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2011-01-28Merge branch 'stable/bug-fixes-rc2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen * 'stable/bug-fixes-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen: xen/setup: Route halt operations to safe_halt pvop. xen/e820: Guard against E820_RAM not having page-aligned size or start. xen/p2m: Mark INVALID_P2M_ENTRY the mfn_list past max_pfn.
2011-01-27Merge branch 'x86-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: percpu, x86: Fix percpu_xchg_op() x86: Remove left over system_64.h x86-64: Don't use pointer to out-of-scope variable in dump_trace()
2011-01-27xen/setup: Route halt operations to safe_halt pvop.Stefano Stabellini
With this patch, the cpuidle driver does not load and does not issue the mwait operations. Instead the hypervisor is doing them (b/c we call the safe_halt pvops call). This fixes quite a lot of bootup issues wherein the user had to force interrupts for the continuation of the bootup. Details are discussed in: http://lists.xensource.com/archives/html/xen-devel/2011-01/msg00535.html [v2: Wrote the commit description] Reported-by: Daniel De Graaf <dgdegra@tycho.nsa.gov> Tested-by: Daniel De Graaf <dgdegra@tycho.nsa.gov> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-01-27xen/e820: Guard against E820_RAM not having page-aligned size or start.Stefano Stabellini
Under Dell Inspiron 1525, and Intel SandyBridge SDP's the BIOS e820 RAM is not page-aligned: [ 0.000000] Xen: 0000000000100000 - 00000000df66d800 (usable) We were not handling that and ended up setting up a pagetable that included up to df66e000 with the disastrous effect that when memset(NODE_DATA(nodeid), 0, sizeof(pg_data_t)); tried to clear the page it would crash at the 2K mark. Initially reported by Michael Young @ http://lists.xensource.com/archives/html/xen-devel/2011-01/msg00108.html The fix is to page-align the size and also take into consideration the start of the E820 (in case that is not page-aligned either). This fixes the bootup failure on those affected machines. This patch is a rework of the Micheal A Young initial patch and considers the case if the start is not page-aligned. Reported-by: Michael A Young <m.a.young@durham.ac.uk> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Michael A Young <m.a.young@durham.ac.uk>
2011-01-27xen/p2m: Mark INVALID_P2M_ENTRY the mfn_list past max_pfn.Stefan Bader
In case the mfn_list does not have enough entries to fill a p2m page we do not want the entries from max_pfn up to the boundary to be filled with unknown values. Hence set them to INVALID_P2M_ENTRY. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-01-26percpu, x86: Fix percpu_xchg_op()Eric Dumazet
These recent percpu commits: 2485b6464cf8: x86,percpu: Move out of place 64 bit ops into X86_64 section 8270137a0d50: cpuops: Use cmpxchg for xchg to avoid lock semantics Caused this 'perf top' crash: Kernel panic - not syncing: Fatal exception in interrupt Pid: 0, comm: swapper Tainted: G D 2.6.38-rc2-00181-gef71723 #413 Call Trace: <IRQ> [<ffffffff810465b5>] ? panic ? kmsg_dump ? kmsg_dump ? oops_end ? no_context ? __bad_area_nosemaphore ? perf_output_begin ? bad_area_nosemaphore ? do_page_fault ? __task_pid_nr_ns ? perf_event_tid ? __perf_event_header__init_id ? validate_chain ? perf_output_sample ? trace_hardirqs_off ? page_fault ? irq_work_run ? update_process_times ? tick_sched_timer ? tick_sched_timer ? __run_hrtimer ? hrtimer_interrupt ? account_system_vtime ? smp_apic_timer_interrupt ? apic_timer_interrupt ... Looking at assembly code, I found: list = this_cpu_xchg(irq_work_list, NULL); gives this wrong code : (gcc-4.1.2 cross compiler) ffffffff810bc45e: mov %gs:0xead0,%rax cmpxchg %rax,%gs:0xead0 jne ffffffff810bc45e <irq_work_run+0x3e> test %rax,%rax je ffffffff810bc4aa <irq_work_run+0x8a> Tell gcc we dirty eax/rax register in percpu_xchg_op() Compiler must use another register to store pxo_new__ We also dont need to reload percpu value after a jump, since a 'failed' cmpxchg already updated eax/rax Wrong generated code was : xor %rax,%rax /* load 0 into %rax */ 1: mov %gs:0xead0,%rax cmpxchg %rax,%gs:0xead0 jne 1b test %rax,%rax After patch : xor %rdx,%rdx /* load 0 into %rdx */ mov %gs:0xead0,%rax 1: cmpxchg %rdx,%gs:0xead0 jne 1b: test %rax,%rax Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Tejun Heo <tj@kernel.org> LKML-Reference: <1295973114.3588.312.camel@edumazet-laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-26x86: Remove left over system_64.hYinghai Lu
Left-over from the x86 merge ... Signed-off-by: Yinghai Lu <yinghai@kernel.org> LKML-Reference: <4D3E23D1.7010405@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-26thp: fix PARAVIRT x86 32bit noPAEAndrea Arcangeli
This fixes TRANSPARENT_HUGEPAGE=y with PARAVIRT=y and HIGHMEM64=n. The #ifdef that this patch removes was erratically introduced to fix a build error for noPAE (where pmd.pmd doesn't exist). So then the kernel built but it failed at runtime because set_pmd_at was a noop. This will correct it by enabling set_pmd_at for noPAE mode too. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: werner <w.landgraf@ru.ru> Reported-by: Minchan Kim <minchan.kim@gmail.com> Tested-by: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-24x86-64: Don't use pointer to out-of-scope variable in dump_trace()Jesper Juhl
In arch/x86/kernel/dumpstack_64.c::dump_trace() we have this code: ... if (!stack) { unsigned long dummy; stack = &dummy; if (task && task != current) stack = (unsigned long *)task->thread.sp; } bp = stack_frame(task, regs); /* * Print function call entries in all stacks, starting at the * current stack address. If the stacks consist of nested * exceptions */ tinfo = task_thread_info(task); for (;;) { char *id; unsigned long *estack_end; estack_end = in_exception_stack(cpu, (unsigned long)stack, &used, &id); ... You'll notice that we assign to 'stack' the address of the variable 'dummy' which is only in-scope inside the 'if (!stack)'. So when we later access stack (at the end of the above, and assuming we did not take the 'if (task && task != current)' branch) we'll be using the address of a variable that is no longer in scope. I believe this patch is the proper fix, but I freely admit that I'm not 100% certain. Signed-off-by: Jesper Juhl <jj@chaosbits.net> LKML-Reference: <alpine.LNX.2.00.1101242232590.10252@swampdragon.chaosbits.net> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2011-01-24Merge branch 'x86-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86: Fix jump label with RO/NX module protection crash x86, hotplug: Fix powersavings with offlined cores on AMD x86, mcheck, therm_throt.c: Export symbol platform_thermal_notify to allow coretemp to handler intr x86: Use asm-generic/cacheflush.h x86: Update CPU cache attributes table descriptors
2011-01-23x86: Fix jump label with RO/NX module protection crashmatthieu castet
If we use jump table in module init, there are marked as removed in __jump_table section after init is done. But we already applied ro permissions on the module, so we can't modify a read only section (crash in remove_jump_label_module_init). Make the __jump_table section rw. Signed-off-by: Matthieu CASTET <castet.matthieu@free.fr> Cc: Xiaotian Feng <xtfeng@gmail.com> Cc: Jason Baron <jbaron@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Siarhei Liakh <sliakh.lkml@gmail.com> Cc: Xuxian Jiang <jiang@cs.ncsu.edu> Cc: James Morris <jmorris@namei.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Dave Jones <davej@redhat.com> Cc: Kees Cook <kees.cook@canonical.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <4D3C3F20.7030203@free.fr> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-22x86, hotplug: Fix powersavings with offlined cores on AMDBorislav Petkov
ea53069231f9317062910d6e772cca4ce93de8c8 made a CPU use monitor/mwait when offline. This is not the optimal choice for AMD wrt to powersavings and we'd prefer our cores to halt (i.e. enter C1) instead. For this, the same selection whether to use monitor/mwait has to be used as when we select the idle routine for the machine. With this patch, offlining cores 1-5 on a X6 machine allows core0 to boost again. [ hpa: putting this in urgent since it is a (power) regression fix ] Reported-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: stable@kernel.org # 37.x Cc: H. Peter Anvin <hpa@linux.intel.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Len Brown <lenb@kernel.org> Cc: Venkatesh Pallipadi <venki@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.hl> Signed-off-by: Borislav Petkov <borislav.petkov@amd.com> LKML-Reference: <1295534572-10730-1-git-send-email-bp@amd64.org> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2011-01-21Merge branch 'fixes-2.6.38' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu * 'fixes-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: x86,percpu: Move out of place 64 bit ops into X86_64 section
2011-01-21Merge branch 'stable/bug-fixes-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen * 'stable/bug-fixes-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen: xen: p2m: correctly initialize partial p2m leaf xen: fix non-ANSI function warning in irq.c
2011-01-21xen: p2m: correctly initialize partial p2m leafStefan Bader
After changing the p2m mapping to a tree by commit 58e05027b530ff081ecea68e38de8d59db8f87e0 xen: convert p2m to a 3 level tree and trying to boot a DomU with 615MB of memory, the following crash was observed in the dump: kernel direct mapping tables up to 26f00000 @ 1ec4000-1fff000 BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<c0107397>] xen_set_pte+0x27/0x60 *pdpt = 0000000000000000 *pde = 0000000000000000 Adding further debug statements showed that when trying to set up pfn=0x26700 the returned mapping was invalid. pfn=0x266ff calling set_pte(0xc1fe77f8, 0x6b3003) pfn=0x26700 calling set_pte(0xc1fe7800, 0x3) Although the last_pfn obtained from the startup info is 0x26700, which should in turn not be hit, the additional 8MB which are added as extra memory normally seem to be ok. This lead to looking into the initial p2m tree construction, which uses the smaller value and assuming that there is other code handling the extra memory. When the p2m tree is set up, the leaves are directly pointed to the array which the domain builder set up. But if the mapping is not on a boundary that fits into one p2m page, this will result in the last leaf being only partially valid. And as the invalid entries are not initialized in that case, things go badly wrong. I am trying to fix that by checking whether the current leaf is a complete map and if not, allocate a completely new page and copy only the valid pointers there. This may not be the most efficient or elegant solution, but at least it seems to allow me booting DomUs with memory assignments all over the range. BugLink: http://bugs.launchpad.net/bugs/686692 [v2: Redid a bit of commit wording and fixed a compile warning] Signed-off-by: Stefan Bader <stefan.bader@canonical.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-01-21x86, mcheck, therm_throt.c: Export symbol platform_thermal_notify to allow ↵Fenghua Yu
coretemp to handler intr In therm_throt.c, commit 9e76a97efd31a08cb19d0ba12013b8fb4ad3e474 patch doesn't export the symbol platform_thermal_notify. Other drivers (e.g. drivers/hwmon/coretemp.c) can not find the symbol platform_thermal_notify when defining threshould interrupt handler. Please apply this patch to allow threshold interrupt handler in coretemp. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Cc: R Durgadoss <durgadoss.r@intel.com> Cc: khali@linux-fr.org <khali@linux-fr.org> Cc: lm-sensors@lm-sensors.org <lm-sensors@lm-sensors.org> Cc: Guenter Roeck <guenter.roeck@ericsson.com> LKML-Reference: <20110121041239.GB26954@linux-os.sc.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-21x86: Use asm-generic/cacheflush.hAkinobu Mita
The implementation of the cache flushing interfaces on the x86 is identical with the default implementation in asm-generic. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: arnd@arndb.de LKML-Reference: <1295523136-4277-2-git-send-email-akinobu.mita@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-21Merge branch 'core-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: smp: Allow on_each_cpu() to be called while early_boot_irqs_disabled status to init/main.c lockdep: Move early boot local IRQ enable/disable status to init/main.c
2011-01-21Merge branch 'akpm'Linus Torvalds
* akpm: kernel/smp.c: consolidate writes in smp_call_function_interrupt() kernel/smp.c: fix smp_call_function_many() SMP race memcg: correctly order reading PCG_USED and pc->mem_cgroup backlight: fix 88pm860x_bl macro collision drivers/leds/ledtrig-gpio.c: make output match input, tighten input checking MAINTAINERS: update Atmel AT91 entry mm: fix truncate_setsize() comment memcg: fix rmdir, force_empty with THP memcg: fix LRU accounting with THP memcg: fix USED bit handling at uncharge in THP memcg: modify accounting function for supporting THP better fs/direct-io.c: don't try to allocate more than BIO_MAX_PAGES in a bio mm: compaction: prevent division-by-zero during user-requested compaction mm/vmscan.c: remove duplicate include of compaction.h memblock: fix memblock_is_region_memory() thp: keep highpte mapped until it is no longer needed kconfig: rename CONFIG_EMBEDDED to CONFIG_EXPERT
2011-01-21kconfig: rename CONFIG_EMBEDDED to CONFIG_EXPERTDavid Rientjes
The meaning of CONFIG_EMBEDDED has long since been obsoleted; the option is used to configure any non-standard kernel with a much larger scope than only small devices. This patch renames the option to CONFIG_EXPERT in init/Kconfig and fixes references to the option throughout the kernel. A new CONFIG_EMBEDDED option is added that automatically selects CONFIG_EXPERT when enabled and can be used in the future to isolate options that should only be considered for embedded systems (RISC architectures, SLOB, etc). Calling the option "EXPERT" more accurately represents its intention: only expert users who understand the impact of the configuration changes they are making should enable it. Reviewed-by: Ingo Molnar <mingo@elte.hu> Acked-by: David Woodhouse <david.woodhouse@intel.com> Signed-off-by: David Rientjes <rientjes@google.com> Cc: Greg KH <gregkh@suse.de> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jens Axboe <axboe@kernel.dk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Robin Holt <holt@sgi.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-21Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linusLinus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus: virtio: remove virtio-pci root device LGUEST_GUEST: fix unmet direct dependencies (VIRTUALIZATION && VIRTIO) lguest: compile fixes lguest: Use this_cpu_ops lguest: document --rng in example Launcher lguest: example launcher to use guard pages, drop PROT_EXEC, fix limit logic lguest: --username and --chroot options
2011-01-20xen: fix non-ANSI function warning in irq.cRandy Dunlap
Fix sparse warning for non-ANSI function declaration: arch/x86/xen/irq.c:129:30: warning: non-ANSI function declaration of function 'xen_init_irq_ops' Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-01-20lockdep: Move early boot local IRQ enable/disable status to init/main.cTejun Heo
During early boot, local IRQ is disabled until IRQ subsystem is properly initialized. During this time, no one should enable local IRQ and some operations which usually are not allowed with IRQ disabled, e.g. operations which might sleep or require communications with other processors, are allowed. lockdep tracked this with early_boot_irqs_off/on() callbacks. As other subsystems need this information too, move it to init/main.c and make it generally available. While at it, toggle the boolean to early_boot_irqs_disabled instead of enabled so that it can be initialized with %false and %true indicates the exceptional condition. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> LKML-Reference: <20110120110635.GB6036@htj.dyndns.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-20x86: Update CPU cache attributes table descriptorsDave Jones
Update to latest definitions in: http://www.intel.com/Assets/PDF/appnote/241618.pdf [ Note, this update of the doc has removed some old values which we have listed. I think until we have clarification that they were never used in production, they should be left there. ] Signed-off-by: Dave Jones <davej@redhat.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> LKML-Reference: <20110120012055.GA15985@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-20LGUEST_GUEST: fix unmet direct dependencies (VIRTUALIZATION && VIRTIO)Randy Dunlap
Honor the kconfig menu hierarchy to remove kconfig dependency warnings: VIRTIO and VIRTIO_RING are subordinate to VIRTUALIZATION. warning: (LGUEST_GUEST) selects VIRTIO which has unmet direct dependencies (VIRTUALIZATION) warning: (LGUEST_GUEST && VIRTIO_PCI && VIRTIO_BALLOON) selects VIRTIO_RING which has unmet direct dependencies (VIRTUALIZATION && VIRTIO) Reported-by: Toralf F_rster <toralf.foerster@gmx.de> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-01-20lguest: compile fixesRusty Russell
arch/x86/lguest/boot.c: In function ‘lguest_init_IRQ’: arch/x86/lguest/boot.c:824: error: macro "__this_cpu_write" requires 2 arguments, but only 1 given arch/x86/lguest/boot.c:824: error: ‘__this_cpu_write’ undeclared (first use in this function) arch/x86/lguest/boot.c:824: error: (Each undeclared identifier is reported only once arch/x86/lguest/boot.c:824: error: for each function it appears in.) drivers/lguest/x86/core.c: In function ‘copy_in_guest_info’: drivers/lguest/x86/core.c:94: error: lvalue required as left operand of assignment Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-01-20lguest: Use this_cpu_opsChristoph Lameter
Use this_cpu_ops in a couple of places in lguest. Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-01-19x86: Unify "numa=" command line option handlingJan Beulich
In order to be able to suppress the use of SRAT tables that 32-bit Linux can't deal with (in one case known to lead to a non-bootable system, unless disabling ACPI altogether), move the "numa=" option handling to common code. Signed-off-by: Jan Beulich <jbeulich@novell.com> Reviewed-by: Thomas Renninger <trenn@suse.de> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Renninger <trenn@suse.de> LKML-Reference: <4D36B581020000780002D0FF@vpn.id2.novell.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-19Revert "x86: Make relocatable kernel work with new binutils"Ingo Molnar
This reverts commit 86b1e8dd83cb ("x86: Make relocatable kernel work with new binutils"). Markus Trippelsdorf reported a boot failure caused by this patch. The real solution to the original patch will likely involve an arch-generic solution to define an overlaid jiffies_64 and jiffies variables. Until that's done and tested on all architectures revert this commit to solve the regression. Reported-and-bisected-by: Markus Trippelsdorf <markus@trippelsdorf.de> Acked-by: "H. Peter Anvin" <hpa@zytor.com> Cc: Shaohua Li <shaohua.li@intel.com> Cc: "Lu, Hongjiu" <hongjiu.lu@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org>, Cc: Sam Ravnborg <sam@ravnborg.org> LKML-Reference: <4D36A759.60704@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-18Merge branch 'x86-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86: Clear irqstack thread_info x86: Make relocatable kernel work with new binutils
2011-01-18x86: Clear irqstack thread_infoBrian Gerst
Mathias Merz reported that v2.6.37 failed to boot on his system. Make sure that the thread_info part of the irqstack is initialized to zeroes. Reported-and-Tested-by: Matthias Merz <linux@merz-ka.de> Signed-off-by: Brian Gerst <brgerst@gmail.com> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> LKML-Reference: <AANLkTimyKXfJ1x8tgwrr1hYnNLrPfgE1NTe4z7L6tUDm@mail.gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-18x86: Make relocatable kernel work with new binutilsShaohua Li
The CONFIG_RELOCATABLE=y option is broken with new binutils, which will make boot panic. According to Lu Hongjiu, the affected binutils are from 2.20.51.0.12 to 2.21.51.0.3, which are release since Oct 22 this year. At least ubuntu 10.10 is using such binutils. See: http://sourceware.org/bugzilla/show_bug.cgi?id=12327 The reason of the boot panic is that we have 'jiffies = jiffies_64;' in vmlinux.lds.S. The jiffies isn't in any section. In kernel build, there is warning saying jiffies is an absolute address and can't be relocatable. At runtime, jiffies will have virtual address 0. Signed-off-by: Shaohua Li<shaohua.li@intel.com> Cc: Lu Hongjiu<hongjiu.lu@intel.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Sam Ravnborg <sam@ravnborg.org> LKML-Reference: <1295312269.1949.725.camel@sli10-conroe> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-15Merge branches 'core-fixes-for-linus', 'x86-fixes-for-linus', ↵Linus Torvalds
'timers-fixes-for-linus' and 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: rcu: avoid pointless blocked-task warnings rcu: demote SRCU_SYNCHRONIZE_DELAY from kernel-parameter status rtmutex: Fix comment about why new_owner can be NULL in wake_futex_pi() * 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, olpc: Add missing Kconfig dependencies x86, mrst: Set correct APB timer IRQ affinity for secondary cpu x86: tsc: Fix calibration refinement conditionals to avoid divide by zero x86, ia64, acpi: Clean up x86-ism in drivers/acpi/numa.c * 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: timekeeping: Make local variables static time: Rename misnamed minsec argument of clocks_calc_mult_shift() * 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: tracing: Remove syscall_exit_fields tracing: Only process module tracepoints once perf record: Add "nodelay" mode, disabled by default perf sched: Fix list of events, dropping unsupported ':r' modifier Revert "perf tools: Emit clearer message for sys_perf_event_open ENOENT return" perf top: Fix annotate segv perf evsel: Fix order of event list deletion
2011-01-15xen: export arbitrary_virt_to_machineStephen Rothwell
Fixes this build error: ERROR: "arbitrary_virt_to_machine" [drivers/xen/xen-gntdev.ko] undefined! Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-14x86, olpc: Add missing Kconfig dependenciesH. Peter Anvin
OLPC uses select for OLPC_OPENFIRMWARE, which means OLPC has to enforce the dependencies for OLPC_OPENFIRMWARE. Make sure it does so. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Cc: Daniel Drake <dsd@laptop.org> Cc: Andres Salomon <dilinger@queued.net> Cc: Grant Likely <grant.likely@secretlab.ca> LKML-Reference: <20100923162846.D8D409D401B@zog.reactivated.net> Cc: <stable@kernel.org> 2.6.37
2011-01-14x86, mrst: Set correct APB timer IRQ affinity for secondary cpuJacob Pan
Offlining the secondary CPU causes the timer irq affinity to be set to CPU 0. When the secondary CPU is back online again, the wrong irq affinity will be used. This patch ensures secondary per CPU timer always has the correct IRQ affinity when enabled. Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> LKML-Reference: <1294963604-18111-1-git-send-email-jacob.jun.pan@linux.intel.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Cc: <stable@kernel.org> 2.6.37
2011-01-14Merge branch 'linux-next' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6 * 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6: PCI/PM: Report wakeup events before resuming devices PCI/PM: Use pm_wakeup_event() directly for reporting wakeup events PCI: sysfs: Update ROM to include default owner write access x86/PCI: make Broadcom CNB20LE driver EMBEDDED and EXPERIMENTAL x86/PCI: don't use native Broadcom CNB20LE driver when ACPI is available PCI/ACPI: Request _OSC control once for each root bridge (v3) PCI: enable pci=bfsort by default on future Dell systems PCI/PCIe: Clear Root PME Status bits early during system resume PCI: pci-stub: ignore zero-length id parameters x86/PCI: irq and pci_ids patch for Intel Patsburg PCI: Skip id checking if no id is passed PCI: fix __pci_device_probe kernel-doc warning PCI: make pci_restore_state return void PCI: Disable ASPM if BIOS asks us to PCI: Add mask bit definition for MSI-X table PCI: MSI: Move MSI-X entry definition to pci_regs.h Fix up trivial conflicts in drivers/net/{skge.c,sky2.c} that had in the meantime been converted to not use legacy PCI power management, and thus no longer use pci_restore_state() at all (and that caused trivial conflicts with the "make pci_restore_state return void" patch)
2011-01-14x86: tsc: Fix calibration refinement conditionals to avoid divide by zeroJohn Stultz
Konrad Wilk reported that the new delayed calibration crashes with a divide by zero on Xen. The reason is that Xen sets the pmtimer address, but reading from it returns 0xffffff. That results in the ref_start and ref_stop value being the same, so the delta is zero which causes the divide by zero later in the calculation. The conditional (!hpet && !ref_start && !ref_stop) which sanity checks the calibration reference values doesn't really make sense. If the refs are null, but hpet is on, we still want to break out. The div by zero would be possible to trigger by chance if both reads from the hardware provided the exact same value (due to hardware wrapping). So checking if both the ref values are the same should handle if we don't have hardware (both null) or if they are the same value (either by invalid hardware, or by chance), avoiding the div by zero issue. [ tglx: Applied the same fix to native_calibrate_tsc() where this check was copied from ] Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: John Stultz <johnstul@us.ibm.com> LKML-Reference: <1295024788-15619-1-git-send-email-johnstul@us.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-01-14x86/PCI: make Broadcom CNB20LE driver EMBEDDED and EXPERIMENTALBjorn Helgaas
This functionality is known to be incomplete, so discourage its use in general-purpose kernels. The only reason to use this driver is to support PCI hotplug on CNB20LE- based machines that don't have ACPI, and there are very few such systems. Reference: https://bugzilla.redhat.com/show_bug.cgi?id=665109 Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2011-01-14x86/PCI: don't use native Broadcom CNB20LE driver when ACPI is availableBjorn Helgaas
The broadcom_bus.c quirk was written (without benefit of documentation) to support PCI hotplug on an old system that doesn't have ACPI. As such, we should only use it when the system doesn't have ACPI. If the system does have ACPI and we need the host bridge description, we should get it from the ACPI _CRS method. On machines older than 2008, we currently ignore _CRS, but that doesn't mean we should use broadcom_bus.c. It means we should either (a) do what we've done in the past and assume everything in the PCI gap is routed to bus 0 (so hotplug may not work), or (b) arrange to use _CRS. This patch does (a). Reference: https://bugzilla.redhat.com/show_bug.cgi?id=665109 Acked-by: Ira W. Snyder <iws@ovro.caltech.edu> Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2011-01-14PCI: enable pci=bfsort by default on future Dell systemsNarendra_K@Dell.com
This patch enables pci=bfsort by default on future Dell systems. It reads SMBIOS type 0xB1 vendor specific record and sets pci=bfsort accordingly. Offset Name Length Value Description 04 Flags0 Word Varies Bits 9-10 - 10:9 = 00 Unknown - 10:9 = 01 Breadth First - 10:9 = 10 Depth First - 10:9 = 11 Reserved 1. Any time pci=bfsort has to be enabled on a system, we need to add the model number of the system to the white list. With this patch, that is not required. 2. Typically, model number has to be added to the white list when the system is under development. With this change, that is not required. Signed-off-by: Jordan Hargrave <jordan_hargrave@dell.com> Signed-off-by: Narendra K <narendra_k@dell.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2011-01-14x86: OLPC: convert olpc-xo1 driver from pci device to platform deviceAndres Salomon
The cs5535-mfd driver now takes care of the PCI BAR handling; this means the olpc-xo1 driver shouldn't be touching the PCI device at all. This patch uses both cs5535-acpi and cs5535-pms platform devices rather than a single platform device because the cs5535-mfd driver may be used by other CS5535 platform-specific drivers; OLPC doesn't get to dictate that ACPI and PMS will always be used together. Signed-off-by: Andres Salomon <dilinger@queued.net> Acked-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2011-01-14Merge branch 'release' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6 * 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6: (59 commits) ACPI / PM: Fix build problems for !CONFIG_ACPI related to NVS rework ACPI: fix resource check message ACPI / Battery: Update information on info notification and resume ACPI: Drop device flag wake_capable ACPI: Always check if _PRW is present before trying to evaluate it ACPI / PM: Check status of power resources under mutexes ACPI / PM: Rename acpi_power_off_device() ACPI / PM: Drop acpi_power_nocheck ACPI / PM: Drop acpi_bus_get_power() Platform / x86: Make fujitsu_laptop use acpi_bus_update_power() ACPI / Fan: Rework the handling of power resources ACPI / PM: Register power resource devices as soon as they are needed ACPI / PM: Register acpi_power_driver early ACPI / PM: Add function for updating device power state consistently ACPI / PM: Add function for device power state initialization ACPI / PM: Introduce __acpi_bus_get_power() ACPI / PM: Introduce function for refcounting device power resources ACPI / PM: Add functions for manipulating lists of power resources ACPI / PM: Prevent acpi_power_get_inferred_state() from making changes ACPICA: Update version to 20101209 ...
2011-01-14Merge branch 'idle-release' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6 * 'idle-release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-idle-2.6: cpuidle/x86/perf: fix power:cpu_idle double end events and throw cpu_idle events from the cpuidle layer intel_idle: open broadcast clock event cpuidle: CPUIDLE_FLAG_CHECK_BM is omap3_idle specific cpuidle: CPUIDLE_FLAG_TLB_FLUSHED is specific to intel_idle cpuidle: delete unused CPUIDLE_FLAG_SHALLOW, BALANCED, DEEP definitions SH, cpuidle: delete use of NOP CPUIDLE_FLAGS_SHALLOW cpuidle: delete NOP CPUIDLE_FLAG_POLL ACPI: processor_idle: delete use of NOP CPUIDLE_FLAGs cpuidle: Rename X86 specific idle poll state[0] from C0 to POLL ACPI, intel_idle: Cleanup idle= internal variables cpuidle: Make cpuidle_enable_device() call poll_idle_init() intel_idle: update Sandy Bridge core C-state residency targets
2011-01-14Merge branch 'stable/gntdev' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen * 'stable/gntdev' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen: xen/p2m: Fix module linking error. xen p2m: clear the old pte when adding a page to m2p_override xen gntdev: use gnttab_map_refs and gnttab_unmap_refs xen: introduce gnttab_map_refs and gnttab_unmap_refs xen p2m: transparently change the p2m mappings in the m2p override xen/gntdev: Fix circular locking dependency xen/gntdev: stop using "token" argument xen: gntdev: move use of GNTMAP_contains_pte next to the map_op xen: add m2p override mechanism xen: move p2m handling to separate file xen/gntdev: add VM_PFNMAP to vma xen/gntdev: allow usermode to map granted pages xen: define gnttab_set_map_op/unmap_op Fix up trivial conflict in drivers/xen/Kconfig
2011-01-14thp: mmu_notifier_test_youngAndrea Arcangeli
For GRU and EPT, we need gup-fast to set referenced bit too (this is why it's correct to return 0 when shadow_access_mask is zero, it requires gup-fast to set the referenced bit). qemu-kvm access already sets the young bit in the pte if it isn't zero-copy, if it's zero copy or a shadow paging EPT minor fault we relay on gup-fast to signal the page is in use... We also need to check the young bits on the secondary pagetables for NPT and not nested shadow mmu as the data may never get accessed again by the primary pte. Without this closer accuracy, we'd have to remove the heuristic that avoids collapsing hugepages in hugepage virtual regions that have not even a single subpage in use. ->test_young is full backwards compatible with GRU and other usages that don't have young bits in pagetables set by the hardware and that should nuke the secondary mmu mappings when ->clear_flush_young runs just like EPT does. Removing the heuristic that checks the young bit in khugepaged/collapse_huge_page completely isn't so bad either probably but I thought it was worth it and this makes it reliable. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-14thp: don't allow transparent hugepage support without PSEAndrea Arcangeli
Archs implementing Transparent Hugepage Support must implement a function called has_transparent_hugepage to be sure the virtual or physical CPU supports Transparent Hugepages. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-14thp: add pmd_modifyJohannes Weiner
Add pmd_modify() for use with mprotect() on huge pmds. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-14thp: add x86 32bit supportJohannes Weiner
Add support for transparent hugepages to x86 32bit. Share the same VM_ bitflag for VM_MAPPED_COPY. mm/nommu.c will never support transparent hugepages. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-14thp: transparent hugepage coreAndrea Arcangeli
Lately I've been working to make KVM use hugepages transparently without the usual restrictions of hugetlbfs. Some of the restrictions I'd like to see removed: 1) hugepages have to be swappable or the guest physical memory remains locked in RAM and can't be paged out to swap 2) if a hugepage allocation fails, regular pages should be allocated instead and mixed in the same vma without any failure and without userland noticing 3) if some task quits and more hugepages become available in the buddy, guest physical memory backed by regular pages should be relocated on hugepages automatically in regions under madvise(MADV_HUGEPAGE) (ideally event driven by waking up the kernel deamon if the order=HPAGE_PMD_SHIFT-PAGE_SHIFT list becomes not null) 4) avoidance of reservation and maximization of use of hugepages whenever possible. Reservation (needed to avoid runtime fatal faliures) may be ok for 1 machine with 1 database with 1 database cache with 1 database cache size known at boot time. It's definitely not feasible with a virtualization hypervisor usage like RHEV-H that runs an unknown number of virtual machines with an unknown size of each virtual machine with an unknown amount of pagecache that could be potentially useful in the host for guest not using O_DIRECT (aka cache=off). hugepages in the virtualization hypervisor (and also in the guest!) are much more important than in a regular host not using virtualization, becasue with NPT/EPT they decrease the tlb-miss cacheline accesses from 24 to 19 in case only the hypervisor uses transparent hugepages, and they decrease the tlb-miss cacheline accesses from 19 to 15 in case both the linux hypervisor and the linux guest both uses this patch (though the guest will limit the addition speedup to anonymous regions only for now...). Even more important is that the tlb miss handler is much slower on a NPT/EPT guest than for a regular shadow paging or no-virtualization scenario. So maximizing the amount of virtual memory cached by the TLB pays off significantly more with NPT/EPT than without (even if there would be no significant speedup in the tlb-miss runtime). The first (and more tedious) part of this work requires allowing the VM to handle anonymous hugepages mixed with regular pages transparently on regular anonymous vmas. This is what this patch tries to achieve in the least intrusive possible way. We want hugepages and hugetlb to be used in a way so that all applications can benefit without changes (as usual we leverage the KVM virtualization design: by improving the Linux VM at large, KVM gets the performance boost too). The most important design choice is: always fallback to 4k allocation if the hugepage allocation fails! This is the _very_ opposite of some large pagecache patches that failed with -EIO back then if a 64k (or similar) allocation failed... Second important decision (to reduce the impact of the feature on the existing pagetable handling code) is that at any time we can split an hugepage into 512 regular pages and it has to be done with an operation that can't fail. This way the reliability of the swapping isn't decreased (no need to allocate memory when we are short on memory to swap) and it's trivial to plug a split_huge_page* one-liner where needed without polluting the VM. Over time we can teach mprotect, mremap and friends to handle pmd_trans_huge natively without calling split_huge_page*. The fact it can't fail isn't just for swap: if split_huge_page would return -ENOMEM (instead of the current void) we'd need to rollback the mprotect from the middle of it (ideally including undoing the split_vma) which would be a big change and in the very wrong direction (it'd likely be simpler not to call split_huge_page at all and to teach mprotect and friends to handle hugepages instead of rolling them back from the middle). In short the very value of split_huge_page is that it can't fail. The collapsing and madvise(MADV_HUGEPAGE) part will remain separated and incremental and it'll just be an "harmless" addition later if this initial part is agreed upon. It also should be noted that locking-wise replacing regular pages with hugepages is going to be very easy if compared to what I'm doing below in split_huge_page, as it will only happen when page_count(page) matches page_mapcount(page) if we can take the PG_lock and mmap_sem in write mode. collapse_huge_page will be a "best effort" that (unlike split_huge_page) can fail at the minimal sign of trouble and we can try again later. collapse_huge_page will be similar to how KSM works and the madvise(MADV_HUGEPAGE) will work similar to madvise(MADV_MERGEABLE). The default I like is that transparent hugepages are used at page fault time. This can be changed with /sys/kernel/mm/transparent_hugepage/enabled. The control knob can be set to three values "always", "madvise", "never" which mean respectively that hugepages are always used, or only inside madvise(MADV_HUGEPAGE) regions, or never used. /sys/kernel/mm/transparent_hugepage/defrag instead controls if the hugepage allocation should defrag memory aggressively "always", only inside "madvise" regions, or "never". The pmd_trans_splitting/pmd_trans_huge locking is very solid. The put_page (from get_user_page users that can't use mmu notifier like O_DIRECT) that runs against a __split_huge_page_refcount instead was a pain to serialize in a way that would result always in a coherent page count for both tail and head. I think my locking solution with a compound_lock taken only after the page_first is valid and is still a PageHead should be safe but it surely needs review from SMP race point of view. In short there is no current existing way to serialize the O_DIRECT final put_page against split_huge_page_refcount so I had to invent a new one (O_DIRECT loses knowledge on the mapping status by the time gup_fast returns so...). And I didn't want to impact all gup/gup_fast users for now, maybe if we change the gup interface substantially we can avoid this locking, I admit I didn't think too much about it because changing the gup unpinning interface would be invasive. If we ignored O_DIRECT we could stick to the existing compound refcounting code, by simply adding a get_user_pages_fast_flags(foll_flags) where KVM (and any other mmu notifier user) would call it without FOLL_GET (and if FOLL_GET isn't set we'd just BUG_ON if nobody registered itself in the current task mmu notifier list yet). But O_DIRECT is fundamental for decent performance of virtualized I/O on fast storage so we can't avoid it to solve the race of put_page against split_huge_page_refcount to achieve a complete hugepage feature for KVM. Swap and oom works fine (well just like with regular pages ;). MMU notifier is handled transparently too, with the exception of the young bit on the pmd, that didn't have a range check but I think KVM will be fine because the whole point of hugepages is that EPT/NPT will also use a huge pmd when they notice gup returns pages with PageCompound set, so they won't care of a range and there's just the pmd young bit to check in that case. NOTE: in some cases if the L2 cache is small, this may slowdown and waste memory during COWs because 4M of memory are accessed in a single fault instead of 8k (the payoff is that after COW the program can run faster). So we might want to switch the copy_huge_page (and clear_huge_page too) to not temporal stores. I also extensively researched ways to avoid this cache trashing with a full prefault logic that would cow in 8k/16k/32k/64k up to 1M (I can send those patches that fully implemented prefault) but I concluded they're not worth it and they add an huge additional complexity and they remove all tlb benefits until the full hugepage has been faulted in, to save a little bit of memory and some cache during app startup, but they still don't improve substantially the cache-trashing during startup if the prefault happens in >4k chunks. One reason is that those 4k pte entries copied are still mapped on a perfectly cache-colored hugepage, so the trashing is the worst one can generate in those copies (cow of 4k page copies aren't so well colored so they trashes less, but again this results in software running faster after the page fault). Those prefault patches allowed things like a pte where post-cow pages were local 4k regular anon pages and the not-yet-cowed pte entries were pointing in the middle of some hugepage mapped read-only. If it doesn't payoff substantially with todays hardware it will payoff even less in the future with larger l2 caches, and the prefault logic would blot the VM a lot. If one is emebdded transparent_hugepage can be disabled during boot with sysfs or with the boot commandline parameter transparent_hugepage=0 (or transparent_hugepage=2 to restrict hugepages inside madvise regions) that will ensure not a single hugepage is allocated at boot time. It is simple enough to just disable transparent hugepage globally and let transparent hugepages be allocated selectively by applications in the MADV_HUGEPAGE region (both at page fault time, and if enabled with the collapse_huge_page too through the kernel daemon). This patch supports only hugepages mapped in the pmd, archs that have smaller hugepages will not fit in this patch alone. Also some archs like power have certain tlb limits that prevents mixing different page size in the same regions so they will not fit in this framework that requires "graceful fallback" to basic PAGE_SIZE in case of physical memory fragmentation. hugetlbfs remains a perfect fit for those because its software limits happen to match the hardware limits. hugetlbfs also remains a perfect fit for hugepage sizes like 1GByte that cannot be hoped to be found not fragmented after a certain system uptime and that would be very expensive to defragment with relocation, so requiring reservation. hugetlbfs is the "reservation way", the point of transparent hugepages is not to have any reservation at all and maximizing the use of cache and hugepages at all times automatically. Some performance result: vmx andrea # LD_PRELOAD=/usr/lib64/libhugetlbfs.so HUGETLB_MORECORE=yes HUGETLB_PATH=/mnt/huge/ ./largep ages3 memset page fault 1566023 memset tlb miss 453854 memset second tlb miss 453321 random access tlb miss 41635 random access second tlb miss 41658 vmx andrea # LD_PRELOAD=/usr/lib64/libhugetlbfs.so HUGETLB_MORECORE=yes HUGETLB_PATH=/mnt/huge/ ./largepages3 memset page fault 1566471 memset tlb miss 453375 memset second tlb miss 453320 random access tlb miss 41636 random access second tlb miss 41637 vmx andrea # ./largepages3 memset page fault 1566642 memset tlb miss 453417 memset second tlb miss 453313 random access tlb miss 41630 random access second tlb miss 41647 vmx andrea # ./largepages3 memset page fault 1566872 memset tlb miss 453418 memset second tlb miss 453315 random access tlb miss 41618 random access second tlb miss 41659 vmx andrea # echo 0 > /proc/sys/vm/transparent_hugepage vmx andrea # ./largepages3 memset page fault 2182476 memset tlb miss 460305 memset second tlb miss 460179 random access tlb miss 44483 random access second tlb miss 44186 vmx andrea # ./largepages3 memset page fault 2182791 memset tlb miss 460742 memset second tlb miss 459962 random access tlb miss 43981 random access second tlb miss 43988 ============ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/time.h> #define SIZE (3UL*1024*1024*1024) int main() { char *p = malloc(SIZE), *p2; struct timeval before, after; gettimeofday(&before, NULL); memset(p, 0, SIZE); gettimeofday(&after, NULL); printf("memset page fault %Lu\n", (after.tv_sec-before.tv_sec)*1000000UL + after.tv_usec-before.tv_usec); gettimeofday(&before, NULL); memset(p, 0, SIZE); gettimeofday(&after, NULL); printf("memset tlb miss %Lu\n", (after.tv_sec-before.tv_sec)*1000000UL + after.tv_usec-before.tv_usec); gettimeofday(&before, NULL); memset(p, 0, SIZE); gettimeofday(&after, NULL); printf("memset second tlb miss %Lu\n", (after.tv_sec-before.tv_sec)*1000000UL + after.tv_usec-before.tv_usec); gettimeofday(&before, NULL); for (p2 = p; p2 < p+SIZE; p2 += 4096) *p2 = 0; gettimeofday(&after, NULL); printf("random access tlb miss %Lu\n", (after.tv_sec-before.tv_sec)*1000000UL + after.tv_usec-before.tv_usec); gettimeofday(&before, NULL); for (p2 = p; p2 < p+SIZE; p2 += 4096) *p2 = 0; gettimeofday(&after, NULL); printf("random access second tlb miss %Lu\n", (after.tv_sec-before.tv_sec)*1000000UL + after.tv_usec-before.tv_usec); return 0; } ============ Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>