kernel/git/stable/linux.git/include/asm-m68k/futex.h, branch master

m68k,m68knommu: merge header files

2009-01-16T11:58:10+00:00

Merge header files for m68k and m68knommu to the single location: arch/m68k/include/asm The majority of this patch was the result of the script that is included in the changelog below. The script was originally written by Arnd Bergman and exten by me to cover a few more files. When the header files differed the script uses the following: The original m68k file is named _mm.h [mm for memory manager] The m68knommu file is named _no.h [no for no memory manager] The files uses the following include guard: This include gaurd works as the m68knommu toolchain set the __uClinux__ symbol - so this should work in userspace too. Merging the header files for m68k and m68knommu exposes the (unexpected?) ABI differences thus it is easier to actually identify these and thus to fix them. The commit has been build tested with both a m68k and a m68knommu toolchain - with success. The commit has also been tested with "make headers_check" and this patch fixes make headers_check for m68knommu. The script used: TARGET=arch/m68k/include/asm SOURCE=arch/m68knommu/include/asm INCLUDE="cachectl.h errno.h fcntl.h hwtest.h ioctls.h ipcbuf.h \ linkage.h math-emu.h md.h mman.h movs.h msgbuf.h openprom.h \ oplib.h poll.h posix_types.h resource.h rtc.h sembuf.h shmbuf.h \ shm.h shmparam.h socket.h sockios.h spinlock.h statfs.h stat.h \ termbits.h termios.h tlb.h types.h user.h" EQUAL="auxvec.h cputime.h device.h emergency-restart.h futex.h \ ioctl.h irq_regs.h kdebug.h local.h mutex.h percpu.h \ sections.h topology.h" NOMUUFILES="anchor.h bootstd.h coldfire.h commproc.h dbg.h \ elia.h flat.h m5206sim.h m520xsim.h m523xsim.h m5249sim.h \ m5272sim.h m527xsim.h m528xsim.h m5307sim.h m532xsim.h \ m5407sim.h m68360_enet.h m68360.h m68360_pram.h m68360_quicc.h \ m68360_regs.h MC68328.h MC68332.h MC68EZ328.h MC68VZ328.h \ mcfcache.h mcfdma.h mcfmbus.h mcfne.h mcfpci.h mcfpit.h \ mcfsim.h mcfsmc.h mcftimer.h mcfuart.h mcfwdebug.h \ nettel.h quicc_simple.h smp.h" FILES="atomic.h bitops.h bootinfo.h bug.h bugs.h byteorder.h cache.h \ cacheflush.h checksum.h current.h delay.h div64.h \ dma-mapping.h dma.h elf.h entry.h fb.h fpu.h hardirq.h hw_irq.h io.h \ irq.h kmap_types.h machdep.h mc146818rtc.h mmu.h mmu_context.h \ module.h page.h page_offset.h param.h pci.h pgalloc.h \ pgtable.h processor.h ptrace.h scatterlist.h segment.h \ setup.h sigcontext.h siginfo.h signal.h string.h system.h swab.h \ thread_info.h timex.h tlbflush.h traps.h uaccess.h ucontext.h \ unaligned.h unistd.h" mergefile() { BASE=${1%.h} git mv ${SOURCE}/$1 ${TARGET}/${BASE}_no.h git mv ${TARGET}/$1 ${TARGET}/${BASE}_mm.h cat << EOF > ${TARGET}/$1 EOF git add ${TARGET}/$1 } set -e mkdir -p ${TARGET} git mv include/asm-m68k/* ${TARGET} rmdir include/asm-m68k git rm ${SOURCE}/Kbuild for F in $INCLUDE $EQUAL; do git rm ${SOURCE}/$F done for F in $NOMUUFILES; do git mv ${SOURCE}/$F ${TARGET}/$F done for F in $FILES ; do mergefile $F done rmdir arch/m68knommu/include/asm rmdir arch/m68knommu/include Cc: Arnd Bergmann Cc: Geert Uytterhoeven Signed-off-by: Sam Ravnborg Signed-off-by: Greg Ungerer

[PATCH] consolidate asm/futex.h

2006-01-09T04:13:39+00:00

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 Cc: Paolo 'Blaisorblade' Giarrusso Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] Remove unused var from asm/futex.h

2005-09-21T23:16:29+00:00

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 Signed-off-by: Paolo 'Blaisorblade' Giarrusso Signed-off-by: Linus Torvalds

[PATCH] FUTEX_WAKE_OP: pthread_cond_signal() speedup

2005-09-07T23:57:17+00:00

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 Cc: Ulrich Drepper Cc: Jamie Lokier Cc: Rusty Russell Signed-off-by: Yoichi Yuasa Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds