and the equivalent functionality is now provided by sendfile(2) over
posix shared memory filedescriptor.
Remove the cow member of struct vm_page, and rearrange the remaining
members. While there, make hold_count unsigned.
Requested and reviewed by: alc
Tested by: pho
Sponsored by: The FreeBSD Foundation
Approved by: re (delphij)
of relying on the tvtohz() workaround. The latter has been introduced
lately by jhb@ (r254699) in order to have a fix that can be backported
to STABLE.
Reported by: Vitja Makarov <vitja.makarov at gmail dot com>
Reviewed by: jhb (earlier version)
than using a home-rolled version. The home-rolled version could result
in shorter-than-requested sleeps.
Reported by: Vitja Makarov <vitja.makarov@gmail.com>
MFC after: 2 weeks
A blocking accept (and some other operations) waits on &so->so_timeo. Once
it wakes up, it will detect the SBS_CANTRCVMORE bit.
The error from accept() is [ECONNABORTED] which is not the nicest one -- the
thread calling accept() needs to know out-of-band what is happening.
A spurious wakeup on so->so_timeo appears harmless (sleep retried) except
when lingering on close (SO_LINGER, and in that case there is no descriptor
to call shutdown() on) so this should be fairly safe.
A shutdown() already woke up a blocked accept() for TCP sockets, but not for
Unix domain sockets. This fix is generic for all domains.
This patch was sent to -hackers@ and -net@ on April 5.
MFC after: 2 weeks
reside on their own cache line to prevent false sharing with other
nearby structures, especially for those in the .bss segment.
NB: Those mutexes and rwlocks with variables next to them that get
changed on every invocation do not benefit from their own cache line.
Actually it may be net negative because two cache misses would be
incurred in those cases.
clear its pointer to next record, since next record
belongs to the buffer, and shouldn't be leaked.
The ng_ksocket(4) used to clear this pointer itself,
but the correct place is here.
Sponsored by: Nginx, Inc
This change allows creating file descriptors with close-on-exec set in some
situations. SOCK_CLOEXEC and SOCK_NONBLOCK can be OR'ed in socket() and
socketpair()'s type parameter, and MSG_CMSG_CLOEXEC to recvmsg() makes file
descriptors (SCM_RIGHTS) atomically close-on-exec.
The numerical values for SOCK_CLOEXEC and SOCK_NONBLOCK are as in NetBSD.
MSG_CMSG_CLOEXEC is the first free bit for MSG_*.
The SOCK_* flags are not passed to MAC because this may cause incorrect
failures and can be done later via fcntl() anyway. On the other hand, audit
is expected to cope with the new flags.
For MSG_CMSG_CLOEXEC, unp_externalize() is extended to take a flags
argument.
Reviewed by: kib
int bindat(int fd, int s, const struct sockaddr *addr, socklen_t addrlen);
int connectat(int fd, int s, const struct sockaddr *name, socklen_t namelen);
which allow to bind and connect respectively to a UNIX domain socket with a
path relative to the directory associated with the given file descriptor 'fd'.
- Add manual pages for the new syscalls.
- Make the new syscalls available for processes in capability mode sandbox.
- Add capability rights CAP_BINDAT and CAP_CONNECTAT that has to be present on
the directory descriptor for the syscalls to work.
- Update audit(4) to support those two new syscalls and to handle path
in sockaddr_un structure relative to the given directory descriptor.
- Update procstat(1) to recognize the new capability rights.
- Document the new capability rights in cap_rights_limit(2).
Sponsored by: The FreeBSD Foundation
Discussed with: rwatson, jilles, kib, des
- unp_zone: kern.ipc.maxsockets limit reached
- socket_zone: kern.ipc.maxsockets limit reached
- zone_mbuf: kern.ipc.nmbufs limit reached
- zone_clust: kern.ipc.nmbclusters limit reached
- zone_jumbop: kern.ipc.nmbjumbop limit reached
- zone_jumbo9: kern.ipc.nmbjumbo9 limit reached
- zone_jumbo16: kern.ipc.nmbjumbo16 limit reached
Note that those warnings are printed not often than every five minutes and can
be globally turned off by setting sysctl/tunable vm.zone_warnings to 0.
Discussed on: arch
Obtained from: WHEEL Systems
MFC after: 2 weeks
EPROTONOSUPPORT if the address family is not supported.
- introduce pffinddomain() to find a domain by family and use it as
appropriate.
Reviewed by: glebius
kernel memory, whichever is lower. The overall mbuf related memory
limit must be set so that mbufs (and clusters of various sizes)
can't exhaust physical RAM or KVM.
The limit is set to half of the physical RAM or KVM (whichever is
lower) as the baseline. In any normal scenario we want to leave
at least half of the physmem/kvm for other kernel functions and
userspace to prevent it from swapping too easily. Via a tunable
kern.maxmbufmem the limit can be upped to at most 3/4 of physmem/kvm.
At the same time divorce maxfiles from maxusers and set maxfiles to
physpages / 8 with a floor based on maxusers. This way busy servers
can make use of the significantly increased mbuf limits with a much
larger number of open sockets.
Tidy up ordering in init_param2() and check up on some users of
those values calculated here.
Out of the overall mbuf memory limit 2K clusters and 4K (page size)
clusters to get 1/4 each because these are the most heavily used mbuf
sizes. 2K clusters are used for MTU 1500 ethernet inbound packets.
4K clusters are used whenever possible for sends on sockets and thus
outbound packets. The larger cluster sizes of 9K and 16K are limited
to 1/6 of the overall mbuf memory limit. When jumbo MTU's are used
these large clusters will end up only on the inbound path. They are
not used on outbound, there it's still 4K. Yes, that will stay that
way because otherwise we run into lots of complications in the
stack. And it really isn't a problem, so don't make a scene.
Normal mbufs (256B) weren't limited at all previously. This was
problematic as there are certain places in the kernel that on
allocation failure of clusters try to piece together their packet
from smaller mbufs.
The mbuf limit is the number of all other mbuf sizes together plus
some more to allow for standalone mbufs (ACK for example) and to
send off a copy of a cluster. Unfortunately there isn't a way to
set an overall limit for all mbuf memory together as UMA doesn't
support such a limiting.
NB: Every cluster also has an mbuf associated with it.
Two examples on the revised mbuf sizing limits:
1GB KVM:
512MB limit for mbufs
419,430 mbufs
65,536 2K mbuf clusters
32,768 4K mbuf clusters
9,709 9K mbuf clusters
5,461 16K mbuf clusters
16GB RAM:
8GB limit for mbufs
33,554,432 mbufs
1,048,576 2K mbuf clusters
524,288 4K mbuf clusters
155,344 9K mbuf clusters
87,381 16K mbuf clusters
These defaults should be sufficient for even the most demanding
network loads.
MFC after: 1 month
accept queues a new socket/connection may be added to the queue
due to a race on the ACCEPT_LOCK.
The submitted patch is slightly changed in comments, teardown
and locking order and extended with KASSERT's.
Submitted by: Vijay Singh <vijju.singh-at-gmail-dot-com>
Found by: His team.
MFC after: 1 week
overwriting the return mbuf pointer with newly received data after
a loop. Instead append the new mbuf chain to the existing one.
Fix up sb_lastrecord when dequeuing mbuf's so that sbappend_stream()
doesn't get confused.
For the remainder copy case in the mbuf delivery part deduct the
copied length len instead of the whole mbuf length. Additionally
don't depend on 'n' being being available which isn't true in the
case of MSG_PEEK.
Fix the MSG_WAITALL case by comparing against sb_hiwat. Before
it was looping for every receive as sb_lowat normally is zero.
Add comment about issue with (MSG_WAITALL | MSG_PEEK) which isn't
properly handled.
Submitted by: trociny (except for the change in last paragraph)
more appropriate named kernel options for the very distinct
send and receive path.
"options SOCKET_SEND_COW" enables VM page copy-on-write based
sending of data on an outbound socket.
NB: The COW based send mechanism is not safe and may result
in kernel crashes.
"options SOCKET_RECV_PFLIP" enables VM kernel/userspace page
flipping for special disposable pages attached as external
storage to mbufs.
Only the naming of the kernel options is changed and their
corresponding #ifdef sections are adjusted. No functionality
is added or removed.
Discussed with: alc (mechanism and limitations of send side COW)
output and replace it with a new visible sysctl kern.ipc.acceptqueue
of the same functionality. It specifies the maximum length of the
accept queue on a listen socket.
The old kern.ipc.somaxconn remains available for reading and writing
for compatibility reasons so that existing programs, scripts and
configurations continue to work. There no plans to ever remove the
orginal and now hidden kern.ipc.somaxconn.
MSG_WAITALL is set, and it is possible to do the entire receive
operation at once if we block (resid <= hiwat). Actually it might make
the recv(2) with MSG_WAITALL flag get stuck when there is enough space
in the receiver buffer to satisfy the request but not enough to open
the window closed previously due to the buffer being full.
The issue can be reproduced using the following scenario:
On the sender side do 2 send(2) requests:
1) data of size much smaller than SOBUF_SIZE (e.g. SOBUF_SIZE / 10);
2) data of size equal to SOBUF_SIZE.
On the receiver side do 2 recv(2) requests with MSG_WAITALL flag set:
1) recv() data of SOBUF_SIZE / 10 size;
2) recv() data of SOBUF_SIZE size;
We totally fill the receiver buffer with one SOBUF_SIZE/10 size request
and partial SOBUF_SIZE request. When the first request is processed we
get SOBUF_SIZE/10 free space. It is just enough to receive the rest of
bytes for the second request, and soreceive_generic() blocks in the
part that is a subject of this change waiting for the rest. But the
window was closed when the buffer was filled and to avoid silly window
syndrome it opens only when available space is larger than sb_hiwat/4
or maxseg. So it is stuck and pending data is only sent via TCP window
probes.
Discussed with: kib (long ago)
MFC after: 2 weeks
check it for MT_CONTROL type too, otherwise the assertion
"m->m_type == MT_DATA" below may be triggered by the following scenario:
- the sender sends some data (MT_DATA) and then a file descriptor
(MT_CONTROL);
- the receiver calls recv(2) with a MSG_WAITALL asking for data larger
than the receive buffer (uio_resid > hiwat).
MFC after: 2 week
socket protocol number. This is useful since the socket type can
be implemented by different protocols in the same protocol family,
e.g. SOCK_STREAM may be provided by both TCP and SCTP.
Submitted by: Jukka A. Ukkonen <jau iki fi>
PR: kern/162352
Discussed with: bz
Reviewed by: glebius
MFC after: 2 weeks
Add the sysctl debug.iosize_max_clamp, enabled by default. Setting the
sysctl to zero allows to perform the SSIZE_MAX-sized i/o requests from
the usermode.
Discussed with: bde, das (previous versions)
MFC after: 1 month
If a selinfo object is recorded (via selrecord()) and then it is
quickly destroyed, with the waiters missing the opportunity to awake,
at the next iteration they will find the selinfo object destroyed,
causing a PF#.
That happens because the selinfo interface has no way to drain the
waiters before to destroy the registered selinfo object. Also this
race is quite rare to get in practice, because it would require a
selrecord(), a poll request by another thread and a quick destruction
of the selrecord()'ed selinfo object.
Fix this by adding the seldrain() routine which should be called
before to destroy the selinfo objects (in order to avoid such case),
and fix the present cases where it might have already been called.
Sometimes, the context is safe enough to prevent this type of race,
like it happens in device drivers which installs selinfo objects on
poll callbacks. There, the destruction of the selinfo object happens
at driver detach time, when all the filedescriptors should be already
closed, thus there cannot be a race.
For this case, mfi(4) device driver can be set as an example, as it
implements a full correct logic for preventing this from happening.
Sponsored by: Sandvine Incorporated
Reported by: rstone
Tested by: pluknet
Reviewed by: jhb, kib
Approved by: re (bz)
MFC after: 3 weeks
o Move the non-blocking socket test below the SBS_CANTRCVMORE so that EOF
is correctly returned on a remote connection close.
o In the non-blocking socket test compare SS_NBIO against the so->so_state
field instead of the incorrect sb->sb_state field.
o Simplify the ENOTCONN test by removing cases that can't occur.
Submitted by: trociny (with some further tweaks by committer)
Tested by: trociny
larger than the receive buffer, we have to receive in sections.
When notifying the protocol that some data has been drained the
lock is released for a moment. Returning we block waiting for the
rest of data. There is a race, when data could arrive while the
lock was released and then the connection stalls in sbwait.
Fix this by checking for data before blocking and skip blocking
if there are some.
PR: kern/154504
Reported by: Andrey Simonenko <simon@comsys.ntu-kpi.kiev.ua>
Tested by: Andrey Simonenko <simon@comsys.ntu-kpi.kiev.ua>
Reviewed by: rwatson
Approved by: kib (co-mentor)
MFC after: 2 weeks
VNET socket push back:
try to minimize the number of places where we have to switch vnets
and narrow down the time we stay switched. Add assertions to the
socket code to catch possibly unset vnets as seen in r204147.
While this reduces the number of vnet recursion in some places like
NFS, POSIX local sockets and some netgraph, .. recursions are
impossible to fix.
The current expectations are documented at the beginning of
uipc_socket.c along with the other information there.
Sponsored by: The FreeBSD Foundation
Sponsored by: CK Software GmbH
Reviewed by: jhb
Tested by: zec
Tested by: Mikolaj Golub (to.my.trociny gmail.com)
MFC after: 2 weeks
