CVS commit: src/sys

["Jaromir Dolecek" <jdolecek%netbsd.org@localhost>]

Module Name:    src
Committed By:   jdolecek
Date:           Sun Jun 10 17:54:51 UTC 2018

Modified Files:
        src/sys/kern: sys_pipe.c
        src/sys/sys: pipe.h

Log Message:
convert the (still disabled) 'direct write' for pipes to use the
experimental PMAP_DIRECT if available; the direct code paths now survive
longer than the pmap_enter() variant, but still triggers panic during
build.sh tools run; remove some obsolete sysctls

add some XXXs to mark places which need attention to make this more stable

Note: the loan case is now actually significantly slower than the
non-loan case on MP systems, due to synchronous IPIs triggered by
marking the page read-only by uvm_loan(); this is being discussed
in the email thread
https://mail-index.netbsd.org/tech-kern/2018/05/21/msg023441.html

that is basically the same issue due to which loaning was disabled
for sosend()


To generate a diff of this commit:
cvs rdiff -u -r1.145 -r1.146 src/sys/kern/sys_pipe.c
cvs rdiff -u -r1.34 -r1.35 src/sys/sys/pipe.h

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.