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  1. Apr 21, 2012
  2. Mar 23, 2012
    • Hans Verkuil's avatar
      poll: add poll_requested_events() and poll_does_not_wait() functions · 626cf236
      Hans Verkuil authored
      
      
      In some cases the poll() implementation in a driver has to do different
      things depending on the events the caller wants to poll for.  An example
      is when a driver needs to start a DMA engine if the caller polls for
      POLLIN, but doesn't want to do that if POLLIN is not requested but instead
      only POLLOUT or POLLPRI is requested.  This is something that can happen
      in the video4linux subsystem among others.
      
      Unfortunately, the current epoll/poll/select implementation doesn't
      provide that information reliably.  The poll_table_struct does have it: it
      has a key field with the event mask.  But once a poll() call matches one
      or more bits of that mask any following poll() calls are passed a NULL
      poll_table pointer.
      
      Also, the eventpoll implementation always left the key field at ~0 instead
      of using the requested events mask.
      
      This was changed in eventpoll.c so the key field now contains the actual
      events that should be polled for as set by the caller.
      
      The solution to the NULL poll_table pointer is to set the qproc field to
      NULL in poll_table once poll() matches the events, not the poll_table
      pointer itself.  That way drivers can obtain the mask through a new
      poll_requested_events inline.
      
      The poll_table_struct can still be NULL since some kernel code calls it
      internally (netfs_state_poll() in ./drivers/staging/pohmelfs/netfs.h).  In
      that case poll_requested_events() returns ~0 (i.e.  all events).
      
      Very rarely drivers might want to know whether poll_wait will actually
      wait.  If another earlier file descriptor in the set already matched the
      events the caller wanted to wait for, then the kernel will return from the
      select() call without waiting.  This might be useful information in order
      to avoid doing expensive work.
      
      A new helper function poll_does_not_wait() is added that drivers can use
      to detect this situation.  This is now used in sock_poll_wait() in
      include/net/sock.h.  This was the only place in the kernel that needed
      this information.
      
      Drivers should no longer access any of the poll_table internals, but use
      the poll_requested_events() and poll_does_not_wait() access functions
      instead.  In order to enforce that the poll_table fields are now prepended
      with an underscore and a comment was added warning against using them
      directly.
      
      This required a change in unix_dgram_poll() in unix/af_unix.c which used
      the key field to get the requested events.  It's been replaced by a call
      to poll_requested_events().
      
      For qproc it was especially important to change its name since the
      behavior of that field changes with this patch since this function pointer
      can now be NULL when that wasn't possible in the past.
      
      Any driver accessing the qproc or key fields directly will now fail to compile.
      
      Some notes regarding the correctness of this patch: the driver's poll()
      function is called with a 'struct poll_table_struct *wait' argument.  This
      pointer may or may not be NULL, drivers can never rely on it being one or
      the other as that depends on whether or not an earlier file descriptor in
      the select()'s fdset matched the requested events.
      
      There are only three things a driver can do with the wait argument:
      
      1) obtain the key field:
      
      	events = wait ? wait->key : ~0;
      
         This will still work although it should be replaced with the new
         poll_requested_events() function (which does exactly the same).
         This will now even work better, since wait is no longer set to NULL
         unnecessarily.
      
      2) use the qproc callback. This could be deadly since qproc can now be
         NULL. Renaming qproc should prevent this from happening. There are no
         kernel drivers that actually access this callback directly, BTW.
      
      3) test whether wait == NULL to determine whether poll would return without
         waiting. This is no longer sufficient as the correct test is now
         wait == NULL || wait->_qproc == NULL.
      
         However, the worst that can happen here is a slight performance hit in
         the case where wait != NULL and wait->_qproc == NULL. In that case the
         driver will assume that poll_wait() will actually add the fd to the set
         of waiting file descriptors. Of course, poll_wait() will not do that
         since it tests for wait->_qproc. This will not break anything, though.
      
         There is only one place in the whole kernel where this happens
         (sock_poll_wait() in include/net/sock.h) and that code will be replaced
         by a call to poll_does_not_wait() in the next patch.
      
         Note that even if wait->_qproc != NULL drivers cannot rely on poll_wait()
         actually waiting. The next file descriptor from the set might match the
         event mask and thus any possible waits will never happen.
      
      Signed-off-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
      Reviewed-by: default avatarJonathan Corbet <corbet@lwn.net>
      Reviewed-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      Cc: Davide Libenzi <davidel@xmailserver.org>
      Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
      Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
      Cc: David Miller <davem@davemloft.net>
      Cc: Eric Dumazet <eric.dumazet@gmail.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      626cf236
  3. Feb 24, 2012
  4. Feb 21, 2012
    • Pavel Emelyanov's avatar
      sock: Introduce the SO_PEEK_OFF sock option · ef64a54f
      Pavel Emelyanov authored
      
      
      This one specifies where to start MSG_PEEK-ing queue data from. When
      set to negative value means that MSG_PEEK works as ususally -- peeks
      from the head of the queue always.
      
      When some bytes are peeked from queue and the peeking offset is non
      negative it is moved forward so that the next peek will return next
      portion of data.
      
      When non-peeking recvmsg occurs and the peeking offset is non negative
      is is moved backward so that the next peek will still peek the proper
      data (i.e. the one that would have been picked if there were no non
      peeking recv in between).
      
      The offset is set using per-proto opteration to let the protocol handle
      the locking issues and to check whether the peeking offset feature is
      supported by the protocol the socket belongs to.
      
      Signed-off-by: default avatarPavel Emelyanov <xemul@parallels.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      ef64a54f
  5. Feb 13, 2012
  6. Feb 02, 2012
    • Li Zefan's avatar
      cgroup: remove cgroup_subsys argument from callbacks · 761b3ef5
      Li Zefan authored
      
      
      The argument is not used at all, and it's not necessary, because
      a specific callback handler of course knows which subsys it
      belongs to.
      
      Now only ->pupulate() takes this argument, because the handlers of
      this callback always call cgroup_add_file()/cgroup_add_files().
      
      So we reduce a few lines of code, though the shrinking of object size
      is minimal.
      
       16 files changed, 113 insertions(+), 162 deletions(-)
      
         text    data     bss     dec     hex filename
      5486240  656987 7039960 13183187         c928d3 vmlinux.o.orig
      5486170  656987 7039960 13183117         c9288d vmlinux.o
      
      Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      761b3ef5
  7. Jan 26, 2012
  8. Jan 22, 2012
  9. Jan 09, 2012
  10. Jan 07, 2012
    • Glauber Costa's avatar
      net: fix sock_clone reference mismatch with tcp memcontrol · f3f511e1
      Glauber Costa authored
      
      
      Sockets can also be created through sock_clone. Because it copies
      all data in the sock structure, it also copies the memcg-related pointer,
      and all should be fine. However, since we now use reference counts in
      socket creation, we are left with some sockets that have no reference
      counts. It matters when we destroy them, since it leads to a mismatch.
      
      Signed-off-by: default avatarGlauber Costa <glommer@parallels.com>
      CC: David S. Miller <davem@davemloft.net>
      CC: Greg Thelen <gthelen@google.com>
      CC: Hiroyouki Kamezawa <kamezawa.hiroyu@jp.fujitsu.com>
      CC: Laurent Chavey <chavey@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      f3f511e1
  11. Dec 23, 2011
  12. Dec 16, 2011
  13. Dec 13, 2011
  14. Nov 22, 2011
    • Neil Horman's avatar
      net: add network priority cgroup infrastructure (v4) · 5bc1421e
      Neil Horman authored
      
      
      This patch adds in the infrastructure code to create the network priority
      cgroup.  The cgroup, in addition to the standard processes file creates two
      control files:
      
      1) prioidx - This is a read-only file that exports the index of this cgroup.
      This is a value that is both arbitrary and unique to a cgroup in this subsystem,
      and is used to index the per-device priority map
      
      2) priomap - This is a writeable file.  On read it reports a table of 2-tuples
      <name:priority> where name is the name of a network interface and priority is
      indicates the priority assigned to frames egresessing on the named interface and
      originating from a pid in this cgroup
      
      This cgroup allows for skb priority to be set prior to a root qdisc getting
      selected. This is benenficial for DCB enabled systems, in that it allows for any
      application to use dcb configured priorities so without application modification
      
      Signed-off-by: default avatarNeil Horman <nhorman@tuxdriver.com>
      Signed-off-by: default avatarJohn Fastabend <john.r.fastabend@intel.com>
      CC: Robert Love <robert.w.love@intel.com>
      CC: "David S. Miller" <davem@davemloft.net>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      5bc1421e
  15. Nov 16, 2011
  16. Nov 09, 2011
    • Johannes Berg's avatar
      net: add wireless TX status socket option · 6e3e939f
      Johannes Berg authored
      
      
      The 802.1X EAPOL handshake hostapd does requires
      knowing whether the frame was ack'ed by the peer.
      Currently, we fudge this pretty badly by not even
      transmitting the frame as a normal data frame but
      injecting it with radiotap and getting the status
      out of radiotap monitor as well. This is rather
      complex, confuses users (mon.wlan0 presence) and
      doesn't work with all hardware.
      
      To get rid of that hack, introduce a real wifi TX
      status option for data frame transmissions.
      
      This works similar to the existing TX timestamping
      in that it reflects the SKB back to the socket's
      error queue with a SCM_WIFI_STATUS cmsg that has
      an int indicating ACK status (0/1).
      
      Since it is possible that at some point we will
      want to have TX timestamping and wifi status in a
      single errqueue SKB (there's little point in not
      doing that), redefine SO_EE_ORIGIN_TIMESTAMPING
      to SO_EE_ORIGIN_TXSTATUS which can collect more
      than just the timestamp; keep the old constant
      as an alias of course. Currently the internal APIs
      don't make that possible, but it wouldn't be hard
      to split them up in a way that makes it possible.
      
      Thanks to Neil Horman for helping me figure out
      the functions that add the control messages.
      
      Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
      Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
      6e3e939f
  17. Nov 08, 2011
  18. Nov 01, 2011
  19. Oct 31, 2011
    • Paul Gortmaker's avatar
      include: replace linux/module.h with "struct module" wherever possible · de477254
      Paul Gortmaker authored
      
      
      The <linux/module.h> pretty much brings in the kitchen sink along
      with it, so it should be avoided wherever reasonably possible in
      terms of being included from other commonly used <linux/something.h>
      files, as it results in a measureable increase on compile times.
      
      The worst culprit was probably device.h since it is used everywhere.
      This file also had an implicit dependency/usage of mutex.h which was
      masked by module.h, and is also fixed here at the same time.
      
      There are over a dozen other headers that simply declare the
      struct instead of pulling in the whole file, so follow their lead
      and simply make it a few more.
      
      Most of the implicit dependencies on module.h being present by
      these headers pulling it in have been now weeded out, so we can
      finally make this change with hopefully minimal breakage.
      
      Signed-off-by: default avatarPaul Gortmaker <paul.gortmaker@windriver.com>
      de477254
  20. Aug 18, 2011
  21. Jul 08, 2011
  22. Jul 07, 2011
  23. Jun 28, 2011
  24. Jun 27, 2011
  25. Jun 07, 2011
  26. Apr 07, 2011
  27. Apr 05, 2011
    • Tom Herbert's avatar
      net: Allow no-cache copy from user on transmit · c6e1a0d1
      Tom Herbert authored
      
      
      This patch uses __copy_from_user_nocache on transmit to bypass data
      cache for a performance improvement.  skb_add_data_nocache and
      skb_copy_to_page_nocache can be called by sendmsg functions to use
      this feature, initial support is in tcp_sendmsg.  This functionality is
      configurable per device using ethtool.
      
      Presumably, this feature would only be useful when the driver does
      not touch the data.  The feature is turned on by default if a device
      indicates that it does some form of checksum offload; it is off by
      default for devices that do no checksum offload or indicate no checksum
      is necessary.  For the former case copy-checksum is probably done
      anyway, in the latter case the device is likely loopback in which case
      the no cache copy is probably not beneficial.
      
      This patch was tested using 200 instances of netperf TCP_RR with
      1400 byte request and one byte reply.  Platform is 16 core AMD x86.
      
      No-cache copy disabled:
         672703 tps, 97.13% utilization
         50/90/99% latency:244.31 484.205 1028.41
      
      No-cache copy enabled:
         702113 tps, 96.16% utilization,
         50/90/99% latency 238.56 467.56 956.955
      
      Using 14000 byte request and response sizes demonstrate the
      effects more dramatically:
      
      No-cache copy disabled:
         79571 tps, 34.34 %utlization
         50/90/95% latency 1584.46 2319.59 5001.76
      
      No-cache copy enabled:
         83856 tps, 34.81% utilization
         50/90/95% latency 2508.42 2622.62 2735.88
      
      Note especially the effect on latency tail (95th percentile).
      
      This seems to provide a nice performance improvement and is
      consistent in the tests I ran.  Presumably, this would provide
      the greatest benfits in the presence of an application workload
      stressing the cache and a lot of transmit data happening.
      
      Signed-off-by: default avatarTom Herbert <therbert@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      c6e1a0d1
  28. Mar 31, 2011
  29. Feb 22, 2011
  30. Jan 30, 2011
    • Eric W. Biederman's avatar
      net: Add compat ioctl support for the ipv4 multicast ioctl SIOCGETSGCNT · 709b46e8
      Eric W. Biederman authored
      
      
      SIOCGETSGCNT is not a unique ioctl value as it it maps tio SIOCPROTOPRIVATE +1,
      which unfortunately means the existing infrastructure for compat networking
      ioctls is insufficient.  A trivial compact ioctl implementation would conflict
      with:
      
      SIOCAX25ADDUID
      SIOCAIPXPRISLT
      SIOCGETSGCNT_IN6
      SIOCGETSGCNT
      SIOCRSSCAUSE
      SIOCX25SSUBSCRIP
      SIOCX25SDTEFACILITIES
      
      To make this work I have updated the compat_ioctl decode path to mirror the
      the normal ioctl decode path.  I have added an ipv4 inet_compat_ioctl function
      so that I can have ipv4 specific compat ioctls.   I have added a compat_ioctl
      function into struct proto so I can break out ioctls by which kind of ip socket
      I am using.  I have added a compat_raw_ioctl function because SIOCGETSGCNT only
      works on raw sockets.  I have added a ipmr_compat_ioctl that mirrors the normal
      ipmr_ioctl.
      
      This was necessary because unfortunately the struct layout for the SIOCGETSGCNT
      has unsigned longs in it so changes between 32bit and 64bit kernels.
      
      This change was sufficient to run a 32bit ip multicast routing daemon on a
      64bit kernel.
      
      Reported-by: default avatarBill Fenner <fenner@aristanetworks.com>
      Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      709b46e8
  31. Jan 19, 2011
  32. Jan 10, 2011
  33. Dec 16, 2010
    • Octavian Purdila's avatar
      net: fix nulls list corruptions in sk_prot_alloc · fcbdf09d
      Octavian Purdila authored
      
      
      Special care is taken inside sk_port_alloc to avoid overwriting
      skc_node/skc_nulls_node. We should also avoid overwriting
      skc_bind_node/skc_portaddr_node.
      
      The patch fixes the following crash:
      
       BUG: unable to handle kernel paging request at fffffffffffffff0
       IP: [<ffffffff812ec6dd>] udp4_lib_lookup2+0xad/0x370
       [<ffffffff812ecc22>] __udp4_lib_lookup+0x282/0x360
       [<ffffffff812ed63e>] __udp4_lib_rcv+0x31e/0x700
       [<ffffffff812bba45>] ? ip_local_deliver_finish+0x65/0x190
       [<ffffffff812bbbf8>] ? ip_local_deliver+0x88/0xa0
       [<ffffffff812eda35>] udp_rcv+0x15/0x20
       [<ffffffff812bba45>] ip_local_deliver_finish+0x65/0x190
       [<ffffffff812bbbf8>] ip_local_deliver+0x88/0xa0
       [<ffffffff812bb2cd>] ip_rcv_finish+0x32d/0x6f0
       [<ffffffff8128c14c>] ? netif_receive_skb+0x99c/0x11c0
       [<ffffffff812bb94b>] ip_rcv+0x2bb/0x350
       [<ffffffff8128c14c>] netif_receive_skb+0x99c/0x11c0
      
      Signed-off-by: default avatarLeonard Crestez <lcrestez@ixiacom.com>
      Signed-off-by: default avatarOctavian Purdila <opurdila@ixiacom.com>
      Acked-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      fcbdf09d
  34. Dec 10, 2010
    • Eric Dumazet's avatar
      net: optimize INET input path further · 68835aba
      Eric Dumazet authored
      
      
      Followup of commit b178bb3d (net: reorder struct sock fields)
      
      Optimize INET input path a bit further, by :
      
      1) moving sk_refcnt close to sk_lock.
      
      This reduces number of dirtied cache lines by one on 64bit arches (and
      64 bytes cache line size).
      
      2) moving inet_daddr & inet_rcv_saddr at the beginning of sk
      
      (same cache line than hash / family / bound_dev_if / nulls_node)
      
      This reduces number of accessed cache lines in lookups by one, and dont
      increase size of inet and timewait socks.
      inet and tw sockets now share same place-holder for these fields.
      
      Before patch :
      
      offsetof(struct sock, sk_refcnt) = 0x10
      offsetof(struct sock, sk_lock) = 0x40
      offsetof(struct sock, sk_receive_queue) = 0x60
      offsetof(struct inet_sock, inet_daddr) = 0x270
      offsetof(struct inet_sock, inet_rcv_saddr) = 0x274
      
      After patch :
      
      offsetof(struct sock, sk_refcnt) = 0x44
      offsetof(struct sock, sk_lock) = 0x48
      offsetof(struct sock, sk_receive_queue) = 0x68
      offsetof(struct inet_sock, inet_daddr) = 0x0
      offsetof(struct inet_sock, inet_rcv_saddr) = 0x4
      
      compute_score() (udp or tcp) now use a single cache line per ignored
      item, instead of two.
      
      Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      68835aba
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