The address based work estimate for unmapping (for lockbreak) is and always
was horribly inefficient for sparse mappings. The problem is most simply
explained with an example:
If we find a pgd is clear, we still have to call into unmap_page_range
PGDIR_SIZE / ZAP_BLOCK_SIZE times, each time checking the clear pgd, in
order to progress the working address to the next pgd.
The fundamental way to solve the problem is to keep track of the end
address we've processed and pass it back to the higher layers.
From: Nick Piggin <npiggin@suse.de>
Modification to completely get away from address based work estimate
and instead use an abstract count, with a very small cost for empty
entries as opposed to present pages.
On 2.6.14-git2, ppc64, and CONFIG_PREEMPT=y, mapping and unmapping 1TB
of virtual address space takes 1.69s; with the following patch applied,
this operation can be done 1000 times in less than 0.01s
From: Andrew Morton <akpm@osdl.org>
With CONFIG_HUTETLB_PAGE=n:
mm/memory.c: In function `unmap_vmas':
mm/memory.c:779: warning: division by zero
Due to
zap_work -= (end - start) /
(HPAGE_SIZE / PAGE_SIZE);
So make the dummy HPAGE_SIZE non-zero
Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Since few people need the support anymore, this moves the legacy
pm_xxx functions to CONFIG_PM_LEGACY, and include/linux/pm_legacy.h.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The file_lock spinlock sits close to mostly read fields of 'struct
files_struct'
In SMP (and NUMA) environments, each time a thread wants to open or close
a file, it has to acquire the spinlock, thus invalidating the cache line
containing this spinlock on other CPUS. So other threads doing
read()/write()/... calls that use RCU to access the file table are going
to ask further memory (possibly NUMA) transactions to read again this
memory line.
Move the spinlock to another cache line, so that concurrent threads can
share the cache line containing 'count' and 'fdt' fields.
It's worth up to 9% on a microbenchmark using a 4-thread 2-package x86
machine. See
http://marc.theaimsgroup.com/?l=linux-kernel&m=112680448713342&w=2
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Patch from Richard Purdie
Add a driver for the extra GPIOs found on the Sharp SL-C1000 (Akita).
These GPIOs are found on a Maxim MAX7310 I2C i/o expander chip. A
generic GPIO driver for the MAX7310 was attempted but this mini
driver is a much simpler and much more effective solution avoiding
several issues and complexity the generic driver had (as discussed
on LKML).
The platform device is required so the device parent can be set
correctly which ensures the device is one of the last to suspend
and first to resume. Whilst the i2c suspend/resume calls can be
influenced, nothing guarantees this is easlier/later than the
subsystems the gpios are used on which are all independent of i2c
(sound, irda, video/backlight etc.).
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
On Fri, Nov 11, 2005 at 12:58:40PM -0800, David S. Miller wrote:
>
> This change:
>
> diff-tree 8ca2bdc7a9 (from feee207e44d3643d19e648aAuthor: Christoph Hellwig <hch@lst.de>
> Date: Wed Nov 9 12:07:18 2005 -0800
>
> [SPARC] sbus rtc: implement ->compat_ioctl
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: David S. Miller <davem@davemloft.net>
>
> results in the console now getting spewed on sparc64 systems
> with messages like:
>
> [ 11.968298] ioctl32(hwclock:464): Unknown cmd fd(3) cmd(401c7014){00} arg(efc
> What's happening is hwclock tries first the SBUS rtc device ioctls
> then the normal rtc driver ones.
>
> So things actually worked better when we had the SBUS rtc compat ioctl
> directly handled via the generic compat ioctl code.
>
> There are _so_ many rtc drivers in the kernel implementing the
> generic rtc ioctls that I don't think putting a ->compat_ioctl
> into all of them to fix this problem is feasible. Unless we
> write a single rtc_compat_ioctl(), export it to modules, and hook
> it into all of those somehow.
>
> But even that doesn't appear to have any pretty implementation.
>
> Any better ideas?
We had similar problems with other ioctls where userspace did things
like that. What we did there was to put the compat handler to generic
code. The patch below does that, adding a big comment about what's
going on and removing the COMPAT_IOCTL entires for these on powerpc
that not only weren't ever useful but are duplicated now aswell.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Patch from Richard Purdie
Add the core machine support for the Sharp SL-C1000 (Akita)
and enable the Kconfig selection for it.
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch adds request_queue->nr_sorted which keeps the number of
requests in the iosched and implement elv_drain_elevator which
performs forced dispatching. elv_drain_elevator checks whether
iosched actually dispatches all requests it has and prints error
message if it doesn't. As buggy forced dispatching can result in
wrong barrier operations, I think this extra check is worthwhile.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
Also introduces a sysctl option to configure the receive buffer
accounting policy to be either at socket or association level.
Default is all the associations on the same socket share the
receive buffer.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
On ia64, it is possible to get NaT Consumption Fault and a kernel panic
when initializing sctp sideeffect commands arguments. The union
sctp_arg_t contains different sized elements and when loading a smaller
sized element (32 or 16 bits), it is possible for a speculative load to
fail and result in a NaT bit set which causes a kernel crash. The easy
way to get around it is to load the largerst member of the union.
Signed-off-by: Vladislav Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The socket level timeout values are maintained in sctp_sock and
association level timeouts are in sctp_association. So there is
no need for ep->timeouts.
Signed-off-by: Vladislav Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch introduces 4-level page tables to ia64. I have run
some benchmarks and found nothing interesting. Performance has
consistently fallen within the noise range.
It also introduces a config option (setting the default to 3
levels). The config option prevents having 4 level page
tables with 64k base page size.
Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
