- 26 10月, 2007 1 次提交
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由 Ryousei Takano 提交于
Fix inconsistency of terms: 1) D-SACK 2) F-RTO Signed-off-by: NRyousei Takano <takano-ryousei@aist.go.jp> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 24 10月, 2007 1 次提交
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由 Chuck Lever 提交于
In some places, the result of skb_headroom() is compared to an unsigned integer, and in others, the result is compared to a signed integer. Make the comparisons consistent and correct. Signed-off-by: NChuck Lever <chuck.lever@oracle.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 18 10月, 2007 1 次提交
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由 Ilpo Järvinen 提交于
Both high-sack detection and new lowest seq variables have unnecessary zero special case which are now removed by setting safe initial seqnos. This also fixes problem which caused zero received_upto being passed to tcp_mark_lost_retrans which confused after relations within the marker loop causing incorrect TCPCB_SACKED_RETRANS clearing. The problem was noticed because of a performance report from TAKANO Ryousei <takano@axe-inc.co.jp>. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Acked-by: NRyousei Takano <takano-ryousei@aist.go.jp> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 16 10月, 2007 1 次提交
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由 Ilpo Järvinen 提交于
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 12 10月, 2007 7 次提交
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由 Ilpo Järvinen 提交于
This addition of lost_retrans_low to tcp_sock might be unnecessary, it's not clear how often lost_retrans worker is executed when there wasn't work to do. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
Detection implemented with lost_retrans must work also when fastpath is taken, yet most of the queue is skipped including (very likely) those retransmitted skb's we're interested in. This problem appeared when the hints got added, which removed a need to always walk over the whole write queue head. Therefore decicion for the lost_retrans worker loop entry must be separated from the sacktag processing more than it was necessary before. It turns out to be problematic to optimize the worker loop very heavily because ack_seqs of skb may have a number of discontinuity points. Maybe similar approach as currently is implemented could be attempted but that's becoming more and more complex because the trend is towards less skb walking in sacktag marker. Trying a simple work until all rexmitted skbs heve been processed approach. Maybe after(highest_sack_end_seq, tp->high_seq) checking is not sufficiently accurate and causes entry too often in no-work-to-do cases. Since that's not known, I've separated solution to that from this patch. Noticed because of report against a related problem from TAKANO Ryousei <takano@axe-inc.co.jp>. He also provided a patch to that part of the problem. This patch includes solution to it (though this patch has to use somewhat different placement). TAKANO's description and patch is available here: http://marc.info/?l=linux-netdev&m=119149311913288&w=2 ...In short, TAKANO's problem is that end_seq the loop is using not necessarily the largest SACK block's end_seq because the current ACK may still have higher SACK blocks which are later by the loop. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
Both sacked_out and fackets_out are directly known from how parameter. Since fackets_out is accurate, there's no need for recounting (sacked_out was previously unnecessarily counted in the loop anyway). Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
This is necessary for upcoming DSACK bugfix. Reduces sacktag length which is not very sad thing at all... :-) Notice that there's a need to handle out-of-mem at caller's place. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
It's on the way for future cutting of that function. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
This condition (plain R) can arise at least in recovery that is triggered after tcp_undo_loss. There isn't any reason why they should not be marked as lost, not marking makes in_flight estimator to return too large values. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
I was reading tcp_enter_loss while looking for Cedric's bug and noticed bytes_acked adjustment is missing from FRTO side. Since bytes_acked will only be used in tcp_cong_avoid, I think it's safe to assume RTO would be spurious. During FRTO cwnd will be not controlled by tcp_cong_avoid and if FRTO calls for conventional recovery, cwnd is adjusted and the result of wrong assumption is cleared from bytes_acked. If RTO was in fact spurious, we did normal ABC already and can continue without any additional adjustments. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 11 10月, 2007 29 次提交
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由 Ilpo Järvinen 提交于
Follows own function for each task principle, this is really somewhat separate task being done in sacktag. Also reduces indentation. In addition, added ack_seq local var to break some long lines & fixed coding style things. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Stephen Hemminger 提交于
Fix a bunch of sparse warnings. Mostly about 0 used as NULL pointer, and shadowed variable declarations. One notable case was that hash size should have been unsigned. Signed-off-by: NStephen Hemminger <shemminger@linux-foundation.org> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
This should no longer be necessary because fackets_out is accurate. It indicates bugs elsewhere, thus report it. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
In case somebody has a suggestion about a better place for this check, which must guarantee execution "early enough" (i.e, before the wrap can occur), I'm very open to them. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
Just came across what RFC2018 states about generation of valid SACK blocks in case of reneging. Alter comment a bit to point out clearly. IMHO, there isn't any reason to change code because the validation is there for a purpose (counters will inform user about decision TCP made if this case ever surfaces). Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
In case of ACK reordering, the SACK block might be valid in it's time but is already obsoleted since we've received another kind of confirmation about arrival of the segments through snd_una advancement of an earlier packet. I didn't bother to build distinguishing of valid and invalid SACK blocks but simply made reordered SACK blocks that are too old always not counted regardless of their "real" validity which could be determined by using the ack field of the reordered packet (won't be significant IMHO). DSACKs can very well be considered useful even in this situation, so won't do any of this for them. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
There's no reason to clear the sacktag skb hint when small part of the rexmit queue changes. Account changes (if any) instead when fragmenting/collapsing. RTO/FRTO do not touch SACKED_ACKED bits so no need to discard SACK tag hint at all. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
Most of the description that follows comes from my mail to netdev (some editing done): Main obstacle to FRTO use is its deployment as it has to be on the sender side where as wireless link is often the receiver's access link. Take initiative on behalf of unlucky receivers and enable it by default in future Linux TCP senders. Also IETF seems to interested in advancing FRTO from experimental [1]. How does FRTO help? =================== FRTO detects spurious RTOs and avoids a number of unnecessary retransmissions and a couple of other problems that can arise due to incorrect guess made at RTO (i.e., that segments were lost when they actually got delayed which is likely to occur e.g. in wireless environments with link-layer retransmission). Though FRTO cannot prevent the first (potentially unnecessary) retransmission at RTO, I suspect that it won't cost that much even if you have to pay for each bit (won't be that high percentage out of all packets after all :-)). However, usually when you have a spurious RTO, not only the first segment unnecessarily retransmitted but the *whole window*. It goes like this: all cumulative ACKs got delayed due to in-order delivery, then TCP will actually send 1.5*original cwnd worth of data in the RTO's slow-start when the delayed ACKs arrive (basically the original cwnd worth of it unnecessarily). In case one is interested in minimizing unnecessary retransmissions e.g. due to cost, those rexmissions must never see daylight. Besides, in the worst case the generated burst overloads the bottleneck buffers which is likely to significantly delay the further progress of the flow. In case of ll rexmissions, ACK compression often occurs at the same time making the burst very "sharp edged" (in that case TCP often loses most of the segments above high_seq => very bad performance too). When FRTO is enabled, those unnecessary retransmissions are fully avoided except for the first segment and the cwnd behavior after detected spurious RTO is determined by the response (one can tune that by sysctl). Basic version (non-SACK enhanced one), FRTO can fail to detect spurious RTO as spurious and falls back to conservative behavior. ACK lossage is much less significant than reordering, usually the FRTO can detect spurious RTO if at least 2 cumulative ACKs from original window are preserved (excluding the ACK that advances to high_seq). With SACK-enhanced version, the detection is quite robust. FRTO should remove the need to set a high lower bound for the RTO estimator due to delay spikes that occur relatively common in some environments (esp. in wireless/cellular ones). [1] http://www1.ietf.org/mail-archive/web/tcpm/current/msg02862.htmlSigned-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
Basically this change enables it, previously other undo_marker users were left with nothing. Reverse undo_marker logic completely to get it set right in CA_Loss. On the other hand, when spurious RTO is detected, clear it. Clearing might be too heavy for some scenarios but seems safe enough starting point for now and shouldn't have much effect except in majority of cases (if in any). By adding a new FLAG_ we avoid looping through write_queue when RTO occurs. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
Implements following cleanups: - Comment re-placement (CodingStyle) - tcp_tso_acked() local (wrapper-like) variable removal (readability) - __-types removed (IMHO they make local variables jumpy looking and just was space) - acked -> flag (naming conventions elsewhere in TCP code) - linebreak adjustments (readability) - nested if()s combined (reduced indentation) - clarifying newlines added Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
The accounting code is pretty much the same, so it's a shame we do it in two places. I'm not too sure if added fully_acked check in MTU probing is really what we want perhaps the added end_seq could be used in the after() comparison. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
In addition, fix its function comment spacing. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
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由 Ilpo Järvinen 提交于
Substraction for fackets_out is unconditional when snd_una advances, thus there's no need to do it inside the loop. Just make sure correct bounds are honored. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
In DSACK case, some events are not extraordinary, such as packet duplication generated DSACK. They can arrive easily below snd_una when undo_marker is not set (TCP being in CA_Open), counting such DSACKs amoung SACK discards will likely just mislead if they occur in some scenario when there are other problems as well. Similarly, excessively delayed packets could cause "normal" DSACKs. Therefore, separate counters are allocated for DSACK events. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
SACK processing code has been a sort of russian roulette as no validation of SACK blocks is previously attempted. Besides, it is not very clear what all kinds of broken SACK blocks really mean (e.g., one that has start and end sequence numbers reversed). So now close the roulette once and for all. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
Only thing that tiny function does is rearming the RTO (if necessary), name it accordingly. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
Makes caller side more obvious, there's no need to have a wrapper for this oneliner! Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
Previously code had IsReno/IsFack defined as macros that were local to tcp_input.c though sack_ok field has user elsewhere too for the same purpose. This changes them to static inlines as preferred according the current coding style and unifies the access to sack_ok across multiple files. Magic bitops of sack_ok for FACK and DSACK are also abstracted to functions with appropriate names. Note: - One sack_ok = 1 remains but that's self explanary, i.e., it enables sack - Couple of !IsReno cases are changed to tcp_is_sack - There were no users for IsDSack => I dropped it Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
Previously TCP had a transitional state during which reno counted segments that are already below the current window into sacked_out, which is now prevented. In addition, re-try now the unconditional S+L skb catching. This approach conservatively calls just remove_sack and leaves reset_sack() calls alone. The best solution to the whole problem would be to first calculate the new sacked_out fully (this patch does not move reno_sack_reset calls from original sites and thus does not implement this). However, that would require very invasive change to fastretrans_alert (perhaps even slicing it to two halves). Alternatively, all callers of tcp_packets_in_flight (i.e., users that depend on sacked_out) should be postponed until the new sacked_out has been calculated but it isn't any simpler alternative. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
This happens rather infrequently and is only possible during FRTO. We must not allow TCP to slip to Open state because tcp_fastretrans_alert might then not be called on it's time when FRTO has exited. This become a problem when left_out got removed and was replaced by just sacked_out. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
tcp_verify_left_out is useful for verifying S+L condition, so add it back to couple of places in where the code was not calling to tcp_sync_left_out but used own ad-hoc solution (before the tcp_sync_left_out got removed). Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
Left_out was dropped a while ago, thus leaving verifying consistency of the "left out" as only task for the function in question. Thus make it's name more appropriate. In addition, it is intentionally converted to #define instead of static inline because the location of the invariant failure is the most important thing to have if this ever triggers. I think it would have been helpful e.g. in this case where the location of the failure point had to be based on some quesswork: http://lkml.org/lkml/2007/5/2/464 ...Luckily the guesswork seems to have proved to be correct. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
tp->left_out got removed but nothing came to replace it back then (users just did addition by themselves), so add function for users now. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
It is easily calculable when needed and user are not that many after all. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
No other users exist for tcp_ecn.h. Very few things remain in tcp.h, for most TCP ECN functions callers reside within a single .c file and can be placed there. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
F-RTO does not touch SACKED_ACKED bits at all, so there is no need to recount them in tcp_enter_frto_loss. After removal of the else branch, nested ifs can be combined. This must also reset sacked_out when SACK is not in use as TCP could have received some duplicate ACKs prior RTO. To achieve that in a sane manner, tcp_reset_reno_sack was re-placed by the previous patch. Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Ilpo Järvinen 提交于
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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