Jacek Galowicz [Tue, 22 Nov 2011 00:09:01 +0000 (11:09 +1100)]
lguest: switch segment-voodoo-numbers to readable symbols
When studying lguest's x86 segment descriptor code, it is not longer
necessary to have the Intel x86 architecture manual open on the page
with the segment descriptor illustration to understand the crazy
numbers assigned to both descriptor structure halves a/b.
Now the struct desc_struct's fields, like suggested by
Glauber de Oliveira Costa in 2008, are used.
Signed-off-by: Jacek Galowicz <jacek@galowicz.de> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Kevin Cernekee [Sun, 13 Nov 2011 03:08:56 +0000 (19:08 -0800)]
module: Fix performance regression on modules with large symbol tables
Commit 554bdfe5acf3715e87c8d5e25a4f9a896ac9f014 (module: reduce string
table for loaded modules) introduced an optimization to shrink the size of
the resident string table. Part of this involves calling bitmap_weight()
on the strmap bitmap once for each core symbol. strmap contains one bit
for each byte of the module's strtab.
For kernel modules with a large number of symbols, the addition of the
bitmap_weight() operation to each iteration of the add_kallsyms() loop
resulted in a significant "insmod" performance regression from 2.6.31
to 2.6.32. bitmap_weight() is expensive when the bitmap is large.
The proposed alternative optimizes the common case in this loop
(is_core_symbol() == true, and the symbol name is not a duplicate), while
penalizing the exceptional case of a duplicate symbol.
My test was run on a 600 MHz MIPS processor, using a kernel module with
15,000 "core" symbols and 10,000 symbols in .init.text. .strtab takes up
250,227 bytes.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Kevin Cernekee <cernekee@gmail.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Rusty Russell [Tue, 22 Nov 2011 00:09:00 +0000 (11:09 +1100)]
virtio: add debugging if driver doesn't kick.
Under the existing #ifdef DEBUG, check that they don't have more than
1/10 of a second between an add_buf() and a
virtqueue_notify()/virtqueue_kick_prepare() call.
We could get false positives on a really busy system, but good for
development.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Rusty Russell [Tue, 22 Nov 2011 00:09:00 +0000 (11:09 +1100)]
virtio: expose added descriptors immediately.
A virtio driver does virtqueue_add_buf() multiple times before finally
calling virtqueue_kick(); previously we only exposed the added buffers
in the virtqueue_kick() call. This means we don't need a memory
barrier in virtqueue_add_buf(), but it reduces concurrency as the
device (ie. host) can't see the buffers until the kick.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Rusty Russell [Tue, 22 Nov 2011 00:08:59 +0000 (11:08 +1100)]
virtio: support unlocked queue kick
Based on patch by Christoph for virtio_blk speedup:
Split virtqueue_kick to be able to do the actual notification
outside the lock protecting the virtqueue. This patch was
originally done by Stefan Hajnoczi, but I can't find the
original one anymore and had to recreated it from memory.
Pointers to the original or corrections for the commit message
are welcome.
Rusty Russell [Tue, 22 Nov 2011 00:08:59 +0000 (11:08 +1100)]
virtio: rename virtqueue_add_buf_gfp to virtqueue_add_buf
Remove wrapper functions. This makes the allocation type explicit in
all callers; I used GPF_KERNEL where it seemed obvious, left it at
GFP_ATOMIC otherwise.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Reviewed-by: Christoph Hellwig <hch@lst.de>
virtio pci device reset actually just does an I/O
write, which in PCI is really posted, that is it
can complete on CPU before the device has received it.
Further, interrupts might have been pending on
another CPU, so device callback might get invoked after reset.
This conflicts with how drivers use reset, which is typically:
reset
unregister
a callback running after reset completed can race with
unregister, potentially leading to use after free bugs.
Fix by flushing out the write, and flushing pending interrupts.
This assumes that device is never reset from
its vq/config callbacks, or in parallel with being
added/removed, document this assumption.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Heiko Carstens [Tue, 15 Nov 2011 09:13:24 +0000 (10:13 +0100)]
virtio: add HAS_IOMEM dependency to MMIO platform bus driver
Fix this compile error on s390:
CC [M] drivers/virtio/virtio_mmio.o
drivers/virtio/virtio_mmio.c: In function 'vm_get_features':
drivers/virtio/virtio_mmio.c:107:2: error: implicit declaration of function 'writel'
Cc: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Acked-by: Pawel Moll <pawel.moll@arm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Guenter Roeck [Tue, 22 Nov 2011 00:08:54 +0000 (11:08 +1100)]
hwmon: (lm63) Add support for LM96163
LM96163 is an enhanced version of LM63 with improved PWM resolution. Add chip
detection code as well as support for improved PWM resolution if the chip is
configured to use it.
projects / karo-tx-linux.git / log