- 26 Apr, 2007 20 commits
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Angelo P. Castellani authored
YeAH-TCP is a sender-side high-speed enabled TCP congestion control algorithm, which uses a mixed loss/delay approach to compute the congestion window. It's design goals target high efficiency, internal, RTT and Reno fairness, resilience to link loss while keeping network elements load as low as possible. For further details look here: http://wil.cs.caltech.edu/pfldnet2007/paper/YeAH_TCP.pdfSigned-off-by: Angelo P. Castellani <angelo.castellani@gmail.con> Signed-off-by: David S. Miller <davem@davemloft.net>
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Ilpo Järvinen authored
The description is overly verbose to avoid ambiguity between "SACK enabled" and "SACK enhanced FRTO" Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
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Ilpo Järvinen authored
Implements the SACK-enhanced FRTO given in RFC4138 using the variant given in Appendix B. RFC4138, Appendix B: "This means that in order to declare timeout spurious, the TCP sender must receive an acknowledgment for non-retransmitted segment between SND.UNA and RecoveryPoint in algorithm step 3. RecoveryPoint is defined in conservative SACK-recovery algorithm [RFC3517]" The basic version of the FRTO algorithm can still be used also when SACK is enabled. To enabled SACK-enhanced version, tcp_frto sysctl is set to 2. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
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Ilpo Järvinen authored
To be honest, I'm not too sure how the reord stuff works in the first place but this seems necessary. When FRTO has been active, the one and only retransmission could be unnecessary but the state and sending order might not be what the sacktag code expects it to be (to work correctly). Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
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Ilpo Järvinen authored
TCP without FRTO would be in Loss state with small cwnd. FRTO, however, leaves cwnd (typically) to a larger value which causes ssthresh to become too large in case RTO is triggered again compared to what conventional recovery would do. Because consecutive RTOs result in only a single ssthresh reduction, RTO+cumulative ACK+RTO pattern is required to trigger this event. A large comment is included for congestion control module writers trying to figure out what CA_EVENT_FRTO handler should do because there exists a remote possibility of incompatibility between FRTO and module defined ssthresh functions. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
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Ilpo Järvinen authored
Previously RETRANS bits were cleared on the entry to FRTO. We postpone that into tcp_enter_frto_loss, which is really the place were the clearing should be done anyway. This allows simplification of the logic from a clearing loop to the head skb clearing only. Besides, the other changes made in the previous patches to tcp_use_frto made it impossible for the non-SACKed FRTO to be entered if other than the head has been rexmitted. With SACK-enhanced FRTO (and Appendix B), however, there can be a number retransmissions in flight when RTO expires (same thing could happen before this patchset also with non-SACK FRTO). To not introduce any jumpiness into the packet counting during FRTO, instead of clearing RETRANS bits from skbs during entry, do it later on. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
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Ilpo Järvinen authored
This interpretation comes from RFC4138: "If the sender implements some loss recovery algorithm other than Reno or NewReno [FHG04], the F-RTO algorithm SHOULD NOT be entered when earlier fast recovery is underway." I think the RFC means to say (especially in the light of Appendix B) that ...recovery is underway (not just fast recovery) or was underway when it was interrupted by an earlier (F-)RTO that hasn't yet been resolved (snd_una has not advanced enough). Thus, my interpretation is that whenever TCP has ever retransmitted other than head, basic version cannot be used because then the order assumptions which are used as FRTO basis do not hold. NewReno has only the head segment retransmitted at a time. Therefore, walk up to the segment that has not been SACKed, if that segment is not retransmitted nor anything before it, we know for sure, that nothing after the non-SACKed segment should be either. This assumption is valid because TCPCB_EVER_RETRANS does not leave holes but each non-SACKed segment is rexmitted in-order. Check for retrans_out > 1 avoids more expensive walk through the skb list, as we can know the result beforehand: F-RTO will not be allowed. SACKed skb can turn into non-SACked only in the extremely rare case of SACK reneging, in this case we might fail to detect retransmissions if there were them for any other than head. To get rid of that feature, whole rexmit queue would have to be walked (always) or FRTO should be prevented when SACK reneging happens. Of course RTO should still trigger after reneging which makes this issue even less likely to show up. And as long as the response is as conservative as it's now, nothing bad happens even then. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
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Ilpo Järvinen authored
FRTO controls cwnd when it still processes the ACK input or it has just reverted back to conventional RTO recovery; the normal rules apply when FRTO has reverted to standard congestion control. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
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Ilpo Järvinen authored
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
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Ilpo Järvinen authored
Because TCP is not in Loss state during FRTO recovery, fast recovery could be triggered by accident. Non-SACK FRTO is more robust than not yet included SACK-enhanced version (that can receiver high number of duplicate ACKs with SACK blocks during FRTO), at least with unidirectional transfers, but under extraordinary patterns fast recovery can be incorrectly triggered, e.g., Data loss+ACK losses => cumulative ACK with enough SACK blocks to meet sacked_out >= dupthresh condition). Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
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Ilpo Järvinen authored
Since purpose is to reduce CWND, we prevent immediate growth. This is not a major issue nor is "the correct way" specified anywhere. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
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Ilpo Järvinen authored
The FRTO detection did not care how ACK pattern affects to cwnd calculation of the conventional recovery. This caused incorrect setting of cwnd when the fallback becames necessary. The knowledge tcp_process_frto() has about the incoming ACK is now passed on to tcp_enter_frto_loss() in allowed_segments parameter that gives the number of segments that must be added to packets-in-flight while calculating the new cwnd. Instead of snd_una we use FLAG_DATA_ACKED in duplicate ACK detection because RFC4138 states (in Section 2.2): If the first acknowledgment after the RTO retransmission does not acknowledge all of the data that was retransmitted in step 1, the TCP sender reverts to the conventional RTO recovery. Otherwise, a malicious receiver acknowledging partial segments could cause the sender to declare the timeout spurious in a case where data was lost. If the next ACK after RTO is duplicate, we do not retransmit anything, which is equal to what conservative conventional recovery does in such case. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
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Ilpo Järvinen authored
Handles RFC4138 shortcoming (in step 2); it should also have case c) which ignores ACKs that are not duplicates nor advance window (opposite dir data, winupdate). Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
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Ilpo Järvinen authored
Retransmission counter assumptions are to be changed. Forcing reason to do this exist: Using sysctl in check would be racy as soon as FRTO starts to ignore some ACKs (doing that in the following patches). Userspace may disable it at any moment giving nice oops if timing is right. frto_counter would be inaccessible from userspace, but with SACK enhanced FRTO retrans_out can include other than head, and possibly leaving it non-zero after spurious RTO, boom again. Luckily, solution seems rather simple: never go directly to Open state but use Disorder instead. This does not really change much, since TCP could anyway change its state to Disorder during FRTO using path tcp_fastretrans_alert -> tcp_try_to_open (e.g., when a SACK block makes ACK dubious). Besides, Disorder seems to be the state where TCP should be if not recovering (in Recovery or Loss state) while having some retransmissions in-flight (see tcp_try_to_open), which is exactly what happens with FRTO. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
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Ilpo Järvinen authored
In case a latency spike causes more than one RTO, the later should not cause the already reduced ssthresh to propagate into the prior_ssthresh since FRTO declares all such RTOs spurious at once or none of them. In treating of ssthresh, we mimic what tcp_enter_loss() does. The previous state (in frto_counter) must be available until we have checked it in tcp_enter_frto(), and also ACK information flag in process_frto(). Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
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Ilpo Järvinen authored
Moved comments out from the body of process_frto() to the head (preferred way; see Documentation/CodingStyle). Bonus: it's much easier to read in this compacted form. FRTO algorithm and implementation is described in greater detail. For interested reader, more information is available in RFC4138. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
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Ilpo Järvinen authored
In addition, removed inline. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
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Ilpo Järvinen authored
FRTO spurious RTO detection algorithm (RFC4138) does not include response to a detected spurious RTO but can use different response algorithms. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
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Ilpo Järvinen authored
FRTO was slightly too brave... Should only clear TCPCB_SACKED_RETRANS bit. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
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Linus Torvalds authored
.. ok, enough waffling about it already. "Just do it!" Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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- 25 Apr, 2007 7 commits
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Linus Torvalds authored
* master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6: [PARPORT] SUNBPP: Fix OOPS when debugging is enabled. [SPARC] openprom: Switch to ref counting PCI API
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Linus Torvalds authored
* master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6: [NETLINK]: Infinite recursion in netlink.
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Andrew Morton authored
The packet driver is assuming (reasonably) that the (undocumented) request.errors is an errno. But it is in fact some mysterious bitfield. When things go wrong we return weird positive numbers to the VFS as pointers and it goes oops. Thanks to William Heimbigner for reporting and diagnosis. (It doesn't oops, but this driver still doesn't work for William) Cc: William Heimbigner <icxcnika@mar.tar.cc> Cc: Peter Osterlund <petero2@telia.com> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Alexey Kuznetsov authored
Reply to NETLINK_FIB_LOOKUP messages were misrouted back to kernel, which resulted in infinite recursion and stack overflow. The bug is present in all kernel versions since the feature appeared. The patch also makes some minimal cleanup: 1. Return something consistent (-ENOENT) when fib table is missing 2. Do not crash when queue is empty (does not happen, but yet) 3. Put result of lookup Signed-off-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Signed-off-by: David S. Miller <davem@davemloft.net>
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Jens Axboe authored
There's a really rare and obscure bug in CFQ, that causes a crash in cfq_dispatch_insert() due to rq == NULL. One example of the resulting oops is seen here: http://lkml.org/lkml/2007/4/15/41 Neil correctly diagnosed the situation for how this can happen: if two concurrent requests with the exact same sector number (due to direct IO or aliasing between MD and the raw device access), the alias handling will add the request to the sortlist, but next_rq remains NULL. Read the more complete analysis at: http://lkml.org/lkml/2007/4/25/57 This looks like it requires md to trigger, even though it should potentially be possible to due with O_DIRECT (at least if you edit the kernel and doctor some of the unplug calls). The fix is to move the ->next_rq update to when we add a request to the rbtree. Then we remove the possibility for a request to exist in the rbtree code, but not have ->next_rq correctly updated. Signed-off-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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YOSHIFUJI Hideaki authored
Oops, thinko. The test for accempting a RH0 was exatly the wrong way around. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Linus Torvalds authored
* master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6: [BNX2]: Fix occasional NETDEV WATCHDOG on 5709. [IPV6]: Disallow RH0 by default. [XFRM]: beet: fix pseudo header length value [TCP]: Congestion control initialization.
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- 24 Apr, 2007 13 commits
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Michael Chan authored
Tweak a register setting to prevent the tx mailbox from halting. Update version to 1.5.8. Signed-off-by: Michael Chan <mchan@broadcom.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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YOSHIFUJI Hideaki authored
A security issue is emerging. Disallow Routing Header Type 0 by default as we have been doing for IPv4. Note: We allow RH2 by default because it is harmless. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
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Ralf Baechle authored
This did cause oprofile to fail on non-multithreaded systems with more than 2 processors such as the BCM1480. Reported by Manish Lachwani (mlachwani@mvista.com). Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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Linus Torvalds authored
* 'upstream-linus' of master.kernel.org:/pub/scm/linux/kernel/git/jgarzik/netdev-2.6: drivers/net/hamradio/baycom_ser_fdx build fix usb-net/pegasus: fix pegasus carrier detection sis900: Allocate rx replacement buffer before rx operation [netdrvr] depca: handle platform_device_add() failure
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Andrew Morton authored
sparc64: drivers/net/hamradio/baycom_ser_fdx.c: In function `ser12_open': drivers/net/hamradio/baycom_ser_fdx.c:417: error: `NR_IRQS' undeclared (first us e in this function) drivers/net/hamradio/baycom_ser_fdx.c:417: error: (Each undeclared identifier is reported only once drivers/net/hamradio/baycom_ser_fdx.c:417: error: for each function it appears i n.) Cc: Folkert van Heusden <folkert@vanheusden.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jeff Garzik <jeff@garzik.org>
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Dan Williams authored
Broken by 4a1728a2 which switched the return semantics of read_mii_word() but didn't fix usage of read_mii_word() to conform to the new semantics. Setting carrier to off based on the NO_CARRIER flag is also incorrect as that flag only triggers on TX failure and therefore isn't correct when no frames are being transmitted. Since there is already a 2*HZ MII carrier check going on, defer to that. Add a TRUST_LINK_STATUS feature flag for adapters where the LINK_STATUS flag is actually correct, and use that rather than the NO_CARRIER flag. Signed-off-by: Dan Williams <dcbw@redhat.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
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Neil Horman authored
The sis900 driver appears to have a bug in which the receive routine passes the skbuff holding the received frame to the network stack before refilling the buffer in the rx ring. If a new skbuff cannot be allocated, the driver simply leaves a hole in the rx ring, which causes the driver to stop receiving frames and become non-recoverable without an rmmod/insmod according to reporters. This patch reverses that order, attempting to allocate a replacement buffer first, and receiving the new frame only if one can be allocated. If no skbuff can be allocated, the current skbuf in the rx ring is recycled, dropping the current frame, but keeping the NIC operational. Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
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Andrea Righi authored
The following patch fixes a kernel bug in depca_platform_probe(). We don't use a dynamic pointer for pldev->dev.platform_data, so it seems that the correct way to proceed if platform_device_add(pldev) fails is to explicitly set the pldev->dev.platform_data pointer to NULL, before calling the platform_device_put(pldev), or it will be kfree'ed by platform_device_release(). Signed-off-by: Jeff Garzik <jeff@garzik.org>
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git://one.firstfloor.org/home/andi/git/linux-2.6Linus Torvalds authored
* 'for-linus' of git://one.firstfloor.org/home/andi/git/linux-2.6: [PATCH] i386: Fix some warnings added by earlier patch [PATCH] x86-64: Always flush all pages in change_page_attr [PATCH] x86: Remove noreplacement option [PATCH] x86-64: make GART PTEs uncacheable
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Linus Torvalds authored
* master.kernel.org:/pub/scm/linux/kernel/git/bart/ide-2.6: Revert "adjust legacy IDE resource setting (v2)"
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Jiri Kosina authored
Commit 40b36daa introduced possibility that serial8250_backup_timeout() -> serial8250_handle_port() locks port.lock without disabling irqs, thus allowing deadlock against interrupt handler (port.lock is acquired in serial8250_interrupt()). Spotted by lockdep. Signed-off-by: Jiri Kosina <jkosina@suse.cz> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Alex Williamson <alex.williamson@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Akinobu Mita authored
Add maintainer for fault injection support. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Jiri Slaby authored
Two functions are called from __devinit context, but they are marked as __init. Fix this. Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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