0dbd7ff3ac
Found that if we run LTP netstress test with large MSS (65K),
the first attempt from server to send data comparable to this
MSS on fastopen connection will be delayed by the probe timer.
Here is an example:
< S seq 0:0 win 43690 options [mss 65495 wscale 7 tfo cookie] length 32
> S. seq 0:0 ack 1 win 43690 options [mss 65495 wscale 7] length 0
< . ack 1 win 342 length 0
Inside tcp_sendmsg(), tcp_send_mss() returns max MSS in 'mss_now',
as well as in 'size_goal'. This results the segment not queued for
transmition until all the data copied from user buffer. Then, inside
__tcp_push_pending_frames(), it breaks on send window test and
continues with the check probe timer.
Fragmentation occurs in tcp_write_wakeup()...
+0.2 > P. seq 1:43777 ack 1 win 342 length 43776
< . ack 43777, win 1365 length 0
> P. seq 43777:65001 ack 1 win 342 options [...] length 21224
...
This also contradicts with the fact that we should bound to the half
of the window if it is large.
Fix this flaw by correctly initializing max_window. Before that, it
could have large values that affect further calculations of 'size_goal'.
Fixes:
|
||
|---|---|---|
| Documentation | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.