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* mm: send one IPI per CPU to TLB flush all entries after unmapping pagesMel Gorman2015-09-041-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | An IPI is sent to flush remote TLBs when a page is unmapped that was potentially accesssed by other CPUs. There are many circumstances where this happens but the obvious one is kswapd reclaiming pages belonging to a running process as kswapd and the task are likely running on separate CPUs. On small machines, this is not a significant problem but as machine gets larger with more cores and more memory, the cost of these IPIs can be high. This patch uses a simple structure that tracks CPUs that potentially have TLB entries for pages being unmapped. When the unmapping is complete, the full TLB is flushed on the assumption that a refill cost is lower than flushing individual entries. Architectures wishing to do this must give the following guarantee. If a clean page is unmapped and not immediately flushed, the architecture must guarantee that a write to that linear address from a CPU with a cached TLB entry will trap a page fault. This is essentially what the kernel already depends on but the window is much larger with this patch applied and is worth highlighting. The architecture should consider whether the cost of the full TLB flush is higher than sending an IPI to flush each individual entry. An additional architecture helper called flush_tlb_local is required. It's a trivial wrapper with some accounting in the x86 case. The impact of this patch depends on the workload as measuring any benefit requires both mapped pages co-located on the LRU and memory pressure. The case with the biggest impact is multiple processes reading mapped pages taken from the vm-scalability test suite. The test case uses NR_CPU readers of mapped files that consume 10*RAM. Linear mapped reader on a 4-node machine with 64G RAM and 48 CPUs 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 Ops lru-file-mmap-read-elapsed 159.62 ( 0.00%) 120.68 ( 24.40%) Ops lru-file-mmap-read-time_range 30.59 ( 0.00%) 2.80 ( 90.85%) Ops lru-file-mmap-read-time_stddv 6.70 ( 0.00%) 0.64 ( 90.38%) 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 User 581.00 611.43 System 5804.93 4111.76 Elapsed 161.03 122.12 This is showing that the readers completed 24.40% faster with 29% less system CPU time. From vmstats, it is known that the vanilla kernel was interrupted roughly 900K times per second during the steady phase of the test and the patched kernel was interrupts 180K times per second. The impact is lower on a single socket machine. 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 Ops lru-file-mmap-read-elapsed 25.33 ( 0.00%) 20.38 ( 19.54%) Ops lru-file-mmap-read-time_range 0.91 ( 0.00%) 1.44 (-58.24%) Ops lru-file-mmap-read-time_stddv 0.28 ( 0.00%) 0.47 (-65.34%) 4.2.0-rc1 4.2.0-rc1 vanilla flushfull-v7 User 58.09 57.64 System 111.82 76.56 Elapsed 27.29 22.55 It's still a noticeable improvement with vmstat showing interrupts went from roughly 500K per second to 45K per second. The patch will have no impact on workloads with no memory pressure or have relatively few mapped pages. It will have an unpredictable impact on the workload running on the CPU being flushed as it'll depend on how many TLB entries need to be refilled and how long that takes. Worst case, the TLB will be completely cleared of active entries when the target PFNs were not resident at all. [sasha.levin@oracle.com: trace tlb flush after disabling preemption in try_to_unmap_flush] Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Dave Hansen <dave.hansen@intel.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* x86: Store a per-cpu shadow copy of CR4Andy Lutomirski2015-02-041-13/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | Context switches and TLB flushes can change individual bits of CR4. CR4 reads take several cycles, so store a shadow copy of CR4 in a per-cpu variable. To avoid wasting a cache line, I added the CR4 shadow to cpu_tlbstate, which is already touched in switch_mm. The heaviest users of the cr4 shadow will be switch_mm and __switch_to_xtra, and __switch_to_xtra is called shortly after switch_mm during context switch, so the cacheline is likely to be hot. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Kees Cook <keescook@chromium.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Vince Weaver <vince@deater.net> Cc: "hillf.zj" <hillf.zj@alibaba-inc.com> Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/3a54dd3353fffbf84804398e00dfdc5b7c1afd7d.1414190806.git.luto@amacapital.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86: Clean up cr4 manipulationAndy Lutomirski2015-02-041-0/+37
| | | | | | | | | | | | | | | | | | | | | | | | | CR4 manipulation was split, seemingly at random, between direct (write_cr4) and using a helper (set/clear_in_cr4). Unfortunately, the set_in_cr4 and clear_in_cr4 helpers also poke at the boot code, which only a small subset of users actually wanted. This patch replaces all cr4 access in functions that don't leave cr4 exactly the way they found it with new helpers cr4_set_bits, cr4_clear_bits, and cr4_set_bits_and_update_boot. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Vince Weaver <vince@deater.net> Cc: "hillf.zj" <hillf.zj@alibaba-inc.com> Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/495a10bdc9e67016b8fd3945700d46cfd5c12c2f.1414190806.git.luto@amacapital.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
* mm, x86: Account for TLB flushes only when debuggingMel Gorman2014-01-251-3/+3
| | | | | | | | | | | | | | | | | | | | Bisection between 3.11 and 3.12 fingered commit 9824cf97 ("mm: vmstats: tlb flush counters") to cause overhead problems. The counters are undeniably useful but how often do we really need to debug TLB flush related issues? It does not justify taking the penalty everywhere so make it a debugging option. Signed-off-by: Mel Gorman <mgorman@suse.de> Tested-by: Davidlohr Bueso <davidlohr@hp.com> Reviewed-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Hugh Dickins <hughd@google.com> Cc: Alex Shi <alex.shi@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-XzxjntugxuwpxXhcrxqqh53b@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* mm: vmstats: track TLB flush stats on UP tooDave Hansen2013-09-111-6/+31
| | | | | | | | | | | | | | | | | | | | | | | | The previous patch doing vmstats for TLB flushes ("mm: vmstats: tlb flush counters") effectively missed UP since arch/x86/mm/tlb.c is only compiled for SMP. UP systems do not do remote TLB flushes, so compile those counters out on UP. arch/x86/kernel/cpu/mtrr/generic.c calls __flush_tlb() directly. This is probably an optimization since both the mtrr code and __flush_tlb() write cr4. It would probably be safe to make that a flush_tlb_all() (and then get these statistics), but the mtrr code is ancient and I'm hesitant to touch it other than to just stick in the counters. [akpm@linux-foundation.org: tweak comments] Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* x86, cleanups: Remove extra tab in __flush_tlb_one()Michael Wang2013-06-041-1/+1
| | | | | | | | | | Remove the extra tab in __flush_tlb_one(). CC: Alex Shi <alex.shi@intel.com> CC: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/51AD8902.60603@linux.vnet.ibm.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86/tlbflush.h: Define __native_flush_tlb_global_irq_disabled()Fenghua Yu2013-01-311-6/+12
| | | | | | | | | This function is called in __native_flush_tlb_global() and after apply_microcode_early(). Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Link: http://lkml.kernel.org/r/1356075872-3054-8-git-send-email-fenghua.yu@intel.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86, 386 removal: Remove CONFIG_INVLPGH. Peter Anvin2012-11-291-3/+0
| | | | | | | | All 486+ CPUs support INVLPG, so remove the fallback 386 support code. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Link: http://lkml.kernel.org/r/1354132230-21854-6-git-send-email-hpa@linux.intel.com
* x86/tlb: Fix build warning and crash when building for !SMPAlex Shi2012-07-201-2/+2
| | | | | | | | | | | | | The incompatible parameter of flush_tlb_mm_range cause build warning. Fix it by correct parameter. Ingo Molnar found that this could also cause a user space crash. Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Alex Shi <alex.shi@intel.com> Link: http://lkml.kernel.org/r/1342747103-19765-1-git-send-email-alex.shi@intel.com Signed-off-by: H. Peter Anvin <hpa@zytor.com>
* x86/tlb: do flush_tlb_kernel_range by 'invlpg'Alex Shi2012-06-271-6/+7
| | | | | | | | | | | | | | | | This patch do flush_tlb_kernel_range by 'invlpg'. The performance pay and gain was analyzed in previous patch (x86/flush_tlb: try flush_tlb_single one by one in flush_tlb_range). In the testing: http://lkml.org/lkml/2012/6/21/10 The pay is mostly covered by long kernel path, but the gain is still quite clear, memory access in user APP can increase 30+% when kernel execute this funtion. Signed-off-by: Alex Shi <alex.shi@intel.com> Link: http://lkml.kernel.org/r/1340845344-27557-10-git-send-email-alex.shi@intel.com Signed-off-by: H. Peter Anvin <hpa@zytor.com>
* x86/tlb: enable tlb flush range support for x86Alex Shi2012-06-271-3/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Not every tlb_flush execution moment is really need to evacuate all TLB entries, like in munmap, just few 'invlpg' is better for whole process performance, since it leaves most of TLB entries for later accessing. This patch also rewrite flush_tlb_range for 2 purposes: 1, split it out to get flush_blt_mm_range function. 2, clean up to reduce line breaking, thanks for Borislav's input. My micro benchmark 'mummap' http://lkml.org/lkml/2012/5/17/59 show that the random memory access on other CPU has 0~50% speed up on a 2P * 4cores * HT NHM EP while do 'munmap'. Thanks Yongjie's testing on this patch: ------------- I used Linux 3.4-RC6 w/ and w/o his patches as Xen dom0 and guest kernel. After running two benchmarks in Xen HVM guest, I found his patches brought about 1%~3% performance gain in 'kernel build' and 'netperf' testing, though the performance gain was not very stable in 'kernel build' testing. Some detailed testing results are below. Testing Environment: Hardware: Romley-EP platform Xen version: latest upstream Linux kernel: 3.4-RC6 Guest vCPU number: 8 NIC: Intel 82599 (10GB bandwidth) In 'kernel build' testing in guest: Command line | performance gain make -j 4 | 3.81% make -j 8 | 0.37% make -j 16 | -0.52% In 'netperf' testing, we tested TCP_STREAM with default socket size 16384 byte as large packet and 64 byte as small packet. I used several clients to add networking pressure, then 'netperf' server automatically generated several threads to response them. I also used large-size packet and small-size packet in the testing. Packet size | Thread number | performance gain 16384 bytes | 4 | 0.02% 16384 bytes | 8 | 2.21% 16384 bytes | 16 | 2.04% 64 bytes | 4 | 1.07% 64 bytes | 8 | 3.31% 64 bytes | 16 | 0.71% Signed-off-by: Alex Shi <alex.shi@intel.com> Link: http://lkml.kernel.org/r/1340845344-27557-8-git-send-email-alex.shi@intel.com Tested-by: Ren, Yongjie <yongjie.ren@intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
* x86/flush_tlb: try flush_tlb_single one by one in flush_tlb_rangeAlex Shi2012-06-271-14/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | x86 has no flush_tlb_range support in instruction level. Currently the flush_tlb_range just implemented by flushing all page table. That is not the best solution for all scenarios. In fact, if we just use 'invlpg' to flush few lines from TLB, we can get the performance gain from later remain TLB lines accessing. But the 'invlpg' instruction costs much of time. Its execution time can compete with cr3 rewriting, and even a bit more on SNB CPU. So, on a 512 4KB TLB entries CPU, the balance points is at: (512 - X) * 100ns(assumed TLB refill cost) = X(TLB flush entries) * 100ns(assumed invlpg cost) Here, X is 256, that is 1/2 of 512 entries. But with the mysterious CPU pre-fetcher and page miss handler Unit, the assumed TLB refill cost is far lower then 100ns in sequential access. And 2 HT siblings in one core makes the memory access more faster if they are accessing the same memory. So, in the patch, I just do the change when the target entries is less than 1/16 of whole active tlb entries. Actually, I have no data support for the percentage '1/16', so any suggestions are welcomed. As to hugetlb, guess due to smaller page table, and smaller active TLB entries, I didn't see benefit via my benchmark, so no optimizing now. My micro benchmark show in ideal scenarios, the performance improves 70 percent in reading. And in worst scenario, the reading/writing performance is similar with unpatched 3.4-rc4 kernel. Here is the reading data on my 2P * 4cores *HT NHM EP machine, with THP 'always': multi thread testing, '-t' paramter is thread number: with patch unpatched 3.4-rc4 ./mprotect -t 1 14ns 24ns ./mprotect -t 2 13ns 22ns ./mprotect -t 4 12ns 19ns ./mprotect -t 8 14ns 16ns ./mprotect -t 16 28ns 26ns ./mprotect -t 32 54ns 51ns ./mprotect -t 128 200ns 199ns Single process with sequencial flushing and memory accessing: with patch unpatched 3.4-rc4 ./mprotect 7ns 11ns ./mprotect -p 4096 -l 8 -n 10240 21ns 21ns [ hpa: http://lkml.kernel.org/r/1B4B44D9196EFF41AE41FDA404FC0A100BFF94@SHSMSX101.ccr.corp.intel.com has additional performance numbers. ] Signed-off-by: Alex Shi <alex.shi@intel.com> Link: http://lkml.kernel.org/r/1340845344-27557-3-git-send-email-alex.shi@intel.com Signed-off-by: H. Peter Anvin <hpa@zytor.com>
* Merge branch 'x86-mm-for-linus' of ↵Linus Torvalds2012-05-231-5/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 mm changes from Ingo Molnar: "This tree includes a micro-optimization that avoids cr3 switches during idling; it fixes corner cases and there's also small cleanups" Fix up trivial context conflict with the percpu_xx -> this_cpu_xx changes. * 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86-64: Fix accounting in kernel_physical_mapping_init() x86/tlb: Clean up and unify TLB_FLUSH_ALL definition x86: Drop obsolete ARCH_BOOTMEM support x86, tlb: Switch cr3 in leave_mm() only when needed x86/mm: Fix the size calculation of mapping tables
| * x86/tlb: Clean up and unify TLB_FLUSH_ALL definitionAlex Shi2012-05-181-5/+1
| | | | | | | | | | | | | | | | | | | | | | Since sizeof(long) is 4 in x86_32 mode, and it's 8 in x86_64 mode, sizeof(long long) is also 8 byte in x86_64 mode. use long mode can fit TLB_FLUSH_ALL defination here both in 32 or 64 bits mode. Signed-off-by: Alex Shi <alex.shi@intel.com> Link: http://lkml.kernel.org/n/tip-evv5bekiipi2pmyzdsy8lkkw@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | x86: replace percpu_xxx funcs with this_cpu_xxxAlex Shi2012-05-141-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since percpu_xxx() serial functions are duplicated with this_cpu_xxx(). Removing percpu_xxx() definition and replacing them by this_cpu_xxx() in code. There is no function change in this patch, just preparation for later percpu_xxx serial function removing. On x86 machine the this_cpu_xxx() serial functions are same as __this_cpu_xxx() without no unnecessary premmpt enable/disable. Thanks for Stephen Rothwell, he found and fixed a i386 build error in the patch. Also thanks for Andrew Morton, he kept updating the patchset in Linus' tree. Signed-off-by: Alex Shi <alex.shi@intel.com> Acked-by: Christoph Lameter <cl@gentwo.org> Acked-by: Tejun Heo <tj@kernel.org> Acked-by: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Tejun Heo <tj@kernel.org>
* | Disintegrate asm/system.h for X86David Howells2012-03-281-1/+1
|/ | | | | | | | Disintegrate asm/system.h for X86. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: H. Peter Anvin <hpa@zytor.com> cc: x86@kernel.org
* x86-32, mm: Add an initial page table for core bootstrappingBorislav Petkov2010-10-201-2/+0
| | | | | | | | | | | | This patch adds an initial page table with low mappings used exclusively for booting APs/resuming after ACPI suspend/machine restart. After this, there's no need to add low mappings to swapper_pg_dir and zap them later or create own swsusp PGD page solely for ACPI sleep needs - we have initial_page_table for that. Signed-off-by: Borislav Petkov <bp@alien8.de> LKML-Reference: <20101020070526.GA9588@liondog.tnic> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86: make zap_low_mapping could be used earlyYinghai Lu2009-06-121-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Only one cpu is there, just call __flush_tlb for it. Fixes the following boot warning on x86: [ 0.000000] Memory: 885032k/915540k available (5993k kernel code, 29844k reserved, 3842k data, 428k init, 0k highmem) [ 0.000000] virtual kernel memory layout: [ 0.000000] fixmap : 0xffe17000 - 0xfffff000 (1952 kB) [ 0.000000] vmalloc : 0xf8615000 - 0xffe15000 ( 120 MB) [ 0.000000] lowmem : 0xc0000000 - 0xf7e15000 ( 894 MB) [ 0.000000] .init : 0xc19a5000 - 0xc1a10000 ( 428 kB) [ 0.000000] .data : 0xc15da4bb - 0xc199af6c (3842 kB) [ 0.000000] .text : 0xc1000000 - 0xc15da4bb (5993 kB) [ 0.000000] Checking if this processor honours the WP bit even in supervisor mode...Ok. [ 0.000000] ------------[ cut here ]------------ [ 0.000000] WARNING: at kernel/smp.c:369 smp_call_function_many+0x50/0x1b0() [ 0.000000] Hardware name: System Product Name [ 0.000000] Modules linked in: [ 0.000000] Pid: 0, comm: swapper Not tainted 2.6.30-tip #52504 [ 0.000000] Call Trace: [ 0.000000] [<c104aa16>] warn_slowpath_common+0x65/0x95 [ 0.000000] [<c104aa58>] warn_slowpath_null+0x12/0x15 [ 0.000000] [<c1073bbe>] smp_call_function_many+0x50/0x1b0 [ 0.000000] [<c1037615>] ? do_flush_tlb_all+0x0/0x41 [ 0.000000] [<c1037615>] ? do_flush_tlb_all+0x0/0x41 [ 0.000000] [<c1073d4f>] smp_call_function+0x31/0x58 [ 0.000000] [<c1037615>] ? do_flush_tlb_all+0x0/0x41 [ 0.000000] [<c104f635>] on_each_cpu+0x26/0x65 [ 0.000000] [<c10374b5>] flush_tlb_all+0x19/0x1b [ 0.000000] [<c1032ab3>] zap_low_mappings+0x4d/0x56 [ 0.000000] [<c15d64b5>] ? printk+0x14/0x17 [ 0.000000] [<c19b42a8>] mem_init+0x23d/0x245 [ 0.000000] [<c19a56a1>] start_kernel+0x17a/0x2d5 [ 0.000000] [<c19a5347>] ? unknown_bootoption+0x0/0x19a [ 0.000000] [<c19a5039>] __init_begin+0x39/0x41 [ 0.000000] ---[ end trace 4eaa2a86a8e2da22 ]--- Reported-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
* Merge branch 'linus' into tracing/coreIngo Molnar2009-05-071-1/+1
|\ | | | | | | | | | | | | Merge reason: tracing/core was on a .30-rc1 base and was missing out on on a handful of tracing fixes present in .30-rc5-almost. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * FRV: Fix the section attribute on UP DECLARE_PER_CPU()David Howells2009-04-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In non-SMP mode, the variable section attribute specified by DECLARE_PER_CPU() does not agree with that specified by DEFINE_PER_CPU(). This means that architectures that have a small data section references relative to a base register may throw up linkage errors due to too great a displacement between where the base register points and the per-CPU variable. On FRV, the .h declaration says that the variable is in the .sdata section, but the .c definition says it's actually in the .data section. The linker throws up the following errors: kernel/built-in.o: In function `release_task': kernel/exit.c:78: relocation truncated to fit: R_FRV_GPREL12 against symbol `per_cpu__process_counts' defined in .data section in kernel/built-in.o kernel/exit.c:78: relocation truncated to fit: R_FRV_GPREL12 against symbol `per_cpu__process_counts' defined in .data section in kernel/built-in.o To fix this, DECLARE_PER_CPU() should simply apply the same section attribute as does DEFINE_PER_CPU(). However, this is made slightly more complex by virtue of the fact that there are several variants on DEFINE, so these need to be matched by variants on DECLARE. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | x86: use native register access for native tlb flushingChris Wright2009-04-231-4/+4
|/ | | | | | | | | | | | currently these are paravirtulaized, doesn't appear any callers rely on this (no pv_ops backends are using native_tlb and overriding cr3/4 access). [ Impact: fix lockdep warning with paravirt and function tracer ] Signed-off-by: Chris Wright <chrisw@sous-sol.org> LKML-Reference: <20090423172138.GR3036@sequoia.sous-sol.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* x86-64: Move TLB state from PDA to per-cpu and consolidate with 32-bit.Brian Gerst2009-01-191-5/+2
| | | | | Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
*-. Merge branches 'cpus4096', 'x86/cleanups' and 'x86/urgent' into x86/percpuIngo Molnar2009-01-151-4/+6
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| | * x86: smp.h move zap_low_mappings declartion to tlbflush.hJaswinder Singh Rajput2009-01-071-0/+2
| |/ |/| | | | | | | | | | | Impact: cleanup, moving NON-SMP stuff from smp.h Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * x86: change flush_tlb_others to take a const struct cpumaskRusty Russell2009-01-111-4/+4
|/ | | | | | | | | | | | | | | | | | | | | Impact: reduce stack usage, use new cpumask API. This is made a little more tricky by uv_flush_tlb_others which actually alters its argument, for an IPI to be sent to the remaining cpus in the mask. I solve this by allocating a cpumask_var_t for this case and falling back to IPI should this fail. To eliminate temporaries in the caller, all flush_tlb_others implementations now do the this-cpu-elimination step themselves. Note also the curious "cpus_or(f->flush_cpumask, cpumask, f->flush_cpumask)" which has been there since pre-git and yet f->flush_cpumask is always zero at this point. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Mike Travis <travis@sgi.com>
* x86: Fix ASM_X86__ header guardsH. Peter Anvin2008-10-221-3/+3
| | | | | | | | | Change header guards named "ASM_X86__*" to "_ASM_X86_*" since: a. the double underscore is ugly and pointless. b. no leading underscore violates namespace constraints. Signed-off-by: H. Peter Anvin <hpa@zytor.com>
* x86, um: ... and asm-x86 moveAl Viro2008-10-221-0/+178
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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