- 16 1月, 2009 2 次提交
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由 Andrew Morton 提交于
David points out that the idr_remove_all() function returns unused slabs to the kmem cache, but needs to zero them first or else they will be uninitialized upon next use. This causes crashes which have been observed in the firewire subsystem. He fixed this by zeroing the object before freeing it in idr_remove_all(). But we agree that simply removing the constructor and zeroing the object at allocation time is simpler than relying upon slab constructor machinery and might even be faster. This problem was introduced by "idr: make idr_remove rcu-safe" (commit cf481c20), which was first released in 2.6.27. There are no known codesites which trigger this bug in 2.6.27 or 2.6.28. The post-2.6.28 firewire changes are the only known triggerer. There might of course be not-yet-discovered triggerers in 2.6.27 and 2.6.28, and there might be out-of-tree triggerers which are added to those kernel versions. I'll let the -stable guys decide whether they want to backport this fix. Reported-by: NDavid Moore <dcm@acm.org> Cc: Stefan Richter <stefanr@s5r6.in-berlin.de> Cc: Nadia Derbey <Nadia.Derbey@bull.net> Cc: Paul E. McKenney <paulmck@us.ibm.com> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: Kristian Hgsberg <krh@redhat.com> Acked-by: NPekka Enberg <penberg@cs.helsinki.fi> Cc: <stable@kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Li Zefan 提交于
idr_get_new_above() and ida_get_new_above() return an id in the range of @staring_id ... 0x7fffffff, not 0 ... 0x7fffffff. Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 10 1月, 2009 1 次提交
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由 Artem Bityutskiy 提交于
The 'rb_first()', 'rb_last()', 'rb_next()' and 'rb_prev()' calls take a pointer to an RB node or RB root. They do not change the pointed objects, so add a 'const' qualifier in order to make life of the users of these functions easier. Indeed, if I have my own constant pointer &const struct my_type *p, and I call 'rb_next(&p->rb)', I get a GCC warning: warning: passing argument 1 of ‘rb_next’ discards qualifiers from pointer target type Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 09 1月, 2009 1 次提交
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由 Wu Fengguang 提交于
This is to avoid name clashes for the introduction of a global swap() macro. Signed-off-by: NWu Fengguang <fengguang.wu@intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 08 1月, 2009 1 次提交
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由 David Howells 提交于
Make VMAs per mm_struct as for MMU-mode linux. This solves two problems: (1) In SYSV SHM where nattch for a segment does not reflect the number of shmat's (and forks) done. (2) In mmap() where the VMA's vm_mm is set to point to the parent mm by an exec'ing process when VM_EXECUTABLE is specified, regardless of the fact that a VMA might be shared and already have its vm_mm assigned to another process or a dead process. A new struct (vm_region) is introduced to track a mapped region and to remember the circumstances under which it may be shared and the vm_list_struct structure is discarded as it's no longer required. This patch makes the following additional changes: (1) Regions are now allocated with alloc_pages() rather than kmalloc() and with no recourse to __GFP_COMP, so the pages are not composite. Instead, each page has a reference on it held by the region. Anything else that is interested in such a page will have to get a reference on it to retain it. When the pages are released due to unmapping, each page is passed to put_page() and will be freed when the page usage count reaches zero. (2) Excess pages are trimmed after an allocation as the allocation must be made as a power-of-2 quantity of pages. (3) VMAs are added to the parent MM's R/B tree and mmap lists. As an MM may end up with overlapping VMAs within the tree, the VMA struct address is appended to the sort key. (4) Non-anonymous VMAs are now added to the backing inode's prio list. (5) Holes may be punched in anonymous VMAs with munmap(), releasing parts of the backing region. The VMA and region structs will be split if necessary. (6) sys_shmdt() only releases one attachment to a SYSV IPC shared memory segment instead of all the attachments at that addresss. Multiple shmat()'s return the same address under NOMMU-mode instead of different virtual addresses as under MMU-mode. (7) Core dumping for ELF-FDPIC requires fewer exceptions for NOMMU-mode. (8) /proc/maps is now the global list of mapped regions, and may list bits that aren't actually mapped anywhere. (9) /proc/meminfo gains a line (tagged "MmapCopy") that indicates the amount of RAM currently allocated by mmap to hold mappable regions that can't be mapped directly. These are copies of the backing device or file if not anonymous. These changes make NOMMU mode more similar to MMU mode. The downside is that NOMMU mode requires some extra memory to track things over NOMMU without this patch (VMAs are no longer shared, and there are now region structs). Signed-off-by: NDavid Howells <dhowells@redhat.com> Tested-by: NMike Frysinger <vapier.adi@gmail.com> Acked-by: NPaul Mundt <lethal@linux-sh.org>
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- 07 1月, 2009 13 次提交
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由 Ingo Molnar 提交于
CONFIG_FRAME_POINTERS=y results in much better debug info for the kernel (clear and precise backtraces), with the only drawback being a ~1% increase in kernel size. So offer it unconditionally and enable it by default. Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Eric Dumazet 提交于
For NR_CPUS >= 16 values, FBC_BATCH is 2*NR_CPUS Considering more and more distros are using high NR_CPUS values, it makes sense to use a more sensible value for FBC_BATCH, and get rid of NR_CPUS. A sensible value is 2*num_online_cpus(), with a minimum value of 32 (This minimum value helps branch prediction in __percpu_counter_add()) We already have a hotcpu notifier, so we can adjust FBC_BATCH dynamically. We rename FBC_BATCH to percpu_counter_batch since its not a constant anymore. Signed-off-by: NEric Dumazet <dada1@cosmosbay.com> Acked-by: NDavid S. Miller <davem@davemloft.net> Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Pavel Machek 提交于
It decodes "\n" as 0, which is bad, because stray echo into backlight will turn your backlight off, etc... Signed-off-by: NPavel Machek <pavel@suse.cz> Cc: Yi Yang <yi.y.yang@intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Harvey Harrison 提交于
Suppresses sparse warning: lib/proportions.c:159:16: warning: context imbalance in 'prop_get_global': wrong count at exit lib/proportions.c:159:16: context 'RCU': wanted 0, got 1 lib/proportions.c:164:2: warning: context imbalance in 'prop_put_global': unexpected unlock lib/proportions.c:164:2: context 'RCU': wanted 0, got -1 Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Harvey Harrison 提交于
radix_tree_preloads is unused outside of this file, make it static. Noticed by sparse: lib/radix-tree.c:84:1: warning: symbol 'per_cpu__radix_tree_preloads' was not declared. Should it be static? Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Harvey Harrison 提交于
pos is always set before being used, no need to declare a second one inside the if() block. lib/prio_heap.c:34:7: warning: symbol 'pos' shadows an earlier one lib/prio_heap.c:30:6: originally declared here Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Alexey Dobriyan 提交于
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com> Cc: Gabor Gombas <gombasg@sztaki.hu> Cc: Jan Beulich <jbeulich@novell.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Ingo Molnar <mingo@elte.hu>, Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Viktor Rosendahl 提交于
This used to work unpatched with older kernels, during the development phase of mtdoops. Before commit e3e8a75d a space was printed with console_loglevel set to 15, which probably flushed the oops message as a side effect. This is another patch from the Nokia N810 kernel. Signed-off-by: NViktor Rosendahl <viktor.rosendahl@nokia.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Woodhouse <dwmw2@infradead.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Kay Sievers 提交于
Signed-off-by: NKay Sievers <kay.sievers@vrfy.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
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由 Wu Fengguang 提交于
Cleanup pr_debug_write() to reduce one level of indentation. Cc: Marcel Holtmann <marcel@holtmann.org> Acked-by: NJason Baron <jbaron@redhat.com> Signed-off-by: NWu Fengguang <fengguang.wu@intel.com> Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
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由 Ming Lei 提交于
We need to return the result of uevent sending by netlink to caller, when uevent_helper is disabled and CONFIG_NET is defined. Signed-off-by: NMing Lei <tom.leiming@gmail.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
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由 Tejun Heo 提交于
kobject_uevent_env() uses envp_ext[] as verbatim format string which can cause problems ranging from unexpectedly mangled string to oops if a string in envp_ext[] contains substring which can be interpreted as format. Fix it. Signed-off-by: NTejun Heo <tj@kernel.org> Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
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由 Matthew Wilcox 提交于
Removing the completion from klist_node reduces its size from 64 bytes to 28 on x86-64. To maintain the semantics of klist_remove(), we add a single list of klist nodes which are pending deletion and scan them. Signed-off-by: NMatthew Wilcox <willy@linux.intel.com> Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
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- 06 1月, 2009 1 次提交
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由 Wu Fengguang 提交于
And some 80-line cleanups. Signed-off-by: NWu Fengguang <wfg@linux.intel.com> Signed-off-by: NJiri Kosina <jkosina@suse.cz>
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- 04 1月, 2009 2 次提交
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由 Jesper Juhl 提交于
There's no point in including the linux/swiotlb.h header twice in lib/swiotlb.c - this patch gets rid of the unneeded include. Signed-off-by: NJesper Juhl <jj@chaosbits.net> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Linus Torvalds 提交于
Before, when we only ever printed out the pointer value itself, a NULL pointer would never cause issues and might as well be printed out as just its numeric value. However, with the extended %p formats, especially %pR, we might validly want to print out resources for debugging. And sometimes they don't even exist, and the resource pointer is just NULL. Print it out as such, rather than oopsing. This is a more generic version of a patch done by Trent Piepho (catching all %p cases rather than just %pR, and using "(null)" instead of "[NULL]" to match glibc). Requested-by: NTrent Piepho <xyzzy@speakeasy.org> Acked-by: NHarvey Harrison <harvey.harrison@gmail.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 03 1月, 2009 1 次提交
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由 Roland Dreier 提交于
Impact: cleanup, reduce kernel size a bit The current kernel build warns: WARNING: vmlinux.o(.text+0x11458): Section mismatch in reference from the function swiotlb_alloc_boot() to the function .init.text:__alloc_bootmem_low() The function swiotlb_alloc_boot() references the function __init __alloc_bootmem_low(). This is often because swiotlb_alloc_boot lacks a __init annotation or the annotation of __alloc_bootmem_low is wrong. WARNING: vmlinux.o(.text+0x1011f2): Section mismatch in reference from the function swiotlb_late_init_with_default_size() to the function .init.text:__alloc_bootmem_low() The function swiotlb_late_init_with_default_size() references the function __init __alloc_bootmem_low(). This is often because swiotlb_late_init_with_default_size lacks a __init annotation or the annotation of __alloc_bootmem_low is wrong. and indeed the functions calling __alloc_bootmem_low() can be marked __init as well. Signed-off-by: NRoland Dreier <rolandd@cisco.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 01 1月, 2009 4 次提交
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由 Rusty Russell 提交于
Impact: new debug CONFIG options This helps find unconverted code. It currently breaks compile horribly, but we never wanted a flag day so that's expected. Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
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由 Rusty Russell 提交于
Impact: extra safety checks during transition When CONFIG_CPUMASKS_OFFSTACK is set, the new cpumask_ operators only use bits up to nr_cpu_ids, not NR_CPUS. Using the old cpus_ operators on these masks can mean accessing undefined bits. After some discussion, Mike and I decided to err on the side of caution; we zero the "undefined" bits in alloc_cpumask_var_node() until all the old cpumask functions are removed. Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
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由 Rusty Russell 提交于
Impact: New API As the name suggests. For the moment everyone uses the generic one. Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
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由 Li Zefan 提交于
Impact: fix kernel-doc alloc_bootmem_cpumask_var() returns avoid. Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com> Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
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- 29 12月, 2008 2 次提交
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由 Peter Zijlstra 提交于
Impact: fix lockdep false positives Classify percpu_counter instances similar to regular lock objects -- that is, per instantiation site. The networking code has increased its use of percpu_counters, which leads to false positives if they are treated as a single class. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Akinobu Mita 提交于
Currently fault-injection capability for SLAB allocator is only available to SLAB. This patch makes it available to SLUB, too. [penberg@cs.helsinki.fi: unify slab and slub implementations] Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com> Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
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- 28 12月, 2008 5 次提交
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由 FUJITA Tomonori 提交于
Impact: cleanup swiotlb uses EXPORT_SYMBOL in an inconsistent way. Some functions use EXPORT_SYMBOL at the end of functions. Some use it at the end of swiotlb.c. This cleans up swiotlb to use EXPORT_SYMBOL in a consistent way (at the end of functions). Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 FUJITA Tomonori 提交于
Impact: cleanup Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Becky Bruce 提交于
Impact: extend code for highmem - existing users unaffected On highmem systems, the original dma buffer might not have a virtual mapping - we need to kmap it in to perform the bounce. Extract the code that does the actual copy into a function that does the kmap if highmem is enabled, and default to the normal swiotlb memcpy if not. [ ported by Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> ] Signed-off-by: NBecky Bruce <beckyb@kernel.crashing.org> Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Becky Bruce 提交于
Impact: refactor code, cleanup When we enable swiotlb for platforms that support HIGHMEM, we can no longer store the virtual address of the original dma buffer, because that buffer might not have a permament mapping. Change the swiotlb code to instead store the physical address of the original buffer. Signed-off-by: NBecky Bruce <beckyb@kernel.crashing.org> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Jeremy Fitzhardinge 提交于
Impact: extend functions with a (yet unused) parameter, update callsites Some architectures need it - in preparation for highmem swiotlb. Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 25 12月, 2008 3 次提交
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由 Herbert Xu 提交于
Selecting CRYPTO_CRC32C is not enough as CRYPTO which CRYPTO_CRC32C depends on may be disabled. This patch adds the select on CRYPTO. Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
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由 Adrian-Ken Rueegsegger 提交于
The latest shash changes leave crc32c undefined: [...] Building modules, stage 2. MODPOST 1381 modules ERROR: "crc32c" [net/sctp/sctp.ko] undefined! ERROR: "crc32c" [net/ipv4/netfilter/nf_nat_proto_sctp.ko] undefined! Adding EXPORT_SYMBOL(crc32c) to lib/libcrc32c.c fixes the compile error. This patch has been compile-tested only. Signed-off-by: NAdrian-Ken Rueegsegger <rueegsegger@swiss-it.ch> Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
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由 Herbert Xu 提交于
This patch swaps the role of libcrc32c and crc32c. Previously the implementation was in libcrc32c and crc32c was a wrapper. Now the code is in crc32c and libcrc32c just calls the crypto layer. The reason for the change is to tap into the algorithm selection capability of the crypto API so that optimised implementations such as the one utilising Intel's CRC32C instruction can be used where available. Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
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- 19 12月, 2008 3 次提交
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由 Mike Travis 提交于
Impact: New kerneldoc comments Additional documentation added to all the alloc_cpumask and free_cpumask functions. Signed-off-by: NMike Travis <travis@sgi.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (minor additions)
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由 Mike Travis 提交于
Impact: New API This will be needed in x86 code to allocate the domain and old_domain cpumasks on the same node as where the containing irq_cfg struct is allocated. (Also fixes double-dump_stack on rare CONFIG_DEBUG_PER_CPU_MAPS case) Signed-off-by: NMike Travis <travis@sgi.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (re-impl alloc_cpumask_var)
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由 Paul E. McKenney 提交于
This patch fixes a long-standing performance bug in classic RCU that results in massive internal-to-RCU lock contention on systems with more than a few hundred CPUs. Although this patch creates a separate flavor of RCU for ease of review and patch maintenance, it is intended to replace classic RCU. This patch still handles stress better than does mainline, so I am still calling it ready for inclusion. This patch is against the -tip tree. Nevertheless, experience on an actual 1000+ CPU machine would still be most welcome. Most of the changes noted below were found while creating an rcutiny (which should permit ejecting the current rcuclassic) and while doing detailed line-by-line documentation. Updates from v9 (http://lkml.org/lkml/2008/12/2/334): o Fixes from remainder of line-by-line code walkthrough, including comment spelling, initialization, undesirable narrowing due to type conversion, removing redundant memory barriers, removing redundant local-variable initialization, and removing redundant local variables. I do not believe that any of these fixes address the CPU-hotplug issues that Andi Kleen was seeing, but please do give it a whirl in case the machine is smarter than I am. A writeup from the walkthrough may be found at the following URL, in case you are suffering from terminal insomnia or masochism: http://www.kernel.org/pub/linux/kernel/people/paulmck/tmp/rcutree-walkthrough.2008.12.16a.pdf o Made rcutree tracing use seq_file, as suggested some time ago by Lai Jiangshan. o Added a .csv variant of the rcudata debugfs trace file, to allow people having thousands of CPUs to drop the data into a spreadsheet. Tested with oocalc and gnumeric. Updated documentation to suit. Updates from v8 (http://lkml.org/lkml/2008/11/15/139): o Fix a theoretical race between grace-period initialization and force_quiescent_state() that could occur if more than three jiffies were required to carry out the grace-period initialization. Which it might, if you had enough CPUs. o Apply Ingo's printk-standardization patch. o Substitute local variables for repeated accesses to global variables. o Fix comment misspellings and redundant (but harmless) increments of ->n_rcu_pending (this latter after having explicitly added it). o Apply checkpatch fixes. Updates from v7 (http://lkml.org/lkml/2008/10/10/291): o Fixed a number of problems noted by Gautham Shenoy, including the cpu-stall-detection bug that he was having difficulty convincing me was real. ;-) o Changed cpu-stall detection to wait for ten seconds rather than three in order to reduce false positive, as suggested by Ingo Molnar. o Produced a design document (http://lwn.net/Articles/305782/). The act of writing this document uncovered a number of both theoretical and "here and now" bugs as noted below. o Fix dynticks_nesting accounting confusion, simplify WARN_ON() condition, fix kerneldoc comments, and add memory barriers in dynticks interface functions. o Add more data to tracing. o Remove unused "rcu_barrier" field from rcu_data structure. o Count calls to rcu_pending() from scheduling-clock interrupt to use as a surrogate timebase should jiffies stop counting. o Fix a theoretical race between force_quiescent_state() and grace-period initialization. Yes, initialization does have to go on for some jiffies for this race to occur, but given enough CPUs... Updates from v6 (http://lkml.org/lkml/2008/9/23/448): o Fix a number of checkpatch.pl complaints. o Apply review comments from Ingo Molnar and Lai Jiangshan on the stall-detection code. o Fix several bugs in !CONFIG_SMP builds. o Fix a misspelled config-parameter name so that RCU now announces at boot time if stall detection is configured. o Run tests on numerous combinations of configurations parameters, which after the fixes above, now build and run correctly. Updates from v5 (http://lkml.org/lkml/2008/9/15/92, bad subject line): o Fix a compiler error in the !CONFIG_FANOUT_EXACT case (blew a changeset some time ago, and finally got around to retesting this option). o Fix some tracing bugs in rcupreempt that caused incorrect totals to be printed. o I now test with a more brutal random-selection online/offline script (attached). Probably more brutal than it needs to be on the people reading it as well, but so it goes. o A number of optimizations and usability improvements: o Make rcu_pending() ignore the grace-period timeout when there is no grace period in progress. o Make force_quiescent_state() avoid going for a global lock in the case where there is no grace period in progress. o Rearrange struct fields to improve struct layout. o Make call_rcu() initiate a grace period if RCU was idle, rather than waiting for the next scheduling clock interrupt. o Invoke rcu_irq_enter() and rcu_irq_exit() only when idle, as suggested by Andi Kleen. I still don't completely trust this change, and might back it out. o Make CONFIG_RCU_TRACE be the single config variable manipulated for all forms of RCU, instead of the prior confusion. o Document tracing files and formats for both rcupreempt and rcutree. Updates from v4 for those missing v5 given its bad subject line: o Separated dynticks interface so that NMIs and irqs call separate functions, greatly simplifying it. In particular, this code no longer requires a proof of correctness. ;-) o Separated dynticks state out into its own per-CPU structure, avoiding the duplicated accounting. o The case where a dynticks-idle CPU runs an irq handler that invokes call_rcu() is now correctly handled, forcing that CPU out of dynticks-idle mode. o Review comments have been applied (thank you all!!!). For but one example, fixed the dynticks-ordering issue that Manfred pointed out, saving me much debugging. ;-) o Adjusted rcuclassic and rcupreempt to handle dynticks changes. Attached is an updated patch to Classic RCU that applies a hierarchy, greatly reducing the contention on the top-level lock for large machines. This passes 10-hour concurrent rcutorture and online-offline testing on 128-CPU ppc64 without dynticks enabled, and exposes some timekeeping bugs in presence of dynticks (exciting working on a system where "sleep 1" hangs until interrupted...), which were fixed in the 2.6.27 kernel. It is getting more reliable than mainline by some measures, so the next version will be against -tip for inclusion. See also Manfred Spraul's recent patches (or his earlier work from 2004 at http://marc.info/?l=linux-kernel&m=108546384711797&w=2). We will converge onto a common patch in the fullness of time, but are currently exploring different regions of the design space. That said, I have already gratefully stolen quite a few of Manfred's ideas. This patch provides CONFIG_RCU_FANOUT, which controls the bushiness of the RCU hierarchy. Defaults to 32 on 32-bit machines and 64 on 64-bit machines. If CONFIG_NR_CPUS is less than CONFIG_RCU_FANOUT, there is no hierarchy. By default, the RCU initialization code will adjust CONFIG_RCU_FANOUT to balance the hierarchy, so strongly NUMA architectures may choose to set CONFIG_RCU_FANOUT_EXACT to disable this balancing, allowing the hierarchy to be exactly aligned to the underlying hardware. Up to two levels of hierarchy are permitted (in addition to the root node), allowing up to 16,384 CPUs on 32-bit systems and up to 262,144 CPUs on 64-bit systems. I just know that I am going to regret saying this, but this seems more than sufficient for the foreseeable future. (Some architectures might wish to set CONFIG_RCU_FANOUT=4, which would limit such architectures to 64 CPUs. If this becomes a real problem, additional levels can be added, but I doubt that it will make a significant difference on real hardware.) In the common case, a given CPU will manipulate its private rcu_data structure and the rcu_node structure that it shares with its immediate neighbors. This can reduce both lock and memory contention by multiple orders of magnitude, which should eliminate the need for the strange manipulations that are reported to be required when running Linux on very large systems. Some shortcomings: o More bugs will probably surface as a result of an ongoing line-by-line code inspection. Patches will be provided as required. o There are probably hangs, rcutorture failures, &c. Seems quite stable on a 128-CPU machine, but that is kind of small compared to 4096 CPUs. However, seems to do better than mainline. Patches will be provided as required. o The memory footprint of this version is several KB larger than rcuclassic. A separate UP-only rcutiny patch will be provided, which will reduce the memory footprint significantly, even compared to the old rcuclassic. One such patch passes light testing, and has a memory footprint smaller even than rcuclassic. Initial reaction from various embedded guys was "it is not worth it", so am putting it aside. Credits: o Manfred Spraul for ideas, review comments, and bugs spotted, as well as some good friendly competition. ;-) o Josh Triplett, Ingo Molnar, Peter Zijlstra, Mathieu Desnoyers, Lai Jiangshan, Andi Kleen, Andy Whitcroft, and Andrew Morton for reviews and comments. o Thomas Gleixner for much-needed help with some timer issues (see patches below). o Jon M. Tollefson, Tim Pepper, Andrew Theurer, Jose R. Santos, Andy Whitcroft, Darrick Wong, Nishanth Aravamudan, Anton Blanchard, Dave Kleikamp, and Nathan Lynch for keeping machines alive despite my heavy abuse^Wtesting. Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 18 12月, 2008 1 次提交
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由 Marcel Holtmann 提交于
Both messages are missing the newline and thus dmesg output gets scrambled. Signed-off-by: NMarcel Holtmann <marcel@holtmann.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
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