Replace MAXPHYS by runtime variable maxphys. It is initialized from
MAXPHYS by default, but can be also adjusted with the tunable kern.maxphys.
Make b_pages[] array in struct buf flexible. Size b_pages[] for buffer
cache buffers exactly to atop(maxbcachebuf) (currently it is sized to
atop(MAXPHYS)), and b_pages[] for pbufs is sized to atop(maxphys) + 1.
The +1 for pbufs allow several pbuf consumers, among them vmapbuf(),
to use unaligned buffers still sized to maxphys, esp. when such
buffers come from userspace (*). Overall, we save significant amount
of otherwise wasted memory in b_pages[] for buffer cache buffers,
while bumping MAXPHYS to desired high value.
Eliminate all direct uses of the MAXPHYS constant in kernel and driver
sources, except a place which initialize maxphys. Some random (and
arguably weird) uses of MAXPHYS, e.g. in linuxolator, are converted
straight. Some drivers, which use MAXPHYS to size embeded structures,
get private MAXPHYS-like constant; their convertion is out of scope
for this work.
Changes to cam/, dev/ahci, dev/ata, dev/mpr, dev/mpt, dev/mvs,
dev/siis, where either submitted by, or based on changes by mav.
Suggested by: mav (*)
Reviewed by: imp, mav, imp, mckusick, scottl (intermediate versions)
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D27225
P1022 SATA controller may set the wrong CCR bit for a command completion.
This would previously cause an interrupt storm. Solve this by marking all
commands complete, and letting the end_transaction deal with the successes.
Causes no problems on P5020.
While here, fix a minor bug in collision detection. The Freescale SATA
controller only has 16 slots, not 32.
When the segment count is > 16 it spills into an 'indirect descriptor list',
which immediately follows the main table, but the indirect list is entry 15, so
needs to be skipped for the general list.
The Freescale SATA controller has many similarities to AHCI controllers, so
this driver is a heavily modified AHCI driver. Currently it seems to only
do SATA 1.0 speeds (~100-150MB/s), so there is still room for improvement.
Still to be done:
* Address erratum SATA-A-006187 -- Spread Spectrum Support (intermittent
non-recoverable transient data integrity error seen when SSC enabled).
* Linux doesn't read the log page as it hangs on the P1022. See if that's
applicable to this, and address accordingly.
* Try to determine what's holding back performance, and address it.
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D6071
