This patch converts the parisc architecture to use the generic
read_persistent_clock and update_persistent_clock interfaces, reducing
the amount of arch specific code we have to maintain, and allowing for
further cleanups in the future.
I have not built or tested this patch, so help from arch maintainers
would be appreciated.
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
__ldcw_align() can directly access the slock member of struct arch_spinlock_t
instead of using an ugly cast.
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
Add CONFIG_DEBUG_STRICT_USER_COPY_CHECKS, copied from the x86
implementation. Tested with 32 and 64bit kernel.
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
Assign tty only if line is not NULL.
[akpm@linux-foundation.org: simplification]
Signed-off-by: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The old anon_vma code can lead to scalability issues with heavily forking
workloads. Specifically, each anon_vma will be shared between the parent
process and all its child processes.
In a workload with 1000 child processes and a VMA with 1000 anonymous
pages per process that get COWed, this leads to a system with a million
anonymous pages in the same anon_vma, each of which is mapped in just one
of the 1000 processes. However, the current rmap code needs to walk them
all, leading to O(N) scanning complexity for each page.
This can result in systems where one CPU is walking the page tables of
1000 processes in page_referenced_one, while all other CPUs are stuck on
the anon_vma lock. This leads to catastrophic failure for a benchmark
like AIM7, where the total number of processes can reach in the tens of
thousands. Real workloads are still a factor 10 less process intensive
than AIM7, but they are catching up.
This patch changes the way anon_vmas and VMAs are linked, which allows us
to associate multiple anon_vmas with a VMA. At fork time, each child
process gets its own anon_vmas, in which its COWed pages will be
instantiated. The parents' anon_vma is also linked to the VMA, because
non-COWed pages could be present in any of the children.
This reduces rmap scanning complexity to O(1) for the pages of the 1000
child processes, with O(N) complexity for at most 1/N pages in the system.
This reduces the average scanning cost in heavily forking workloads from
O(N) to 2.
The only real complexity in this patch stems from the fact that linking a
VMA to anon_vmas now involves memory allocations. This means vma_adjust
can fail, if it needs to attach a VMA to anon_vma structures. This in
turn means error handling needs to be added to the calling functions.
A second source of complexity is that, because there can be multiple
anon_vmas, the anon_vma linking in vma_adjust can no longer be done under
"the" anon_vma lock. To prevent the rmap code from walking up an
incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit
flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h
to make sure it is impossible to compile a kernel that needs both symbolic
values for the same bitflag.
Some test results:
Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test
box with 16GB RAM and not quite enough IO), the system ends up running
>99% in system time, with every CPU on the same anon_vma lock in the
pageout code.
With these changes, AIM7 hits the cross-over point around 29.7k users.
This happens with ~99% IO wait time, there never seems to be any spike in
system time. The anon_vma lock contention appears to be resolved.
[akpm@linux-foundation.org: cleanups]
Signed-off-by: Rik van Riel <riel@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rename for_each_bit to for_each_set_bit in the kernel source tree. To
permit for_each_clear_bit(), should that ever be added.
The patch includes a macro to map the old for_each_bit() onto the new
for_each_set_bit(). This is a (very) temporary thing to ease the migration.
[akpm@linux-foundation.org: add temporary for_each_bit()]
Suggested-by: Alexey Dobriyan <adobriyan@gmail.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Artem Bityutskiy <dedekind@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix missing kernel-doc notation in mtrr/main.c:
Warning(arch/x86/kernel/cpu/mtrr/main.c:152): No description found for parameter 'info'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'perf-probes-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: Issue at least one memory barrier in stop_machine_text_poke()
perf probe: Correct probe syntax on command line help
perf probe: Add lazy line matching support
perf probe: Show more lines after last line
perf probe: Check function address range strictly in line finder
perf probe: Use libdw callback routines
perf probe: Use elfutils-libdw for analyzing debuginfo
perf probe: Rename probe finder functions
perf probe: Fix bugs in line range finder
perf probe: Update perf probe document
perf probe: Do not show --line option without dwarf support
kprobes: Add documents of jump optimization
kprobes/x86: Support kprobes jump optimization on x86
x86: Add text_poke_smp for SMP cross modifying code
kprobes/x86: Cleanup save/restore registers
kprobes/x86: Boost probes when reentering
kprobes: Jump optimization sysctl interface
kprobes: Introduce kprobes jump optimization
kprobes: Introduce generic insn_slot framework
kprobes/x86: Cleanup RELATIVEJUMP_INSTRUCTION to RELATIVEJUMP_OPCODE
This implements perf_event support for the Freescale embedded performance
monitor, based on the existing perf_event.c that supports server/classic
chips.
Some limitations:
- Performance monitor interrupts are regular EE interrupts, and thus you
can't profile places with interrupts disabled. We may want to implement
soft IRQ-disabling, with perfmon interrupts exempted and treated as NMIs.
- When trying to schedule multiple event groups at once, and using
restricted events, situations could arise where scheduling fails even
though it would be possible. Consider three groups, each with two events.
One group has restricted events, the others don't. The two non-restricted
groups are scheduled, then one is removed, which happens to occupy the two
counters that can't do restricted events. The remaining non-restricted
group will not be moved to the non-restricted-capable counters to make
room if the restricted group tries to be scheduled.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Commit 58bac7b8de failed to move the two
PLL files s3c2440-pll-12000000.c and s3c2440-pll-16934400.c, so place
these in arch/arm/mach-s3c2440 to fix this commit up.
As a note, these are not built by the default configuration and thus the
failure to move wasn't spotted until much later.
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
john stultz
Robert P. J. Day
Helge Deller
Frans Pop
Kyle McMartin
Daisuke HATAYAMA
H Hartley Sweeten
WANG Cong
Alexander Beregalov
Roel Kluin
FUJITA Tomonori
Rik van Riel
Akinobu Mita
Mika Westerberg
Linus Torvalds
Randy Dunlap
Scott Wood
Ben Dooks