linux/lib, branch v2.6.20-rc6

kobject: kobject_uevent() returns manageable value

2006-12-20T18:56:44Z

Since kobject_uevent() function does not return an integer value to indicate if its operation was completed with success or not, it is worth changing it in order to report a proper status (success or error) instead of returning void. [randy.dunlap@oracle.com: Fix inline kobject functions] Cc: Mauricio Lin Signed-off-by: Aneesh Kumar K.V Signed-off-by: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

kref refcnt and false positives

2006-12-20T18:56:43Z

With WARN_ON addition to kobject_init() [ http://kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.19/2.6.19-mm1/dont-use/broken-out/gregkh-driver-kobject-warn.patch ] I started seeing following WARNING on CPU offline followed by online on my x86_64 system. WARNING at lib/kobject.c:172 kobject_init() Call Trace: [] dump_trace+0xaa/0x3ef [] show_trace+0x3a/0x50 [] dump_stack+0x15/0x17 [] kobject_init+0x3f/0x8a [] kobject_register+0x1a/0x3e [] sysdev_register+0x5b/0xf9 [] mce_create_device+0x77/0xf4 [] mce_cpu_callback+0x3a/0xe5 [] notifier_call_chain+0x26/0x3b [] raw_notifier_call_chain+0x9/0xb [] _cpu_up+0xb4/0xdc [] cpu_up+0x2b/0x42 [] store_online+0x4a/0x72 [] sysdev_store+0x24/0x26 [] sysfs_write_file+0xcf/0xfc [] vfs_write+0xae/0x154 [] sys_write+0x47/0x6f [] system_call+0x7e/0x83 DWARF2 unwinder stuck at system_call+0x7e/0x83 Leftover inexact backtrace: This is a false positive as mce.c is unregistering/registering sysfs interfaces cleanly on hotplug. kref_put() and conditional decrement of refcnt seems to be the root cause for this and the patch below resolves the issue for me. Signed-off-by: Venkatesh Pallipadi Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

Remove stack unwinder for now

2006-12-15T16:47:51Z

It has caused more problems than it ever really solved, and is apparently not getting cleaned up and fixed. We can put it back when it's stable and isn't likely to make warning or bug events worse. In the meantime, enable frame pointers for more readable stack traces. Signed-off-by: Linus Torvalds

[PATCH] uml problems with linux/io.h

2006-12-13T17:05:52Z

Remove useless includes of linux/io.h, don't even try to build iomap_copy on uml (it doesn't have readb() et.al., so...) Signed-off-by: Al Viro Acked-by: Jeff Dike Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] SLAB: use a multiply instead of a divide in obj_to_index()

2006-12-13T17:05:49Z

When some objects are allocated by one CPU but freed by another CPU we can consume lot of cycles doing divides in obj_to_index(). (Typical load on a dual processor machine where network interrupts are handled by one particular CPU (allocating skbufs), and the other CPU is running the application (consuming and freeing skbufs)) Here on one production server (dual-core AMD Opteron 285), I noticed this divide took 1.20 % of CPU_CLK_UNHALTED events in kernel. But Opteron are quite modern cpus and the divide is much more expensive on oldest architectures : On a 200 MHz sparcv9 machine, the division takes 64 cycles instead of 1 cycle for a multiply. Doing some math, we can use a reciprocal multiplication instead of a divide. If we want to compute V = (A / B) (A and B being u32 quantities) we can instead use : V = ((u64)A * RECIPROCAL(B)) >> 32 ; where RECIPROCAL(B) is precalculated to ((1LL << 32) + (B - 1)) / B Note : I wrote pure C code for clarity. gcc output for i386 is not optimal but acceptable : mull 0x14(%ebx) mov %edx,%eax // part of the >> 32 xor %edx,%edx // useless mov %eax,(%esp) // could be avoided mov %edx,0x4(%esp) // useless mov (%esp),%ebx [akpm@osdl.org: small cleanups] Signed-off-by: Eric Dumazet Cc: Christoph Lameter Cc: David Miller Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Fix typo in new debug options.

2006-12-12T19:16:36Z

Signed-off-by: Dave Jones Signed-off-by: Adrian Bunk

[PATCH] add MODULE_* attributes to bit reversal library

2006-12-10T18:07:52Z

Add MODULE_* attributes to the new bit reversal library. Most notably MODULE_LICENSE which prevents superfluous kernel tainting. Signed-off-by: Cal Peake Signed-off-by: Linus Torvalds

[PATCH] Kconfig refactoring for better menu nesting

2006-12-10T17:55:39Z

Refactor Kconfig content to maximize nesting of menus by menuconfig and xconfig. Tested by simultaneously running `make xconfig` with and without patch, and comparing displays. Signed-off-by: Don Mullis Signed-off-by: Randy Dunlap Cc: Sam Ravnborg Cc: Roman Zippel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] fault-injection: optimize and simplify should_fail()

2006-12-08T16:29:03Z

Trivial optimization and simplification of should_fail(). Do cheaper disqualification tests first (performance gain not quantified). Simplify logic; eliminate goto. Signed-off-by: Don Mullis Cc: Akinobu Mita Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] fault-injection: Clamp debugfs stacktrace-depth to MAX_STACK_TRACE_DEPTH

2006-12-08T16:29:03Z

Clamp /debug/fail*/stacktrace-depth to MAX_STACK_TRACE_DEPTH. Ensures that a read of /debug/fail*/stacktrace-depth always returns a truthful answer. Signed-off-by: Don Mullis Cc: Akinobu Mita Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds