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Issue:
Current tsc based delay_calibration can result in significant errors in
loops_per_jiffy count when the platform events like SMIs
(System Management Interrupts that are non-maskable) are present. This could
lead to potential kernel panic(). This issue is becoming more visible with 2.6
kernel (as default HZ is 1000) and on platforms with higher SMI handling
latencies. During the boot time, SMIs are mostly used by BIOS (for things
like legacy keyboard emulation).
Description:
The psuedocode for current delay calibration with tsc based delay looks like
(0) Estimate a value for loops_per_jiffy
(1) While (loops_per_jiffy estimate is accurate enough)
(2) wait for jiffy transition (jiffy1)
(3) Note down current tsc (tsc1)
(4) loop until tsc becomes tsc1 + loops_per_jiffy
(5) check whether jiffy changed since jiffy1 or not and refine
loops_per_jiffy estimate
Consider the following cases
Case 1:
If SMIs happen between (2) and (3) above, we can end up with a
loops_per_jiffy value that is too low. This results in shorted delays and
kernel can panic () during boot (Mostly at IOAPIC timer initialization
timer_irq_works() as we don't have enough timer interrupts in a specified
interval).
Case 2:
If SMIs happen between (3) and (4) above, then we can end up with a
loops_per_jiffy value that is too high. And with current i386 code, too
high lpj value (greater than 17M) can result in a overflow in
delay.c:__const_udelay() again resulting in shorter delay and panic().
Solution:
The patch below makes the calibration routine aware of asynchronous events
like SMIs. We increase the delay calibration time and also identify any
significant errors (greater than 12.5%) in the calibration and notify it to
user.
Patch below changes both i386 and x86-64 architectures to use this
new and improved calibrate_delay_direct() routine.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This patch modifies the way pagesets in struct zone are managed.
Each zone has a per-cpu array of pagesets. So any particular CPU has some
memory in each zone structure which belongs to itself. Even if that CPU is
not local to that zone.
So the patch relocates the pagesets for each cpu to the node that is nearest
to the cpu instead of allocating the pagesets in the (possibly remote) target
zone. This means that the operations to manage pages on remote zone can be
done with information available locally.
We play a macro trick so that non-NUMA pmachines avoid the additional
pointer chase on the page allocator fastpath.
AIM7 benchmark on a 32 CPU SGI Altix
w/o patches:
Tasks jobs/min jti jobs/min/task real cpu
1 484.68 100 484.6769 12.01 1.97 Fri Mar 25 11:01:42 2005
100 27140.46 89 271.4046 21.44 148.71 Fri Mar 25 11:02:04 2005
200 30792.02 82 153.9601 37.80 296.72 Fri Mar 25 11:02:42 2005
300 32209.27 81 107.3642 54.21 451.34 Fri Mar 25 11:03:37 2005
400 34962.83 78 87.4071 66.59 588.97 Fri Mar 25 11:04:44 2005
500 31676.92 75 63.3538 91.87 742.71 Fri Mar 25 11:06:16 2005
600 36032.69 73 60.0545 96.91 885.44 Fri Mar 25 11:07:54 2005
700 35540.43 77 50.7720 114.63 1024.28 Fri Mar 25 11:09:49 2005
800 33906.70 74 42.3834 137.32 1181.65 Fri Mar 25 11:12:06 2005
900 34120.67 73 37.9119 153.51 1325.26 Fri Mar 25 11:14:41 2005
1000 34802.37 74 34.8024 167.23 1465.26 Fri Mar 25 11:17:28 2005
with slab API changes and pageset patch:
Tasks jobs/min jti jobs/min/task real cpu
1 485.00 100 485.0000 12.00 1.96 Fri Mar 25 11:46:18 2005
100 28000.96 89 280.0096 20.79 150.45 Fri Mar 25 11:46:39 2005
200 32285.80 79 161.4290 36.05 293.37 Fri Mar 25 11:47:16 2005
300 40424.15 84 134.7472 43.19 438.42 Fri Mar 25 11:47:59 2005
400 39155.01 79 97.8875 59.46 590.05 Fri Mar 25 11:48:59 2005
500 37881.25 82 75.7625 76.82 730.19 Fri Mar 25 11:50:16 2005
600 39083.14 78 65.1386 89.35 872.79 Fri Mar 25 11:51:46 2005
700 38627.83 77 55.1826 105.47 1022.46 Fri Mar 25 11:53:32 2005
800 39631.94 78 49.5399 117.48 1169.94 Fri Mar 25 11:55:30 2005
900 36903.70 79 41.0041 141.94 1310.78 Fri Mar 25 11:57:53 2005
1000 36201.23 77 36.2012 160.77 1458.31 Fri Mar 25 12:00:34 2005
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Shobhit Dayal <shobhit@calsoftinc.com>
Signed-off-by: Shai Fultheim <Shai@Scalex86.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Actually, the real support was added by some earlier patches. Now we simply
re-enable the config. option. I've actually tested it and it works well.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Audit now actually requires netlink. So make it depend on CONFIG_NET,
and remove the inline dependencies on CONFIG_NET.
Signed-off-by: Chris Wright <chrisw@osdl.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
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Signed-off-by: David Woodhouse <dwmw2@infradead.org>
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This patch is for -mm only. It should probably be included in git-audit,
and should be forwarded to Linus iff git-audit is.
It updates the audit-syscall-{entry,exit} calls to current -mm.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
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Arrange for all kernel printks to be no-ops. Only available if
CONFIG_EMBEDDED.
This patch saves about 375k on my laptop config and nearly 100k on minimal
configs.
Signed-off-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This patch eliminates all kernel BUGs, trims about 35k off the typical
kernel, and makes the system slightly faster.
Signed-off-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
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