unnecessarily by a user thread waiting to run on a specific CPU after
calling sched_bind().
Reviewed by: rstone
Approved by: emaste (co-mentor)
Sponsored by: Sandvine Incorporated
MFC after: 1 week
submap. Otherwise, after r246204, the auto-scaling logic in kern_malloc.c
tries to create a kmem submap that consumes the entire kernel map on a
Pandaboard with 1 GB of RAM.
Tested by: gonzo
machine to another. Therefore, VM_MAX_KERNEL_ADDRESS can't be a constant.
Instead, #define it to be a variable, vm_max_kernel_address, just like we
do on sparc64.
Reviewed by: kib
Tested by: ian
why it will now be the default.
- Bump protocol version to 2 and add backward compatibility for version 1.
- Allow to specify hosts by kern.hostid as well (in addition to hostname and
kern.hostuuid) in configuration file.
Sponsored by: Panzura
Tested by: trociny
is excessive. Postpone the flush of the fsinfo to VFS_SYNC(),
remembering the need for update with the flag MSDOSFS_FSIMOD, stored
in pm_flags.
FAT32 specification describes both FSI_Free_Count and FSI_Nxt_Free as
the advisory hints, not requiring them to be correct.
Based on the patch from bde, modified by me.
Reviewed by: bde
MFC after: 2 weeks
Microoptimize i8254 one-shot operation mode (disabled by default to allow
timecounter functionality) by not writing to mode and MSB registers when
it is not required. This saves several microseconds of CPU time per call,
reducing minimal measured interrupts interval to 19.5us.
on a core, when the core was stopped, by calling kgdb_trgt_core_pcb().
This has 2 advantages:
1. We don't need to include a machine-specific header anymore and as
such kthr.c is truly machine independent. This allows the code to
be used in a cross-debugger.
2. We don't need to lookup stoppcbs in generic code when it's an
inherently target-spicific symbol. It does not exist for ia64.
Implement kgdb_trgt_core_pcb() for all architectures, except ia64, by
calling a common function called kgdb_trgt_stop_pcb(). This function
differs from kgdb_trgt_core_pcb() in that it gets the size of the PCB
structure as an argument and as such remains machine independent.
On ia64 the PCB for stopped cores is in the PCPU structure itself.
This for better scaling. The implementation of kgdb_trgt_core_pcb()
for ia64 uses the cpuid_to_pcpu[] array to to obtain the address of
the PCB structure.
points to the TLS in user space and points to the PCPU structure in
the kernel. The race is the result of having the exception handler on
the one hand and the RPC system call entry on the other. The EPC
syscall path is non-atomic in that interrupts are enabled while the
two stacks are switched. The register stack is switched last as that
is the stack used to determine whether we're going back to user space
by the exception handler. If we go back to user space, we restore r13,
otherwise we leave r13 alone. The EPC syscall path however set r13 to
the PCPU structure *before* switching the register stack, which means
that there was a window in which the exception handler would restore
r13 when it was already pointing to the PCPU structure. This is fatal
when the exception happened on CPU x, but left from the exception on
anotehr CPU. In that case r13 would point to the PCPU of the CPU the
thread was running on. This immediately results in getting the wrong
value for curthread.
The fix is to make sure we assign r13 *after* we set ar.bspstore to
point to the kernel register stack for the thread.
SDHCI driver
Suggested by: Daisuke Aoyama
- Set initilization sequence frequency to 8MHz. It should fix Data CRC
errors. Standard requires initialization sequence to be executed
at 400KHz but on this hardware low frequncies seems to cause
Data CRC errors.
Value was derived from analyzing hardware signals after
Raspberry Pi is powered up. Before any data is read though DATA line
adapter's clock frequency is changed to 8MHz.
Modern cards should function fine at 8MHz but for older MMC cards it
can be overriden by setting hw.bcm2835.sdhci.min_freq tunable.
- Replace divisor numbers with more descirptive names
- Properly calculate minimum frequency for SDHCI 3.0
- Properly calculate frequency for SDHCI 3.0 in mmcbr_set_clock
- Add min_freq method to sdhci_if.m and provide default
implementation. By re-implementing this method hardware
drivers can control frequency controller operates when
executing initialization sequence
actually do have to reinitialise the RX side of things after an RX
descriptor EOL error.
* Revert a change of mine from quite a while ago - don't shortcut the
RX initialisation path. There's a RX FIFO bug in the earlier chips
(I'm not sure when it was fixed in this series, but it's fixed
with the AR9380 and later) which causes the same RX descriptor to
be written to over and over. This causes the descriptor to be
marked as "done", and this ends up causing the whole RX path to
go very strange. This should fixed the "kickpcu; handled X packets"
message spam where "X" is consistently small.
When a cylinder group runs short of inodes, a new block for inodes is
allocated, zero'ed, and written to the disk. The zero'ed inodes must
be on the disk before the cylinder group can be updated to claim them.
If the cylinder group claiming the new inodes were written before the
zero'ed block of inodes, the system could crash with the filesystem in
an unrecoverable state.
Rather than adding a soft updates dependency to ensure that the new
inode block is written before it is claimed by the cylinder group
map, we just do a barrier write of the zero'ed inode block to ensure
that it will get written before the updated cylinder group map can
be written. This change should only slow down bulk loading of newly
created filesystems since that is the primary time that new inode
blocks need to be created.
Reported by: Robert Watson
Reviewed by: kib
Tested by: Peter Holm
write is a disk write request that tells the disk that the buffer
being written must be committed to the media along with any writes
that preceeded it before any future blocks may be written to the drive.
Barrier writes are provided by adding the functions bbarrierwrite
(bwrite with barrier) and babarrierwrite (bawrite with barrier).
Following a bbarrierwrite the client knows that the requested buffer
is on the media. It does not ensure that buffers written before that
buffer are on the media. It only ensure that buffers written before
that buffer will get to the media before any buffers written after
that buffer. A flush command must be sent to the disk to ensure that
all earlier written buffers are on the media.
Reviewed by: kib
Tested by: Peter Holm
