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2006-03-27[PATCH] unify pfn_to_page: arm26 pfn_to_pageKAMEZAWA Hiroyuki
arm26 can use generic funcs. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Ian Molton <spyro@f2s.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-26[PATCH] bitops: arm26: use generic bitopsAkinobu Mita
- remove __{,test_and_}{set,clear,change}_bit() and test_bit() - remove ffz() - remove __ffs() - remove generic_fls() - remove generic_fls64() - remove generic_ffs() - remove sched_find_first_bit() - remove generic_hweight{32,16,8}() Signed-off-by: Akinobu Mita <mita@miraclelinux.com> Cc: Ian Molton <spyro@f2s.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-25[PATCH] POLLRDHUP/EPOLLRDHUP handling for half-closed devices notificationsDavide Libenzi
Implement the half-closed devices notifiation, by adding a new POLLRDHUP (and its alias EPOLLRDHUP) bit to the existing poll/select sets. Since the existing POLLHUP handling, that does not report correctly half-closed devices, was feared to be changed, this implementation leaves the current POLLHUP reporting unchanged and simply add a new bit that is set in the few places where it makes sense. The same thing was discussed and conceptually agreed quite some time ago: http://lkml.org/lkml/2003/7/12/116 Since this new event bit is added to the existing Linux poll infrastruture, even the existing poll/select system calls will be able to use it. As far as the existing POLLHUP handling, the patch leaves it as is. The pollrdhup-2.6.16.rc5-0.10.diff defines the POLLRDHUP for all the existing archs and sets the bit in the six relevant files. The other attached diff is the simple change required to sys/epoll.h to add the EPOLLRDHUP definition. There is "a stupid program" to test POLLRDHUP delivery here: http://www.xmailserver.org/pollrdhup-test.c It tests poll(2), but since the delivery is same epoll(2) will work equally. Signed-off-by: Davide Libenzi <davidel@xmailserver.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-15[PATCH] add asm-generic/mman.hMichael S. Tsirkin
Make new MADV_REMOVE, MADV_DONTFORK, MADV_DOFORK consistent across all arches. The idea is to make it possible to use them portably even before distros include them in libc headers. Move common flags to asm-generic/mman.h Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il> Cc: Roland Dreier <rolandd@cisco.com> Cc: Badari Pulavarty <pbadari@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-15[PATCH] madvise MADV_DONTFORK/MADV_DOFORKMichael S. Tsirkin
Currently, copy-on-write may change the physical address of a page even if the user requested that the page is pinned in memory (either by mlock or by get_user_pages). This happens if the process forks meanwhile, and the parent writes to that page. As a result, the page is orphaned: in case of get_user_pages, the application will never see any data hardware DMA's into this page after the COW. In case of mlock'd memory, the parent is not getting the realtime/security benefits of mlock. In particular, this affects the Infiniband modules which do DMA from and into user pages all the time. This patch adds madvise options to control whether memory range is inherited across fork. Useful e.g. for when hardware is doing DMA from/into these pages. Could also be useful to an application wanting to speed up its forks by cutting large areas out of consideration. Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il> Acked-by: Hugh Dickins <hugh@veritas.com> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-01[PATCH] arm26: add __kernel_old_dev_t for nfsdAlexey Dobriyan
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Ian Molton <spyro@f2s.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-01[PATCH] arm26: drop first arg of prepare_arch_switch, finish_arch_switchAlexey Dobriyan
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Ian Molton <spyro@f2s.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-01[PATCH] arm26: drop local task_running copyAlexey Dobriyan
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Ian Molton <spyro@f2s.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-01[PATCH] arm26: remove irq_exit() from hardirq.hAlexey Dobriyan
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Ian Molton <spyro@f2s.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-01[PATCH] arm26: fix warnings about NR_IRQS being not definedAlexey Dobriyan
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Ian Molton <spyro@f2s.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-02-01[PATCH] arm26: fix find_first_zero_bit related warningsAlexey Dobriyan
include/linux/nodemask.h: In function `__first_unset_node': include/linux/nodemask.h:254: warning: passing arg 1 of `_find_first_zero_bit_le' discards qualifiers from pointer target type fs/minix/bitmap.c: In function `minix_new_block': fs/minix/bitmap.c:89: warning: passing arg 1 of `_find_first_zero_bit_le' from incompatible pointer type Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Ian Molton <spyro@f2s.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-17[PATCH] arm26: add L1_CACHE_SHIFTAlexey Dobriyan
Fix reiserfs compilation as a side effect =) Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Ian Molton <spyro@f2s.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-17[PATCH] fix arm26 THREAD_SIZEAdrian Bunk
arm26 currently has a 256 kB THREAD_SIZE (sic). Looking at the comment in the code, this seems to be based on a misunderstanding. The comment says: this needs attention (see kernel/fork.c which gets a nice div by zero if this is lower than 8*32768 kernel/fork.c does: max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE) Therefore, a division by 0 is impossible for all reasonable cases with THREAD_SIZE >= PAGE_SIZE. Since the minimum PAGE_SIZE Linux uses on the arm26 architecture is 16k, PAGE_SIZE should be sufficient for THREAD_SIZE. Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Ian Molton <spyro@f2s.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-12[PATCH] death of get_thread_info/put_thread_infoAl Viro
{get,put}_thread_info() were introduced in 2.5.4 and never had been called by anything in the tree. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-12[PATCH] arm26: task_stack_page()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-12[PATCH] arm26: task_pt_regs()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-12[PATCH] arm26: task_thread_info()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-12[PATCH] sched: add cacheflush() asmIngo Molnar
Add per-arch sched_cacheflush() which is a write-back cacheflush used by the migration-cost calibration code at bootup time. Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-10[PATCH] Generic ioctl.hBrian Gerst
Most arches copied the i386 ioctl.h. Combine them into a generic header. Signed-off-by: Brian Gerst <bgerst@didntduck.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-09[PATCH] mutex subsystem, add atomic_xchg() to all archesIngo Molnar
add atomic_xchg() to all the architectures. Needed by the new mutex code. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@infradead.org>
2006-01-09[PATCH] consolidate asm/futex.hJeff Dike
Most of the architectures have the same asm/futex.h. This consolidates them into asm-generic, with the arches including it from their own asm/futex.h. In the case of UML, this reverts the old broken futex.h and goes back to using the same one as almost everyone else. Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06[PATCH] atomic_long_t & include/asm-generic/atomic.h V2Christoph Lameter
Several counters already have the need to use 64 atomic variables on 64 bit platforms (see mm_counter_t in sched.h). We have to do ugly ifdefs to fall back to 32 bit atomic on 32 bit platforms. The VM statistics patch that I am working on will also make more extensive use of atomic64. This patch introduces a new type atomic_long_t by providing definitions in asm-generic/atomic.h that works similar to the c "long" type. Its 32 bits on 32 bit platforms and 64 bits on 64 bit platforms. Also cleans up the determination of the mm_counter_t in sched.h. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06[PATCH] madvise(MADV_REMOVE): remove pages from tmpfs shm backing storeBadari Pulavarty
Here is the patch to implement madvise(MADV_REMOVE) - which frees up a given range of pages & its associated backing store. Current implementation supports only shmfs/tmpfs and other filesystems return -ENOSYS. "Some app allocates large tmpfs files, then when some task quits and some client disconnect, some memory can be released. However the only way to release tmpfs-swap is to MADV_REMOVE". - Andrea Arcangeli Databases want to use this feature to drop a section of their bufferpool (shared memory segments) - without writing back to disk/swap space. This feature is also useful for supporting hot-plug memory on UML. Concerns raised by Andrew Morton: - "We have no plan for holepunching! If we _do_ have such a plan (or might in the future) then what would the API look like? I think sys_holepunch(fd, start, len), so we should start out with that." - Using madvise is very weird, because people will ask "why do I need to mmap my file before I can stick a hole in it?" - None of the other madvise operations call into the filesystem in this manner. A broad question is: is this capability an MM operation or a filesytem operation? truncate, for example, is a filesystem operation which sometimes has MM side-effects. madvise is an mm operation and with this patch, it gains FS side-effects, only they're really, really significant ones." Comments: - Andrea suggested the fs operation too but then it's more efficient to have it as a mm operation with fs side effects, because they don't immediatly know fd and physical offset of the range. It's possible to fixup in userland and to use the fs operation but it's more expensive, the vmas are already in the kernel and we can use them. Short term plan & Future Direction: - We seem to need this interface only for shmfs/tmpfs files in the short term. We have to add hooks into the filesystem for correctness and completeness. This is what this patch does. - In the future, plan is to support both fs and mmap apis also. This also involves (other) filesystem specific functions to be implemented. - Current patch doesn't support VM_NONLINEAR - which can be addressed in the future. Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Andrea Arcangeli <andrea@suse.de> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Cc: Ulrich Drepper <drepper@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-03[FLS64]: generic versionStephen Hemminger
Signed-off-by: Stephen Hemminger <shemminger@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-14[PATCH] atomic: inc_not_zeroNick Piggin
Introduce an atomic_inc_not_zero operation. Make this a special case of atomic_add_unless because lockless pagecache actually wants atomic_inc_not_negativeone due to its offset refcount. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-14[PATCH] atomic: cmpxchgNick Piggin
Introduce an atomic_cmpxchg operation. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-31[PATCH] semaphore: Remove __MUTEX_INITIALIZER()Arthur Othieno
__MUTEX_INITIALIZER() has no users, and equates to the more commonly used DECLARE_MUTEX(), thus making it pretty much redundant. Remove it for good. Signed-off-by: Arthur Othieno <a.othieno@bluewin.ch> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-31[PATCH] vm: remove unused/broken page_pte[_prot] macrosTejun Heo
This patch removes page_pte_prot and page_pte macros from all architectures. Some architectures define both, some only page_pte (broken) and others none. These macros are not used anywhere. page_pte_prot(page, prot) is identical to mk_pte(page, prot) and page_pte(page) is identical to page_pte_prot(page, __pgprot(0)). * The following architectures define both page_pte_prot and page_pte arm, arm26, ia64, sh64, sparc, sparc64 * The following architectures define only page_pte (broken) frv, i386, m32r, mips, sh, x86-64 * All other architectures define neither Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-31[PATCH] unify sys_ptrace prototypeChristoph Hellwig
Make sure we always return, as all syscalls should. Also move the common prototype to <linux/syscalls.h> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30[PATCH] mm: tlb_finish_mmu forget rssHugh Dickins
zap_pte_range has been counting the pages it frees in tlb->freed, then tlb_finish_mmu has used that to update the mm's rss. That got stranger when I added anon_rss, yet updated it by a different route; and stranger when rss and anon_rss became mm_counters with special access macros. And it would no longer be viable if we're relying on page_table_lock to stabilize the mm_counter, but calling tlb_finish_mmu outside that lock. Remove the mmu_gather's freed field, let tlb_finish_mmu stick to its own business, just decrement the rss mm_counter in zap_pte_range (yes, there was some point to batching the update, and a subsequent patch restores that). And forget the anal paranoia of first reading the counter to avoid going negative - if rss does go negative, just fix that bug. Remove the mmu_gather's flushes and avoided_flushes from arm and arm26: no use was being made of them. But arm26 alone was actually using the freed, in the way some others use need_flush: give it a need_flush. arm26 seems to prefer spaces to tabs here: respect that. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30[PATCH] mm: tlb_is_full_mm was obscureHugh Dickins
tlb_is_full_mm? What does that mean? The TLB is full? No, it means that the mm's last user has gone and the whole mm is being torn down. And it's an inline function because sparc64 uses a different (slightly better) "tlb_frozen" name for the flag others call "fullmm". And now the ptep_get_and_clear_full macro used in zap_pte_range refers directly to tlb->fullmm, which would be wrong for sparc64. Rather than correct that, I'd prefer to scrap tlb_is_full_mm altogether, and change sparc64 to just use the same poor name as everyone else - is that okay? Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30[PATCH] mm: tlb_gather_mmu get_cpu_varHugh Dickins
tlb_gather_mmu dates from before kernel preemption was allowed, and uses smp_processor_id or __get_cpu_var to find its per-cpu mmu_gather. That works because it's currently only called after getting page_table_lock, which is not dropped until after the matching tlb_finish_mmu. But don't rely on that, it will soon change: now disable preemption internally by proper get_cpu_var in tlb_gather_mmu, put_cpu_var in tlb_finish_mmu. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-21[PATCH] Remove unused var from asm/futex.hPaolo 'Blaisorblade' Giarrusso
As recently done by Russell King for ARM, commit 4732efbeb997189d9f9b04708dc26bf8613ed721 introduces a generic asm/futex.h copied along most arches, which includes a "-ENOSYS support" to be changed if needed. However, it includes an unused var (taken from the "real" version) which GCC warns about. Remove it from all arches having that file version (i.e. same GIT id). $ git-diff-tree -r HEAD and $ git-ls-tree -r HEAD include/|grep 9feff4ce1424bc390608326240be369eb13aa648 may be more interesting than looking at the patch itself, to make sure I've just copied the arm header to all other archs having the original dummy version of this file. Cc: Jakub Jelinek <jakub@redhat.com> Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-13[PATCH] feature removal of io_remap_page_range()Randy Dunlap
As written in Documentation/feature-removal-schedule.txt, remove the io_remap_page_range() kernel API. Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-10[PATCH] include/asm-arm26/hardirq.h: remove #define irq_enter()Adrian Bunk
This patch removes a #define for irq_enter that is superfluous due to a similar one in include/linux/hardirq.h. Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-07[PATCH] Clean up struct flock64 definitionsStephen Rothwell
This patch gathers all the struct flock64 definitions (and the operations), puts them under !CONFIG_64BIT and cleans up the arch files. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-07[PATCH] Clean up struct flock definitionsStephen Rothwell
This patch just gathers together all the struct flock definitions except xtensa into asm-generic/fcntl.h. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-07[PATCH] Clean up the fcntl operationsStephen Rothwell
This patch puts the most popular of each fcntl operation/flag into asm-generic/fcntl.h and cleans up the arch files. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-07[PATCH] Clean up the open flagsStephen Rothwell
This patch puts the most popular of each open flag into asm-generic/fcntl.h and cleans up the arch files. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-07[PATCH] Create asm-generic/fcntl.hStephen Rothwell
This set of patches creates asm-generic/fcntl.h and consolidates as much as possible from the asm-*/fcntl.h files into it. This patch just gathers all the identical bits of the asm-*/fcntl.h files into asm-generic/fcntl.h. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Yoichi Yuasa <yuasa@hh.iij4u.or.jp> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-07[PATCH] remove verify_area(): remove verify_area() from various uaccess.h ↵Jesper Juhl
headers Remove the deprecated (and unused) verify_area() from various uaccess.h headers. Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-07[PATCH] remove asm-*/hdreg.hChristoph Hellwig
unused and useless.. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-07[PATCH] auxiliary vector cleanupsH. J. Lu
The size of auxiliary vector is fixed at 42 in linux/sched.h. But it isn't very obvious when looking at linux/elf.h. This patch adds AT_VECTOR_SIZE so that we can change it if necessary when a new vector is added. Because of include file ordering problems, doing this necessitated the extraction of the AT_* symbols into a standalone header file. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-07[PATCH] FUTEX_WAKE_OP: pthread_cond_signal() speedupJakub Jelinek
ATM pthread_cond_signal is unnecessarily slow, because it wakes one waiter (which at least on UP usually means an immediate context switch to one of the waiter threads). This waiter wakes up and after a few instructions it attempts to acquire the cv internal lock, but that lock is still held by the thread calling pthread_cond_signal. So it goes to sleep and eventually the signalling thread is scheduled in, unlocks the internal lock and wakes the waiter again. Now, before 2003-09-21 NPTL was using FUTEX_REQUEUE in pthread_cond_signal to avoid this performance issue, but it was removed when locks were redesigned to the 3 state scheme (unlocked, locked uncontended, locked contended). Following scenario shows why simply using FUTEX_REQUEUE in pthread_cond_signal together with using lll_mutex_unlock_force in place of lll_mutex_unlock is not enough and probably why it has been disabled at that time: The number is value in cv->__data.__lock. thr1 thr2 thr3 0 pthread_cond_wait 1 lll_mutex_lock (cv->__data.__lock) 0 lll_mutex_unlock (cv->__data.__lock) 0 lll_futex_wait (&cv->__data.__futex, futexval) 0 pthread_cond_signal 1 lll_mutex_lock (cv->__data.__lock) 1 pthread_cond_signal 2 lll_mutex_lock (cv->__data.__lock) 2 lll_futex_wait (&cv->__data.__lock, 2) 2 lll_futex_requeue (&cv->__data.__futex, 0, 1, &cv->__data.__lock) # FUTEX_REQUEUE, not FUTEX_CMP_REQUEUE 2 lll_mutex_unlock_force (cv->__data.__lock) 0 cv->__data.__lock = 0 0 lll_futex_wake (&cv->__data.__lock, 1) 1 lll_mutex_lock (cv->__data.__lock) 0 lll_mutex_unlock (cv->__data.__lock) # Here, lll_mutex_unlock doesn't know there are threads waiting # on the internal cv's lock Now, I believe it is possible to use FUTEX_REQUEUE in pthread_cond_signal, but it will cost us not one, but 2 extra syscalls and, what's worse, one of these extra syscalls will be done for every single waiting loop in pthread_cond_*wait. We would need to use lll_mutex_unlock_force in pthread_cond_signal after requeue and lll_mutex_cond_lock in pthread_cond_*wait after lll_futex_wait. Another alternative is to do the unlocking pthread_cond_signal needs to do (the lock can't be unlocked before lll_futex_wake, as that is racy) in the kernel. I have implemented both variants, futex-requeue-glibc.patch is the first one and futex-wake_op{,-glibc}.patch is the unlocking inside of the kernel. The kernel interface allows userland to specify how exactly an unlocking operation should look like (some atomic arithmetic operation with optional constant argument and comparison of the previous futex value with another constant). It has been implemented just for ppc*, x86_64 and i?86, for other architectures I'm including just a stub header which can be used as a starting point by maintainers to write support for their arches and ATM will just return -ENOSYS for FUTEX_WAKE_OP. The requeue patch has been (lightly) tested just on x86_64, the wake_op patch on ppc64 kernel running 32-bit and 64-bit NPTL and x86_64 kernel running 32-bit and 64-bit NPTL. With the following benchmark on UP x86-64 I get: for i in nptl-orig nptl-requeue nptl-wake_op; do echo time elf/ld.so --library-path .:$i /tmp/bench; \ for j in 1 2; do echo ( time elf/ld.so --library-path .:$i /tmp/bench ) 2>&1; done; done time elf/ld.so --library-path .:nptl-orig /tmp/bench real 0m0.655s user 0m0.253s sys 0m0.403s real 0m0.657s user 0m0.269s sys 0m0.388s time elf/ld.so --library-path .:nptl-requeue /tmp/bench real 0m0.496s user 0m0.225s sys 0m0.271s real 0m0.531s user 0m0.242s sys 0m0.288s time elf/ld.so --library-path .:nptl-wake_op /tmp/bench real 0m0.380s user 0m0.176s sys 0m0.204s real 0m0.382s user 0m0.175s sys 0m0.207s The benchmark is at: http://sourceware.org/ml/libc-alpha/2005-03/txt00001.txt Older futex-requeue-glibc.patch version is at: http://sourceware.org/ml/libc-alpha/2005-03/txt00002.txt Older futex-wake_op-glibc.patch version is at: http://sourceware.org/ml/libc-alpha/2005-03/txt00003.txt Will post a new version (just x86-64 fixes so that the patch applies against pthread_cond_signal.S) to libc-hacker ml soon. Attached is the kernel FUTEX_WAKE_OP patch as well as a simple-minded testcase that will not test the atomicity of the operation, but at least check if the threads that should have been woken up are woken up and whether the arithmetic operation in the kernel gave the expected results. Acked-by: Ingo Molnar <mingo@redhat.com> Cc: Ulrich Drepper <drepper@redhat.com> Cc: Jamie Lokier <jamie@shareable.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Yoichi Yuasa <yuasa@hh.iij4u.or.jp> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-05[PATCH] sab: consolidate kmem_bufctl_tKyle Moffett
This is used only in slab.c and each architecture gets to define whcih underlying type is to be used. Seems a bit silly - move it to slab.c and use the same type for all architectures: unsigned int. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-05[PATCH] mm: consolidate get_orderStephen Rothwell
Someone mentioned that almost all the architectures used basically the same implementation of get_order. This patch consolidates them into asm-generic/page.h and includes that in the appropriate places. The exceptions are ia64 and ppc which have their own (presumably optimised) versions. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-08-29[NET]: Introduce SO_{SND,RCV}BUFFORCE socket optionsPatrick McHardy
Allows overriding of sysctl_{wmem,rmrm}_max Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-07-26[PATCH] Add emergency_restart()Eric W. Biederman
When the kernel is working well and we want to restart cleanly kernel_restart is the function to use. But in many instances the kernel wants to reboot when thing are expected to be working very badly such as from panic or a software watchdog handler. This patch adds the function emergency_restart() so that callers can be clear what semantics they expect when calling restart. emergency_restart() is expected to be callable from interrupt context and possibly reliable in even more trying circumstances. This is an initial generic implementation for all architectures. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-29[PATCH] Serial: Split 8250 port table (part 2)Russell King
Remove legacy ISA serial ports for Accent, Boca, Fourport, Hub6 and MCA from the architecture specific serial.h include. The only ports which remain in asm-*/serial.h are the platform specific entries. These should really be converted by platform maintainers to use a platform device, such as can be found in arch/arm/mach-footbridge/isa.c Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-06-23[PATCH] streamline preempt_count type across archsJesper Juhl
The preempt_count member of struct thread_info is currently either defined as int, unsigned int or __s32 depending on arch. This patch makes the type of preempt_count an int on all archs. Having preempt_count be an unsigned type prevents the catching of preempt_count < 0 bugs, and using int on some archs and __s32 on others is not exactely "neat" - much nicer when it's just int all over. A previous version of this patch was already ACK'ed by Robert Love, and the only change in this version of the patch compared to the one he ACK'ed is that this one also makes sure the preempt_count member is consistently commented. Signed-off-by: Jesper Juhl <juhl-lkml@dif.dk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>