Apparently the libstand dosfs optimization is a bit too optimistic
and did introduce possible memory corruption.
This patch is backing out the bad part and since this results in
dosfs reading full blocks now, we can also remove extra offset argument
from dv_strategy callback.
The analysis of the issue and the backout patch is provided by Mikhail Kupchik.
PR: 214423
Submitted by: Mikhail Kupchik
Reported by: Mikhail Kupchik
Reviewed by: bapt, allanjude
Approved by: allanjude (mentor)
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D8644
This change does modify devsw dv_print() to return the int value,
enabling walkers to interrupt the walk on non zero value from dv_print().
This will allow the pager_print actually to stop displaying data on
user input, and additionally pager is used in various *dev_print callbacks,
where it was missing.
For test, lsdev [-v] command should display data by screenfuls and should
stop when the key 'q' is pressed on pager prompt.
Reviewed by: allanjude
Approved by: allanjude (mentor)
Differential Revision: https://reviews.freebsd.org/D5461
The block cache implementation in loader has proven to be almost useless, and in worst case even slowing down the disk reads due to insufficient cache size and extra memory copy.
Also the current cache implementation does not cache reads from CDs, or work with zfs built on top of multiple disks.
Instead of an LRU, this code uses a simple hash (O(1) read from cache), and instead of a single global cache, a separate cache per block device.
The cache also implements limited read-ahead to increase performance.
To simplify read ahead management, the read ahead will not wrap over bcache end, so in worst case, single block physical read will be performed to fill the last block in bcache.
Booting from a virtual CD over IPMI:
0ms latency, before: 27 second, after: 7 seconds
60ms latency, before: over 12 minutes, after: under 5 minutes.
Submitted by: Toomas Soome <tsoome@me.com>
Reviewed by: delphij (previous version), emaste (previous version)
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D4713
loader on PS3 and POWER8 systems. This is reasonably portable to other
architectures, especially FDT-based ones, if similar features are useful
elsewhere.
Netboot support is missing for now and will be added in a future commit,
at which time loader.ps3 will be garbage collected.
Done at: Hackathon
