2018-04-23 21:10:33 +00:00
ifpfsync.c ifconfig: fix endianness bug displaying pfsync interfaces 2019-01-28 18:34:04 +00:00
ifvlan.c spdx: initial adoption of licensing ID tags. 2017-11-18 14:26:50 +00:00
ifvxlan.c Add support for IPv6 scoped addresses to vxlan 2017-12-30 04:03:53 +00:00
Makefile Update for IETF draft-ietf-6man-ipv6only-flag. 2019-03-06 23:31:42 +00:00
Makefile.depend DIRDEPS_BUILD: Update dependencies. 2017-10-31 00:07:04 +00:00
sfp.c ifconfig(8): Display extended compliance code string for SFP transceivers 2017-12-05 18:42:07 +00:00