the code was correct. erealloc9p() terminates the process
on error, but the code was handling realloc() error explicitely
and responded the request with Enomem error.
the vmware svga video card emulated by qemu (qemu -vga vmware) complains and eventually causes a panic if the rectangles aren't clipped.
messages like the following can be observed from qemu before the kernel panics:
vmsvga_update_rect: update h was < 0 (-20000)
vmsvga_update_rect: update height too large y: 10000, h: 0
vmsvga_update_rect: update w was < 0 (-20000)
vmsvga_update_rect: update width too large x: 10000, w: 0
i could only reproduce this in qemu 2.0.50 on the master branch, when using the ui and had selected 'Zoom To Fit' from the View menu.
fix bug introduced by amd64 support:
forgot to update ring index i on receive. surprisingly
this was working until there where more than one packet
to process. sorry.
ilock the controller while processing rings. this should
be fixed and use kprocs instead.
we have to make sure the *swap address* doesnt go away,
after putting the swap address in the segment pte.
after we unlock the segment, the process could be
killed or fault which would cause the swap address to
be freed *before* we write the page to disk when it
pulls the page from the cache and putswap() swap pte.
keeping a reference to the page is no good. we have
to hold on the swap address. this also has the advantage
that we can now test if the swap address is still
referenced and can avoid writing to disk.
as with the Block refcount changes, _xinc() and _xdec() arent
used anymore, so remove them.
architecure can still define ainc()/adec() when it needs them.
change Proc.nlocks from Ref to int and just use normal increment and decrelemt
as done in erik quanstros 9atom.
It is not clear why we used atomic increment in the fist place as even if we
get preempted by interrupt and scheduled before we write back the incremented
value, it shouldnt be a problem and we'll just continue where we left off as
our process is the only one that can write to it.
Yoann Padioleau found that the Mach pointer Lock.m wasnt maintained
consistently for lock() vs canlock() and ilock(). Fixed.
Use uintptr instead of ulong for maxlockpc, maxilockpc and ilockpc debug variables.
webfs forks the namespace to isolate itself from its mount
point which has the side effect that it captures the mount
of previous instances of webfs mounted on /mnt/web.
explicitely unmount the mountpoint in our namespace copy
to drop the reference.
when there are multiple readers of /dev/usbevent, we have to
serialize the processing to make sure that only one driver
is opening the devices control endpoint at a time.
to do this, we assume the device is busy after reading the
event file until the next read or clunk on the same fid.
to mark a device busy, we set the dev->aux pointer to the
fid processing a event. And the Event structure takes a
reference to the device producing the event.
the problem arised from cdc ethernet and nusb/serial sharing
the same device class, and we need to run the particular driver
to figure out if the device can be used. doing this concurrently
fails because devusb allows only one open per endpoint.
the palloc.pages array takes arround 5% of the upages which
gives us:
16GB = ~0.8GB
32GB = ~1.6GB
64GB = ~3.2GB
we only have 2GB of address space above KZERO so this will not
work for long.
instead, pageinit() was altered to accept a preallocated memory
in palloc.pages. and preallocpages() in pc64/main.c allocates the
in upages memory, mapping it in the VMAP area (which has 512GB).
the drawback is that we cannot poke at Page structures now from
/proc/n/mem as the VMAP area is not accessible from it.
Without an explicit signal for a truncation, copy propagation will
sometimes propagate a 32-bit truncation and end up overwriting uses of
the original 64-bit value.
This was independently discovered and fixed in Go. See:
http://golang.org/issue/1315https://codereview.appspot.com/6002043/
Thanks Charles Forsyth for tips and advice.
as we do system reset and reboot only from boot processor cpu0 now,
theres no need for active.rebooting conditional variable.
mpshutdown() will unconditionally park application processors and
and cpu0 boots the new kernel or calls mpshutdown() causing system
reset.
in vmware, mpshutdown() used to hang in i8042reset() when not
called from the boot processor, so instead of reseting from first
cpu that acquires the shutdown lock, we park all application
processors and let the boot processor do the reset.
