Now all contiguous regions returned from bus-dma will be aligned to the
alignment constraint and all but the last region are guaranteed to be
a multiple of the alignment in length. This also means that the relative
alignment of two adjacent bytes in the I/O stream have a difference of 1
even if they are not physically contiguous.
The old code, when needing to perform a copy in order to align data, only
copied the amount of data needed to reach the next page boundary. This
often left an unaligned end to the segment. Drivers such as Xen's blkfront
can't deal with such segments.
The downside to this approach is that, once an unaligned region is encountered,
the remainder of the I/O will be bounced. However, bouncing should be rare.
It is typically caused by non-performance critical userland programs that
don't bother to align their I/O buffers (e.g. bsdlabel). In-kernel I/O
buffers are always aligned to at least a page boundary.
Reviewed by: scottl
MFC after: 2 weeks
no superpage mappings are created within the clean submap, aligning the
start of the clean submap helps to prevent interference with kmem_alloc()'s
use of superpages.
such that a fancier thermal management algorithm can be run from user
space, but the kernel will at least ensure your machine does not either
sound like a wind tunnel or catch fire.
Although not explicitly mentioned in style(9), it allows for easier
grepping of exit points. This reverts part of r203926.
Requested by: des
Approved by: philip (mentor)
Although this file has historically been used as a dumping ground for
random functions, nowadays it only contains functions related to copying
bits {from,to} userspace and hash table utility functions.
Behold, subr_uio.c and subr_hash.c.
and will try to load it if it's not present. To better meet these
expectations, change the module name for the loopback interface from
'loop' to 'if_lo'. The loopback interface is always compiled into the
base kernel, so there are no resulting changes in kld files, etc.
Discussed with: brooks (ages ago)
MFC after: 1 week
The `name' and `newp' arguments can be marked const, because the buffers
they refer to are never changed. While there, perform some other
cleanups:
- Remove K&R from sysctl.c.
- Implement sysctlbyname() using sysctlnametomib() to prevent
duplication of an undocumented kernel interface.
- Fix some whitespace nits.
It seems the prototypes are now in sync with NetBSD as well.
du(1), cp(1) etc, to prevent the crossing of mountpoints whilst using the
commands recursively.
PR: bin/130855
Submitted by: keramida
MFC after: 1 month
but also of different types, f.e. Sun Fire V890 can be equipped with a
mix of UltraSPARC IV and IV+ CPUs, requiring different MMU initialization
and different workarounds for model specific errata. Therefore move the
CPU implementation number from a global variable to the per-CPU data.
Functions which are called before the latter is available are passed the
implementation number as a parameter now.
This file was missed in r204152.
Tx DMA burst size 2048, I beleive PCIe maximum read request size
also should match to the value of Tx DMA burst size. With this
change I can get more than 800Mbps for TCP bulk transfers.
Previously I was not able to get more than 700Mbps. If I enable TSO
it now shows 927Mbps.
but also of different types, f.e. Sun Fire V890 can be equipped with a
mix of UltraSPARC IV and IV+ CPUs, requiring different MMU initialization
and different workarounds for model specific errata. Therefore move the
CPU implementation number from a global variable to the per-CPU data.
Functions which are called before the latter is available are passed the
implementation number as a parameter now.
to make TSO work on VLAN. So if VLAN hardware tagging is disabled
explicitly clear TSO on VLAN. While I'm here remove duplicated
VLAN_CAPABILITIES call.
from IFCAP_VLAN_HWTAGGING. I think some hardwares may be able to
TSO over VLAN without VLAN hardware tagging.
Driver changes and userland support will follow.
Reviewed by: thompsa
