- 29 10月, 2009 1 次提交
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由 Tejun Heo 提交于
This patch updates percpu related symbols in xen such that percpu symbols are unique and don't clash with local symbols. This serves two purposes of decreasing the possibility of global percpu symbol collision and allowing dropping per_cpu__ prefix from percpu symbols. * arch/x86/xen/smp.c, arch/x86/xen/time.c, arch/ia64/xen/irq_xen.c: add xen_ prefix to percpu variables * arch/ia64/xen/time.c: add xen_ prefix to percpu variables, drop processed_ prefix and make them static Partly based on Rusty Russell's "alloc_percpu: rename percpu vars which cause name clashes" patch. Signed-off-by: NTejun Heo <tj@kernel.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Chris Wright <chrisw@sous-sol.org>
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- 02 10月, 2009 4 次提交
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由 Tejun Heo 提交于
Unlike other archs, ia64 reserves space for percpu areas during early memory initialization. These areas occupy a contiguous region indexed by cpu number on contiguous memory model or are grouped by node on discontiguous memory model. As allocation and initialization are done by the arch code, all that setup_per_cpu_areas() needs to do is communicating the determined layout to the percpu allocator. This patch implements setup_per_cpu_areas() for both contig and discontig memory models and drops HAVE_LEGACY_PER_CPU_AREA. Please note that for contig model, the allocation itself is modified only to allocate for possible cpus instead of NR_CPUS. As dynamic percpu allocator can handle non-direct mapping, there's no reason to allocate memory for cpus which aren't possible. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NTony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: linux-ia64 <linux-ia64@vger.kernel.org>
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由 Tejun Heo 提交于
cpu0 used special percpu area reserved by the linker, __cpu0_per_cpu, which is set up early in boot by head.S. However, this doesn't guarantee that the area will be on the same node as cpu0 and the percpu area for cpu0 ends up very far away from percpu areas for other cpus which cause problems for congruent percpu allocator. This patch makes percpu area initialization allocate percpu area for cpu0 like any other cpus and copy it from __cpu0_per_cpu which now resides in the __init area. This means that for cpu0, percpu area is first setup at __cpu0_per_cpu early by head.S and then moved to an area in the linear mapping during memory initialization and it's not allowed to take a pointer to percpu variables between head.S and memory initialization. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NTony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: linux-ia64 <linux-ia64@vger.kernel.org>
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由 Tejun Heo 提交于
All information necessary to initialize cpu possible and present maps are available once early_acpi_boot_init() is complete. Reorganize setup_arch() and acpi init functions such that, * CPU information is printed after LAPIC entries are parsed in early_acpi_boot_init(). * smp_build_cpu_map() is called by setup_arch() instead of acpi functions. * smp_build_cpu_map() is called once all CPU related information is available before memory is initialized. This is primarily to allow find_memory() to use cpu maps but is also a general cleanup. Please note that with this change, the somewhat ad-hoc early_cpu_possible_map defined and used for NUMA configurations is probably unnecessary. Something to clean up another day. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NTony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: linux-ia64 <linux-ia64@vger.kernel.org>
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由 Tejun Heo 提交于
If CONFIG_VIRTUAL_MEM_MAP is enabled, ia64 defines macro VMALLOC_END as unsigned long variable vmalloc_end which is adjusted to prepare room for vmemmap. This becomes probnlematic if a local variables vmalloc_end is defined in some function (not very unlikely) and VMALLOC_END is used in the function - the function thinks its referencing the global VMALLOC_END value but would be referencing its own local vmalloc_end variable. There's no reason VMALLOC_END should be a macro. Just define it as an unsigned long variable if CONFIG_VIRTUAL_MEM_MAP is set to avoid nasty surprises. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NTony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: linux-ia64 <linux-ia64@vger.kernel.org> Cc: Christoph Lameter <cl@linux-foundation.org>
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- 28 9月, 2009 1 次提交
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由 Alexey Dobriyan 提交于
* mark struct vm_area_struct::vm_ops as const * mark vm_ops in AGP code But leave TTM code alone, something is fishy there with global vm_ops being used. Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 27 9月, 2009 1 次提交
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由 Len Brown 提交于
ia64's sim_defconfig uses CONFIG_ACPI=n which now #define's acpi_disabled in <linux/acpi.h> So we shouldn't re-define it here in <asm/acpi.h> Signed-off-by: NLen Brown <len.brown@intel.com>
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- 25 9月, 2009 1 次提交
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由 Tony Luck 提交于
Back in January 2008 Nick Piggin implemented "ticket" spinlocks for X86 (See commit 314cdbef). IA64 implementation has a couple of differences because of the available atomic operations ... e.g. we have no fetchadd2 instruction that operates on a 16-bit quantity so we make ticket locks use a 32-bit word for each of the current ticket and now-serving values. Performance on uncontended locks is about 8% worse than the previous implementation, but this seems a good trade for determinism in the contended case. Performance impact on macro-level benchmarks is in the noise. Signed-off-by: NTony Luck <tony.luck@intel.com>
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- 24 9月, 2009 4 次提交
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由 Rusty Russell 提交于
Now everyone is converted to arch_send_call_function_ipi_mask, remove the shim and the #defines. Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
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由 Rusty Russell 提交于
There were replaced by topology_core_cpumask and topology_thread_cpumask. Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
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由 Rusty Russell 提交于
smp_call_function_many is the new version: it takes a pointer. Also, use mm accessor macro while we're changing this. Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
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由 Rusty Russell 提交于
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
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- 23 9月, 2009 4 次提交
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由 KAMEZAWA Hiroyuki 提交于
For /proc/kcore, each arch registers its memory range by kclist_add(). In usual, - range of physical memory - range of vmalloc area - text, etc... are registered but "range of physical memory" has some troubles. It doesn't updated at memory hotplug and it tend to include unnecessary memory holes. Now, /proc/iomem (kernel/resource.c) includes required physical memory range information and it's properly updated at memory hotplug. Then, it's good to avoid using its own code(duplicating information) and to rebuild kclist for physical memory based on /proc/iomem. Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: NJiri Slaby <jirislaby@gmail.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: WANG Cong <xiyou.wangcong@gmail.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 KAMEZAWA Hiroyuki 提交于
Some 64bit arch has special segment for mapping kernel text. It should be entried to /proc/kcore in addtion to direct-linear-map, vmalloc area. This patch unifies KCORE_TEXT entry scattered under x86 and ia64. I'm not familiar with other archs (mips has its own even after this patch) but range of [_stext ..._end) is a valid area of text and it's not in direct-map area, defining CONFIG_ARCH_PROC_KCORE_TEXT is only a necessary thing to do. Note: I left mips as it is now. Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 KAMEZAWA Hiroyuki 提交于
For /proc/kcore, vmalloc areas are registered per arch. But, all of them registers same range of [VMALLOC_START...VMALLOC_END) This patch unifies them. By this. archs which have no kclist_add() hooks can see vmalloc area correctly. Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 KAMEZAWA Hiroyuki 提交于
Presently, kclist_add() only eats start address and size as its arguments. Considering to make kclist dynamically reconfigulable, it's necessary to know which kclists are for System RAM and which are not. This patch add kclist types as KCORE_RAM KCORE_VMALLOC KCORE_TEXT KCORE_OTHER This "type" is used in a patch following this for detecting KCORE_RAM. Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 22 9月, 2009 3 次提交
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由 Arnd Bergmann 提交于
A number of architectures have identical asm/mman.h files so they can all be merged by using the new generic file. The remaining asm/mman.h files are substantially different from each other. Signed-off-by: NArnd Bergmann <arnd@arndb.de> Cc: <linux-arch@vger.kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Arnd Bergmann 提交于
Add a flag for mmap that will be used to request a huge page region that will look like anonymous memory to user space. This is accomplished by using a file on the internal vfsmount. MAP_HUGETLB is a modifier of MAP_ANONYMOUS and so must be specified with it. The region will behave the same as a MAP_ANONYMOUS region using small pages. The patch also adds the MAP_STACK flag, which was previously defined only on some architectures but not on others. Since MAP_STACK is meant to be a hint only, architectures can define it without assigning a specific meaning to it. Signed-off-by: NArnd Bergmann <arnd@arndb.de> Cc: Eric B Munson <ebmunson@us.ibm.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: David Rientjes <rientjes@google.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Geert Uytterhoeven 提交于
Commit 96177299 ("Drop free_pages()") modified nr_free_pages() to return 'unsigned long' instead of 'unsigned int'. This made the casts to 'unsigned long' in most callers superfluous, so remove them. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: NGeert Uytterhoeven <Geert.Uytterhoeven@sonycom.com> Reviewed-by: NChristoph Lameter <cl@linux-foundation.org> Acked-by: NIngo Molnar <mingo@elte.hu> Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk> Acked-by: NDavid S. Miller <davem@davemloft.net> Acked-by: NKyle McMartin <kyle@mcmartin.ca> Acked-by: NWANG Cong <xiyou.wangcong@gmail.com> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Haavard Skinnemoen <hskinnemoen@atmel.com> Cc: Mikael Starvik <starvik@axis.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Hirokazu Takata <takata@linux-m32r.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: David Howells <dhowells@redhat.com> Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Chris Zankel <zankel@tensilica.com> Cc: Michal Simek <monstr@monstr.eu> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 21 9月, 2009 2 次提交
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由 Anand Gadiyar 提交于
Signed-off-by: NAnand Gadiyar <gadiyar@ti.com> Signed-off-by: NJiri Kosina <jkosina@suse.cz>
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由 Joe Perches 提交于
Signed-off-by: NJoe Perches <joe@perches.com> Signed-off-by: NTim Abbott <tabbott@ksplice.com> Acked-by: NPaul Mundt <lethal@linux-sh.org> Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
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- 20 9月, 2009 2 次提交
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由 Sam Ravnborg 提交于
ld-option is misnamed as it test options to gcc, not to ld. Renamed it to reflect this. Cc: Andi Kleen <andi@firstfloor.org> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
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由 Sam Ravnborg 提交于
Replace the use of CROSS_COMPILE to select a customized installkernel script with the possibility to set INSTALLKERNEL to select a custom installkernel script when running make: make INSTALLKERNEL=arm-installkernel install With this patch we are now more consistent across different architectures - they did not all support use of CROSS_COMPILE. The use of CROSS_COMPILE was a hack as this really belongs to gcc/binutils and the installkernel script does not change just because we change toolchain. The use of CROSS_COMPILE caused troubles with an upcoming patch that saves CROSS_COMPILE when a kernel is built - it would no longer be installable. [Thanks to Peter Z. for this hint] This patch undos what Ian did in commit: 0f8e2d62 ("use ${CROSS_COMPILE}installkernel in arch/*/boot/install.sh") The patch has been lightly tested on x86 only - but all changes looks obvious. Acked-by: NPeter Zijlstra <peterz@infradead.org> Acked-by: Mike Frysinger <vapier@gentoo.org> [blackfin] Acked-by: Russell King <linux@arm.linux.org.uk> [arm] Acked-by: Paul Mundt <lethal@linux-sh.org> [sh] Acked-by: "H. Peter Anvin" <hpa@zytor.com> [x86] Cc: Ian Campbell <icampbell@arcom.com> Cc: Tony Luck <tony.luck@intel.com> [ia64] Cc: Fenghua Yu <fenghua.yu@intel.com> [ia64] Cc: Hirokazu Takata <takata@linux-m32r.org> [m32r] Cc: Geert Uytterhoeven <geert@linux-m68k.org> [m68k] Cc: Kyle McMartin <kyle@mcmartin.ca> [parisc] Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> [powerpc] Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> [s390] Cc: Thomas Gleixner <tglx@linutronix.de> [x86] Cc: Ingo Molnar <mingo@redhat.com> [x86] Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
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- 17 9月, 2009 1 次提交
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由 Anirban Sinha 提交于
The "cleanup console_print()" patch in commit 353f6dd2 introduced an "extern" declaration into an assembly language file. Remove it. Signed-off-by: NAnirban Sinha <asinha@zeugmasystems.com> Signed-off-by: NTony Luck <tony.luck@intel.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 16 9月, 2009 4 次提交
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由 Peter Zijlstra 提交于
Sysbench thinks SD_BALANCE_WAKE is too agressive and kbuild doesn't really mind too much, SD_BALANCE_NEWIDLE picks up most of the slack. On a dual socket, quad core, dual thread nehalem system: sysbench (--num_threads=16): SD_BALANCE_WAKE-: 13982 tx/s SD_BALANCE_WAKE+: 15688 tx/s kbuild (-j16): SD_BALANCE_WAKE-: 47.648295846 seconds time elapsed ( +- 0.312% ) SD_BALANCE_WAKE+: 47.608607360 seconds time elapsed ( +- 0.026% ) (same within noise) Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Nelson Elhage 提交于
Aside from using fewer output sections and moving some data around, the main side effect of this change is changing the alignment of some sections. In particular: * cachline-aligned and read_mostly data are now aligned to SMP_CACHE_BYTES. (Previously, they were laid out consecutively after a PAGE_SIZE alignment) * .init.ramfs is now page-aligned, per the INIT_RAM_FS macro. (Previously it had no explicit alignment). Signed-off-by: NNelson Elhage <nelhage@ksplice.com> Signed-off-by: NTony Luck <tony.luck@intel.com>
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由 Nelson Elhage 提交于
Signed-off-by: NNelson Elhage <nelhage@ksplice.com> Signed-off-by: NTony Luck <tony.luck@intel.com>
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由 Tim Abbott 提交于
It seems that start_ap doesn't need to be in a special location in the kernel, but it references some init code so it should be in .ref.text. Since this is the only thing in the .text.head section, eliminate .text.head from the linker script. Signed-off-by: NTim Abbott <tabbott@ksplice.com> Signed-off-by: NTony Luck <tony.luck@intel.com>
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- 15 9月, 2009 12 次提交
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由 Jiri Slaby 提交于
When * there is almost out of ates * one asks for more than one ate * there are some available at the end of ate array then the inner for loop will end without incrementing 'index'. This means the outer loop will start at the same point finding it's available and runs the inner loop again from the same index. This repeats forever. Hence make sure we check we were at the end of ate array and return an error in such case. Signed-off-by: NJiri Slaby <jirislaby@gmail.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Found-by: NJeff Mahoney <jeffm@novell.com> Signed-off-by: NTony Luck <tony.luck@intel.com>
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由 Peter Zijlstra 提交于
If we're looking to place a new task, we might as well find the idlest position _now_, not 1 tick ago. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Mike Galbraith 提交于
Make the idle balancer more agressive, to improve a x264 encoding workload provided by Jason Garrett-Glaser: NEXT_BUDDY NO_LB_BIAS encoded 600 frames, 252.82 fps, 22096.60 kb/s encoded 600 frames, 250.69 fps, 22096.60 kb/s encoded 600 frames, 245.76 fps, 22096.60 kb/s NO_NEXT_BUDDY LB_BIAS encoded 600 frames, 344.44 fps, 22096.60 kb/s encoded 600 frames, 346.66 fps, 22096.60 kb/s encoded 600 frames, 352.59 fps, 22096.60 kb/s NO_NEXT_BUDDY NO_LB_BIAS encoded 600 frames, 425.75 fps, 22096.60 kb/s encoded 600 frames, 425.45 fps, 22096.60 kb/s encoded 600 frames, 422.49 fps, 22096.60 kb/s Peter pointed out that this is better done via newidle_idx, not via LB_BIAS, newidle balancing should look for where there is load _now_, not where there was load 2 ticks ago. Worst-case latencies are improved as well as no buddies means less vruntime spread. (as per prior lkml discussions) This change improves kbuild-peak parallelism as well. Reported-by: NJason Garrett-Glaser <darkshikari@gmail.com> Signed-off-by: NMike Galbraith <efault@gmx.de> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1253011667.9128.16.camel@marge.simson.net> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Peter Zijlstra 提交于
When merging select_task_rq_fair() and sched_balance_self() we lost the use of wake_idx, restore that and set them to 0 to make wake balancing more aggressive. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Peter Zijlstra 提交于
The problem with wake_idle() is that is doesn't respect things like cpu_power, which means it doesn't deal well with SMT nor the recent RT interaction. To cure this, it needs to do what sched_balance_self() does, which leads to the possibility of merging select_task_rq_fair() and sched_balance_self(). Modify sched_balance_self() to: - update_shares() when walking up the domain tree, (it only called it for the top domain, but it should have done this anyway), which allows us to remove this ugly bit from try_to_wake_up(). - do wake_affine() on the smallest domain that contains both this (the waking) and the prev (the wakee) cpu for WAKE invocations. Then use the top-down balance steps it had to replace wake_idle(). This leads to the dissapearance of SD_WAKE_BALANCE and SD_WAKE_IDLE_FAR, with SD_WAKE_IDLE replaced with SD_BALANCE_WAKE. SD_WAKE_AFFINE needs SD_BALANCE_WAKE to be effective. Touch all topology bits to replace the old with new SD flags -- platforms might need re-tuning, enabling SD_BALANCE_WAKE conditionally on a NUMA distance seems like a good additional feature, magny-core and small nehalem systems would want this enabled, systems with slow interconnects would not. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Anirban Sinha 提交于
console_print() is an old legacy interface mostly unused in the entire kernel tree. It's best to clean up its existing use and let developers use their own implementation of it as they feel fit. Signed-off-by: NAnirban Sinha <asinha@zeugmasystems.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Hidetoshi Seto 提交于
Setting monarch_cpu = -1 to let slaves frozen might not work, because there might be slaves being late, not entered the rendezvous yet. Such slaves might be caught in while (monarch_cpu == -1) loop. Use kdump_in_progress instead of monarch_cpus to break INIT rendezvous and let all slaves enter DIE_INIT_SLAVE_LEAVE smoothly. And monarch no longer need to manage rendezvous if once kdump_in_progress is set, catch the monarch in DIE_INIT_MONARCH_ENTER then. Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Haren Myneni <hbabu@us.ibm.com> Cc: kexec@lists.infradead.org Acked-by: NFenghua Yu <fenghua.yu@intel.com> Signed-off-by: NTony Luck <tony.luck@intel.com>
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由 Hidetoshi Seto 提交于
kdump_on_init CPUs should be frozen if possible, otherwise it might hinder kdump. So if there are CPUs not respond to IPI, try INIT to stop them. Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Haren Myneni <hbabu@us.ibm.com> Cc: kexec@lists.infradead.org Acked-by: NFenghua Yu <fenghua.yu@intel.com> Signed-off-by: NTony Luck <tony.luck@intel.com>
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由 Hidetoshi Seto 提交于
Summary: Asserting INIT might block kdump if the system is already going to start kdump via panic. Description: INIT can interrupt anywhere in panic path, so it can interrupt in middle of kdump kicked by panic. Therefore there is a race if kdump is kicked concurrently, via Panic and via INIT. INIT could fail to invoke kdump if the system is already going to start kdump via panic. It could not restart kdump from INIT handler if some of cpus are already playing dead with INIT masked. It also means that INIT could block kdump's progress if no monarch is entered in the INIT rendezvous. Panic+INIT is a rare, but possible situation since it can be assumed that the kernel or an internal agent decides to panic the unstable system while another external agent decides to send an INIT to the system at same time. How to reproduce: Assert INIT just after panic, before all other cpus have frozen Expected results: continue kdump invoked by panic, or restart kdump from INIT Actual results: might be hang, crashdump not retrieved Proposed Fix: This patch masks INIT first in panic path to take the initiative on kdump, and reuse atomic value kdump_in_progress to make sure there is only one initiator of kdump. All INITs asserted later should be used only for freezing all other cpus. This mask will be removed soon by rfi in relocate_kernel.S, before jump into kdump kernel, after all cpus are frozen and no-op INIT handler is registered. So if INIT was in the interval while it is masked, it will pend on the system and will received just after the rfi, and handled by the no-op handler. If there was a MCA event while psr.mc is 1, in theory the event will pend on the system and will received just after the rfi same as above. MCA handler is unregistered here at the time, so received MCA will not reach to OS_MCA and will result in warmboot by SAL. Note that codes in this masked interval are relatively simpler than that in MCA/INIT handler which also executed with the mask. So it can be said that probability of error in this interval is supposed not so higher than that in MCA/INIT handler. Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Haren Myneni <hbabu@us.ibm.com> Cc: kexec@lists.infradead.org Acked-by: NFenghua Yu <fenghua.yu@intel.com> Signed-off-by: NTony Luck <tony.luck@intel.com>
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由 Hidetoshi Seto 提交于
Summary: Asserting INIT on cpu going to be offline will result in unexpected behavior. It will be a real problem in kdump cases where INIT might be asserted to unstable APs going to be offline by returning to SAL. Description: Since psr.mc is cleared when bits in psr are set to SAL_PSR_BITS_TO_SET in ia64_jump_to_sal(), there is a small window (~few msecs) that the cpu can receive INIT even if the cpu enter there via INIT handler. In this window we do restore of registers for SAL, so INIT asserted here will not work properly. It is hard to remove this window by masking INIT (i.e. setting psr.mc) because we have to unmask it later in OS, because we have to use branch instruction (br.ret, not rfi) to return SAL, due to OS_BOOT_RENDEZ to SAL return convention. I suppose this window will not be a real problem on cpu offline if we can educate people not to push INIT button during hotplug operation. However, only exception is a race in kdump and INIT. Now kdump returns APs to SAL before processing dump, but the kernel might receive INIT at that point in time. Such INIT might be asserted by kdump itself if an AP doesn't react IPI soon and kdump decided to use INIT to stop the AP. Or it might be asserted by operator or an external agent to start dump on the unstable system. Such panic+INIT or INIT+INIT cases should be rare, but it will be happy if we can retrieve crashdump even in such cases. How to reproduce: panic+INIT or INIT+INIT, with kdump configured Expected results: crashdump is retrieved anyway Actual results: panic, hang etc. (unexpected) Proposed fix To avoid the window on the way to SAL, this patch stops returning APs to SAL in case of kdump. In other words, this patch makes APs spin in OS instead of spinning in SAL. (* Note: What impact would be there? If a cpu is spinning in SAL, the cpu is in BOOT_RENDEZ loop, as same as offlined cpu. In theory if an INIT is asserted there, cpus in the BOOT_RENDEZ loop should not invoke OS_INIT on it. So in either way, no matter where the cpu is spinning actually in, once cpu starts spin and act as "frozen," INIT on the cpu have no effects. From another point of view, all debug information on the cpu should have stored to memory before the cpu start to be frozen. So no more action on the cpu is required.) I confirmed that the kdump sometime hangs by concurrent INITs (another INIT after an INIT), and it doesn't hang after applying this patch. Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Haren Myneni <hbabu@us.ibm.com> Cc: kexec@lists.infradead.org Acked-by: NFenghua Yu <fenghua.yu@intel.com> Signed-off-by: NTony Luck <tony.luck@intel.com>
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由 Hidetoshi Seto 提交于
Summary: MCA on the beginning of kdump/kexec kernel will result in unexpected behavior because MCA handler for previous kernel is invoked on the kdump kernel. Description: Once a cpu is passed to new kernel, all resources in previous kernel should not be used from the cpu. Even the resources for MCA handler are no exception. So we cannot handle MCAs and its machine check errors during kernel transition, until new handler for new kernel is registered with new resources ready for handling the MCA. How to reproduce: Assert MCA while kdump kernel is booting, before new MCA handler for kdump kernel is registered. Expected(Desirable) results: No recovery, cancel kdump and reboot the system. Actual results: MCA handler for previous kernel is invoked on the kdump kernel. => panic, hang etc. (unexpected) Proposed fix: To avoid entering MCA handler from early stage of new kernel, unregister the entry point from SAL before leave from current kernel. Then SAL will make all MCAs to warmboot safely, without invoking OS_MCA. Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Haren Myneni <hbabu@us.ibm.com> Cc: kexec@lists.infradead.org Acked-by: NFenghua Yu <fenghua.yu@intel.com> Signed-off-by: NTony Luck <tony.luck@intel.com>
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由 Hidetoshi Seto 提交于
kdump/kexec kernel Summary: Asserting INIT on the beginning of kdump/kexec kernel will result in unexpected behavior because INIT handler for previous kernel is invoked on new kernel. Description: In panic situation, we can receive INIT while kernel transition, i.e. from beginning of panic to bootstrap of kdump kernel. Since we initialize registers on leave from current kernel, no longer monarch/slave handlers of current kernel in virtual mode are called safely. (In fact system goes hang as far as I confirmed) How to Reproduce: Start kdump # echo c > /proc/sysrq-trigger Then assert INIT while kdump kernel is booting, before new INIT handler for kdump kernel is registered. Expected(Desirable) result: kdump kernel boots without any problem, crashdump retrieved Actual result: INIT handler for previous kernel is invoked on kdump kernel => panic, hang etc. (unexpected) Proposed fix: We can unregister these init handlers from SAL before jumping into new kernel, however then the INIT will fallback to default behavior, result in warmboot by SAL (according to the SAL specification) and we cannot retrieve the crashdump. Therefore this patch introduces a NOP init handler and register it to SAL before leave from current kernel, to start kdump safely by preventing INITs from entering virtual mode and resulting in warmboot. On the other hand, in case of kexec that not for kdump, it also has same problem with INIT while kernel transition. This patch handles this case differently, because for kexec unregistering handlers will be preferred than registering NOP handler, since the situation "no handlers registered" is usual state for kernel's entry. Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Haren Myneni <hbabu@us.ibm.com> Cc: kexec@lists.infradead.org Acked-by: NFenghua Yu <fenghua.yu@intel.com> Signed-off-by: NTony Luck <tony.luck@intel.com>
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