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apic->apicid_to_node() is 32bit specific apic operation which
determines NUMA node for a CPU. Depending on the APIC
implementation, it can be easier to determine NUMA node from
either physical or logical apicid. Currently,
->apicid_to_node() takes @logical_apicid and calls
hard_smp_processor_id() if the physical apicid is needed.
This prevents NUMA mapping from being queried from a different
CPU, which in turn makes it impossible to initialize NUMA
mapping before SMP bringup.
This patch replaces apic->apicid_to_node() with
->x86_32_numa_cpu_node() which takes @cpu, from which both
logical and physical apicids can easily be determined. While at
it, drop duplicate implementations from bigsmp_32 and summit_32,
and use the default one.
Signed-off-by: Tejun Heo <[email protected]>
Reviewed-by: Pekka Enberg <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
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On x86_32, the mapping between cpu and logical apic ID differs
depending on the specific apic implementation in use. The
mapping is initialized while bringing up CPUs; however, this
makes early inits ignore memory topology.
Add a x86_32 specific apic->x86_32_early_logical_apicid() which
is called early during boot to query the mapping. The mapping
is later verified against the result of init_apic_ldr(). The
method is allowed to return BAD_APICID if it can't be determined
early.
noop variant which always returns BAD_APICID is implemented and
added to all x86_32 apic implementations.
Signed-off-by: Tejun Heo <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
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After the previous patch, apic->cpu_to_logical_apicid() is no
longer used. Kill it.
For apic types with custom cpu_to_logical_apicid() which is also
used for other purposes, remove the function and modify its
users to do the mapping directly.
#ifdef's on CONFIG_SMP in es7000_32 and summit_32 are ignored
during conversion as they are not used for UP kernels.
Signed-off-by: Tejun Heo <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
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Unlike x86_64, on x86_32, the mapping from cpu to logical apicid
may vary depending on apic in use. cpu_2_logical_apicid[] array
is used for this mapping. Replace it with early percpu variable
x86_cpu_to_logical_apicid to make it better aligned with other
mappings.
Signed-off-by: Tejun Heo <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
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Both functions are used only in 32bit. Put them inside
CONFIG_X86_32. This is to prepare for logical apicid handling
update.
- Cyrill Gorcunov spotted that I forgot to move declarations in
ipi.h under CONFIG_X86_32. Fixed.
Signed-off-by: Tejun Heo <[email protected]>
Reviewed-by: Pekka Enberg <[email protected]>
Reviewed-by: Cyrill Gorcunov <[email protected]>
Acked-by: Yinghai Lu <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
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Commit 56d91f13 (x86, acpi: Add MAX_LOCAL_APIC for 32bit) added
MAX_LOCAL_APIC for x86_32 but didn't replace MAX_APICID users
with it. Convert MAX_APICID users to MAX_LOCAL_APIC and drop
MAX_APICID.
Signed-off-by: Tejun Heo <[email protected]>
Reviewed-by: Pekka Enberg <[email protected]>
Acked-by: Yinghai Lu <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
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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()
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All architecture specific rwsem headers carry the same function
prototypes. Just x86 adds asmregparm, which is an empty define on all
other architectures. S390 has a stale rwsem_downgrade_write()
prototype.
Remove the duplicates and add the prototypes to linux/rwsem.h
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: David Howells <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Richard Henderson <[email protected]>
Acked-by: Tony Luck <[email protected]>
Acked-by: Heiko Carstens <[email protected]>
Cc: Paul Mundt <[email protected]>
Acked-by: David Miller <[email protected]>
Cc: Chris Zankel <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
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Instead of having the same implementation in each architecture, move
it to linux/rwsem.h and remove the duplicates. It's unlikely that an
arch will ever implement something different, but we can deal with
that when it happens.
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: David Howells <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Matt Turner <[email protected]>
Acked-by: Tony Luck <[email protected]>
Acked-by: Heiko Carstens <[email protected]>
Cc: Paul Mundt <[email protected]>
Acked-by: David Miller <[email protected]>
Cc: Chris Zankel <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
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The rwsem initializers and related macros and functions are mostly the
same. Some of them lack the lockdep initializer, but having it in
place does not matter for architectures which do not support lockdep.
powerpc, sparc, x86: No functional change
sh, s390: Removes the duplicate init_rwsem (inline and #define)
alpha, ia64, xtensa: Use the lockdep capable init function in
lib/rwsem.c which is just uninlining the init
function for the LOCKDEP=n case
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: David Howells <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Matt Turner <[email protected]>
Acked-by: Tony Luck <[email protected]>
Acked-by: Heiko Carstens <[email protected]>
Cc: Paul Mundt <[email protected]>
Acked-by: David Miller <[email protected]>
Cc: Chris Zankel <[email protected]>
LKML-Reference: <[email protected]>
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The difference between these declarations is the data type of the
count member and the lack of lockdep in some architectures/
long is equivivalent to signed long and the #ifdef guarded dep_map
member does not hurt anyone.
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: David Howells <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Matt Turner <[email protected]>
Acked-by: Tony Luck <[email protected]>
Acked-by: Heiko Carstens <[email protected]>
Cc: Paul Mundt <[email protected]>
Acked-by: David Miller <[email protected]>
Cc: Chris Zankel <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
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Remove the typedef which has no real reason to be there.
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: David Howells <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Matt Turner <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Paul Mundt <[email protected]>
Cc: David Miller <[email protected]>
Cc: Chris Zankel <[email protected]>
LKML-Reference: <[email protected]>
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All rwsem implementations include the same headers. Include them from
include/linux/rwsem.h
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: David Howells <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Matt Turner <[email protected]>
Acked-by: Tony Luck <[email protected]>
Acked-by: Heiko Carstens <[email protected]>
Cc: Paul Mundt <[email protected]>
Acked-by: David Miller <[email protected]>
Cc: Chris Zankel <[email protected]>
LKML-Reference: <[email protected]>
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cpu_info is already with per_cpu, We can take llc_shared_map out
of cpu_info, and declare it as per_cpu variable directly.
So later referencing could be simple and directly instead of
diving to find cpu_info at first.
Also could make smp_store_cpu_info() much simple to avoid to do
save and restore trick.
Signed-off-by: Yinghai Lu <[email protected]>
Cc: Hans Rosenfeld <[email protected]>
Cc: Alok N Kataria <[email protected]>
Cc: Stephen Hemminger <[email protected]>
Cc: Hans J. Koch <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Andreas Herrmann <[email protected]>
Cc: Robert Richter <[email protected]>
Cc: Suresh Siddha <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
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"Link Control" devices (NB function 4) will be used by L3 cache
partitioning on family 0x15.
Signed-off-by: Hans Rosenfeld <[email protected]>
Cc: <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
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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 <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Tejun Heo <[email protected]>
LKML-Reference: <1295973114.3588.312.camel@edumazet-laptop>
Signed-off-by: Ingo Molnar <[email protected]>
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Left-over from the x86 merge ...
Signed-off-by: Yinghai Lu <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
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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 <[email protected]>
Reported-by: werner <[email protected]>
Reported-by: Minchan Kim <[email protected]>
Tested-by: Minchan Kim <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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
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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 <[email protected]>
Cc: Xiaotian Feng <[email protected]>
Cc: Jason Baron <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Arjan van de Ven <[email protected]>
Cc: Siarhei Liakh <[email protected]>
Cc: Xuxian Jiang <[email protected]>
Cc: James Morris <[email protected]>
Cc: Rusty Russell <[email protected]>
Cc: Dave Jones <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Andrew Morton <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
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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 <[email protected]>
Cc: [email protected] # 37.x
Cc: H. Peter Anvin <[email protected]>
Cc: Arjan van de Ven <[email protected]>
Cc: Len Brown <[email protected]>
Cc: Venkatesh Pallipadi <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: H. Peter Anvin <[email protected]>
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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
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The implementation of the cache flushing interfaces on the x86
is identical with the default implementation in asm-generic.
Signed-off-by: Akinobu Mita <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: [email protected]
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
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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 <[email protected]>
Reviewed-by: Thomas Renninger <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Thomas Renninger <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
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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
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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
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Add pmd_modify() for use with mprotect() on huge pmds.
Signed-off-by: Johannes Weiner <[email protected]>
Signed-off-by: Andrea Arcangeli <[email protected]>
Reviewed-by: Rik van Riel <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Signed-off-by: Andrea Arcangeli <[email protected]>
Reviewed-by: Rik van Riel <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Acked-by: Rik van Riel <[email protected]>
Signed-off-by: Johannes Weiner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Add needed pmd mangling functions with symmetry with their pte
counterparts. pmdp_splitting_flush() is the only new addition on the pmd_
methods and it's needed to serialize the VM against split_huge_page. It
simply atomically sets the splitting bit in a similar way
pmdp_clear_flush_young atomically clears the accessed bit.
pmdp_splitting_flush() also has to flush the tlb to make it effective
against gup_fast, but it wouldn't really require to flush the tlb too.
Just the tlb flush is the simplest operation we can invoke to serialize
pmdp_splitting_flush() against gup_fast.
Signed-off-by: Andrea Arcangeli <[email protected]>
Acked-by: Rik van Riel <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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These returns 0 at compile time when the config option is disabled, to
allow gcc to eliminate the transparent hugepage function calls at compile
time without additional #ifdefs (only the export of those functions have
to be visible to gcc but they won't be required at link time and
huge_memory.o can be not built at all).
_PAGE_BIT_UNUSED1 is never used for pmd, only on pte.
Signed-off-by: Andrea Arcangeli <[email protected]>
Acked-by: Rik van Riel <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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No paravirt version of set_pmd_at/pmd_update/pmd_update_defer.
Signed-off-by: Andrea Arcangeli <[email protected]>
Acked-by: Rik van Riel <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Paravirt ops pmd_update/pmd_update_defer/pmd_set_at. Not all might be
necessary (vmware needs pmd_update, Xen needs set_pmd_at, nobody needs
pmd_update_defer), but this is to keep full simmetry with pte paravirt
ops, which looks cleaner and simpler from a common code POV.
Signed-off-by: Andrea Arcangeli <[email protected]>
Acked-by: Rik van Riel <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Used by paravirt and not paravirt set_pmd_at.
Signed-off-by: Andrea Arcangeli <[email protected]>
Acked-by: Rik van Riel <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-olpc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, olpc: Speed up device tree creation during boot
x86, olpc: Add OLPC device-tree support
x86, of: Define irq functions to allow drivers/of/* to build on x86
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* 'kvm-updates/2.6.38' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (142 commits)
KVM: Initialize fpu state in preemptible context
KVM: VMX: when entering real mode align segment base to 16 bytes
KVM: MMU: handle 'map_writable' in set_spte() function
KVM: MMU: audit: allow audit more guests at the same time
KVM: Fetch guest cr3 from hardware on demand
KVM: Replace reads of vcpu->arch.cr3 by an accessor
KVM: MMU: only write protect mappings at pagetable level
KVM: VMX: Correct asm constraint in vmcs_load()/vmcs_clear()
KVM: MMU: Initialize base_role for tdp mmus
KVM: VMX: Optimize atomic EFER load
KVM: VMX: Add definitions for more vm entry/exit control bits
KVM: SVM: copy instruction bytes from VMCB
KVM: SVM: implement enhanced INVLPG intercept
KVM: SVM: enhance mov DR intercept handler
KVM: SVM: enhance MOV CR intercept handler
KVM: SVM: add new SVM feature bit names
KVM: cleanup emulate_instruction
KVM: move complete_insn_gp() into x86.c
KVM: x86: fix CR8 handling
KVM guest: Fix kvm clock initialization when it's configured out
...
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git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (43 commits)
Documentation/trace/events.txt: Remove obsolete sched_signal_send.
writeback: fix global_dirty_limits comment runtime -> real-time
ppc: fix comment typo singal -> signal
drivers: fix comment typo diable -> disable.
m68k: fix comment typo diable -> disable.
wireless: comment typo fix diable -> disable.
media: comment typo fix diable -> disable.
remove doc for obsolete dynamic-printk kernel-parameter
remove extraneous 'is' from Documentation/iostats.txt
Fix spelling milisec -> ms in snd_ps3 module parameter description
Fix spelling mistakes in comments
Revert conflicting V4L changes
i7core_edac: fix typos in comments
mm/rmap.c: fix comment
sound, ca0106: Fix assignment to 'channel'.
hrtimer: fix a typo in comment
init/Kconfig: fix typo
anon_inodes: fix wrong function name in comment
fix comment typos concerning "consistent"
poll: fix a typo in comment
...
Fix up trivial conflicts in:
- drivers/net/wireless/iwlwifi/iwl-core.c (moved to iwl-legacy.c)
- fs/ext4/ext4.h
Also fix missed 'diabled' typo in drivers/net/bnx2x/bnx2x.h while at it.
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This integrates the XZ decompression code to the x86 pre-boot code.
mkpiggy.c is updated to reserve about 32 KiB more buffer safety margin for
kernel decompression. It is done unconditionally for all decompressors to
keep the code simpler.
The XZ decompressor needs around 30 KiB of heap, so the heap size is
increased to 32 KiB on both x86-32 and x86-64.
Documentation/x86/boot.txt is updated to list the XZ magic number.
With the x86 BCJ filter in XZ, XZ-compressed x86 kernel tends to be a few
percent smaller than the equivalent LZMA-compressed kernel.
Signed-off-by: Lasse Collin <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Alain Knaff <[email protected]>
Cc: Albin Tonnerre <[email protected]>
Cc: Phillip Lougher <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Drop the old geode_gpio crud, as well as the raw outl() calls; instead,
use the Linux GPIO API where possible, and the cs5535_gpio API in other
places.
Note that we don't actually clean up the driver properly yet (once loaded,
it always remains loaded). That'll come later..
This patch is necessary for building the driver.
Signed-off-by: Andres Salomon <[email protected]>
Cc: Greg KH <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Having four variables for the same thing:
idle_halt, idle_nomwait, force_mwait and boot_option_idle_overrides
is rather confusing and unnecessary complex.
if idle= boot param is passed, only set up one variable:
boot_option_idle_overrides
Introduces following functional changes/fixes:
- intel_idle driver does not register if any idle=xy
boot param is passed.
- processor_idle.c will also not register a cpuidle driver
and get active if idle=halt is passed.
Before a cpuidle driver with one (C1, halt) state got registered
Now the default_idle function will be used which finally uses
the same idle call to enter sleep state (safe_halt()), but
without registering a whole cpuidle driver.
That means idle= param will always avoid cpuidle drivers to register
with one exception (same behavior as before):
idle=nomwait
may still register acpi_idle cpuidle driver, but C1 will not use
mwait, but hlt. This can be a workaround for IO based deeper sleep
states where C1 mwait causes problems.
Signed-off-by: Thomas Renninger <[email protected]>
cc: [email protected]
Signed-off-by: Len Brown <[email protected]>
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It only allows to audit one guest in the system since:
- 'audit_point' is a glob variable
- mmu_audit_disable() is called in kvm_mmu_destroy(), so audit is disabled
after a guest exited
this patch fix those issues then allow to audit more guests at the same time
Signed-off-by: Xiao Guangrong <[email protected]>
Signed-off-by: Avi Kivity <[email protected]>
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Instead of syncing the guest cr3 every exit, which is expensince on vmx
with ept enabled, sync it only on demand.
[sheng: fix incorrect cr3 seen by Windows XP]
Signed-off-by: Sheng Yang <[email protected]>
Signed-off-by: Avi Kivity <[email protected]>
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Signed-off-by: Avi Kivity <[email protected]>
Signed-off-by: Marcelo Tosatti <[email protected]>
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In case of a nested page fault or an intercepted #PF newer SVM
implementations provide a copy of the faulting instruction bytes
in the VMCB.
Use these bytes to feed the instruction emulator and avoid the costly
guest instruction fetch in this case.
Signed-off-by: Andre Przywara <[email protected]>
Signed-off-by: Marcelo Tosatti <[email protected]>
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Newer SVM implementations provide the GPR number in the VMCB, so
that the emulation path is no longer necesarry to handle CR
register access intercepts. Implement the handling in svm.c and
use it when the info is provided.
Signed-off-by: Andre Przywara <[email protected]>
Signed-off-by: Marcelo Tosatti <[email protected]>
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emulate_instruction had many callers, but only one used all
parameters. One parameter was unused, another one is now
hidden by a wrapper function (required for a future addition
anyway), so most callers use now a shorter parameter list.
Signed-off-by: Andre Przywara <[email protected]>
Signed-off-by: Marcelo Tosatti <[email protected]>
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move the complete_insn_gp() helper function out of the VMX part
into the generic x86 part to make it usable by SVM.
Signed-off-by: Andre Przywara <[email protected]>
Signed-off-by: Marcelo Tosatti <[email protected]>
|