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* [SPARC]: Handle UNWIND_INFO properly.David S. Miller2006-05-12
| | | | | | | | | For sparc32 we need R_SPARC_UA32 relocation support, for sparc64 we need the handle R_SPARC_DISP32 relocations. Based upon reports and initial patch by Martin Habets. Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC]: show device name in /proc/dvma_mapMartin Habets2006-05-08
| | | | | | | | This patch will set the device name in a resource, which will be shown in /proc/dvma_map. Signed-off-by: Martin Habets <errandir_news@mph.eclipse.co.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC]: Remove duplicate symbol exportsMartin Habets2006-05-08
| | | | | | | | | | | | | | | | | | This patch resolves the following build warnings seen in 2.6.17-rc3: WARNING: vmlinux: 'sys_close' exported twice. Previous export was in vmlinux WARNING: vmlinux: 'memchr' exported twice. Previous export was in vmlinux WARNING: vmlinux: 'strstr' exported twice. Previous export was in vmlinux WARNING: vmlinux: 'strnlen' exported twice. Previous export was in vmlinux WARNING: vmlinux: 'strrchr' exported twice. Previous export was in vmlinux WARNING: vmlinux: 'strchr' exported twice. Previous export was in vmlinux WARNING: vmlinux: 'strcmp' exported twice. Previous export was in vmlinux WARNING: vmlinux: 'strncat' exported twice. Previous export was in vmlinux WARNING: vmlinux: 'strcat' exported twice. Previous export was in vmlinux WARNING: vmlinux: 'strncpy' exported twice. Previous export was in vmlinux WARNING: vmlinux: 'strcpy' exported twice. Previous export was in vmlinux Signed-off-by: Martin Habets <errandir_news@mph.eclipse.co.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC]: Hook up vmsplice into syscall tables.David S. Miller2006-05-03
| | | | Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC]: Hook up sys_tee() into syscall tables.David S. Miller2006-04-14
| | | | Signed-off-by: David S. Miller <davem@davemloft.net>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuildLinus Torvalds2006-04-11
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild: kconfig: fix typo in change count initialization kconfig: recenter menuconfig kconfig: revert conf behaviour change kconfig: fix default value for choice input kbuild: fix NULL dereference in scripts/mod/modpost.c kbuild: fix mode of checkstack.pl and other files. kbuild: rebuild initramfs if content of initramfs changes kbuild: properly pass options to hostcc when doing make O=.. kbuild: modules_install for external modules must not remove existing modules kbuild: fix make dir/ ver_linux: don't print reiser4progs version if none found kbuild: mips: fix sed regexp to generate asm-offset.h kbuild: fix building single targets with make O=.. single-target kbuild: use relative path to -I kbuild: fix unneeded rebuilds in drivers/net/chelsio after moving source tree kbuild: fix unneeded rebuilds in drivers/media/video after moving source tree kbuild: fix garbled text in modules.txt
| * kbuild: use relative path to -ISam Ravnborg2006-04-04
| | | | | | | | | | | | | | | | | | Using a relative path has the advantage that when the kernel source tree is moved the relevant .o files will not be rebuild just because the path to the kernel src has changed. This also got rid of a user of TOPDIR - which has been deprecated for a long time now. Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
* | [PATCH] No arch-specific strpbrk implementationsKyle McMartin2006-04-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While cleaning up parisc_ksyms.c earlier, I noticed that strpbrk wasn't being exported from lib/string.c. Investigating further, I noticed a changeset that removed its export and added it to _ksyms.c on a few more architectures. The justification was that "other arches do it." I think this is wrong, since no architecture currently defines __HAVE_ARCH_STRPBRK, there's no reason for any of them to be exporting it themselves. Therefore, consolidate the export to lib/string.c. Signed-off-by: Kyle McMartin <kyle@parisc-linux.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* | [PATCH] for_each_possible_cpu: sparcKAMEZAWA Hiroyuki2006-04-11
|/ | | | | | | | | | | | | | | | | for_each_cpu() actually iterates across all possible CPUs. We've had mistakes in the past where people were using for_each_cpu() where they should have been iterating across only online or present CPUs. This is inefficient and possibly buggy. We're renaming for_each_cpu() to for_each_possible_cpu() to avoid this in the future. This patch replaces for_each_cpu with for_each_possible_cpu. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [SPARC]: Wire up sys_sync_file_range() into syscall tables.David S. Miller2006-04-01
| | | | Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC]: Wire up sys_splice() into the syscall tables.David S. Miller2006-04-01
| | | | Signed-off-by: David S. Miller <davem@davemloft.net>
* [PATCH] bitops: sparc: use generic bitopsAkinobu Mita2006-03-26
| | | | | | | | | | | | | | | | | | | | - remove __{,test_and_}{set,clear,change}_bit() and test_bit() - remove ffz() - remove __ffs() - remove sched_find_first_bit() - remove ffs() - remove generic_fls() - remove generic_fls64() - remove generic_hweight{32,16,8}() - remove find_{next,first}{,_zero}_bit() - remove ext2_{set,clear,test,find_first_zero,find_next_zero}_bit() - remove ext2_{set,clear}_bit_atomic() - remove minix_{test,set,test_and_clear,test,find_first_zero}_bit() Signed-off-by: Akinobu Mita <mita@miraclelinux.com> Cc: William Lee Irwin III <wli@holomorphy.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [SPARC]: Try to start getting SMP back into shape.Bob Breuer2006-03-24
| | | | | | | | | | | | | | | | | Todo items: - IRQ_INPROGRESS flag - use sparc64 irq buckets, or generic irq_desc? - sun4d - re-indent large chunks of sun4m_smp.c - some places assume sequential cpu numbering (i.e. 0,1 instead of 0,2) Last I checked (with 2.6.14), random programs segfault with dual HyperSPARC. And with SuperSPARC II's, it seems stable but will eventually die from a write lock error (wrong lock owner or something). I haven't tried the HyperSPARC + highmem combination recently, so that may still be a problem. Signed-off-by: David S. Miller <davem@davemloft.net>
* [PATCH] more for_each_cpu() conversionsAndrew Morton2006-03-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we stop allocating percpu memory for not-possible CPUs we must not touch the percpu data for not-possible CPUs at all. The correct way of doing this is to test cpu_possible() or to use for_each_cpu(). This patch is a kernel-wide sweep of all instances of NR_CPUS. I found very few instances of this bug, if any. But the patch converts lots of open-coded test to use the preferred helper macros. Cc: Mikael Starvik <starvik@axis.com> Cc: David Howells <dhowells@redhat.com> Acked-by: Kyle McMartin <kyle@parisc-linux.org> Cc: Anton Blanchard <anton@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Andi Kleen <ak@muc.de> Cc: Christian Zankel <chris@zankel.net> Cc: Philippe Elie <phil.el@wanadoo.fr> Cc: Nathan Scott <nathans@sgi.com> Cc: Jens Axboe <axboe@suse.de> Cc: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6Linus Torvalds2006-03-22
|\ | | | | | | | | | | * master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6: [SPARC64]: Add a secondary TSB for hugepage mappings. [SPARC]: Respect vm_page_prot in io_remap_page_range().
| * [SPARC]: Respect vm_page_prot in io_remap_page_range().David S. Miller2006-03-22
| | | | | | | | | | | | | | | | | | Make sure the callers do a pgprot_noncached() on vma->vm_page_prot. Pointed out by Hugh Dickens. Signed-off-by: David S. Miller <davem@davemloft.net>
* | [PATCH] remove set_page_count() outside mm/Nick Piggin2006-03-22
|/ | | | | | | | | | | | | set_page_count usage outside mm/ is limited to setting the refcount to 1. Remove set_page_count from outside mm/, and replace those users with init_page_count() and set_page_refcounted(). This allows more debug checking, and tighter control on how code is allowed to play around with page->_count. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [SPARC]: BUG_ON() Conversion in arch/sparc/kernel/ioport.cEric Sesterhenn2006-03-20
| | | | | | | | this changes if() BUG(); constructs to BUG_ON() which is cleaner and can better optimized away Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC]: sys_newfstatat --> sys_fstatat64David S. Miller2006-02-13
| | | | Signed-off-by: David S. Miller <davem@davemloft.net>
* Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6Linus Torvalds2006-02-07
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| * [SPARC]: Wire up sys_unshare().David S. Miller2006-02-07
| | | | | | | | | | | | | | | | Also, the Solaris syscall table is sized differrently, and does not go beyond entry 255, so trim off the excess entries. Signed-off-by: David S. Miller <davem@davemloft.net>
* | [PATCH] restore power-off on sparc32Al Viro2006-02-07
|/ | | | | | Damn you, Eric Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* [SPARC]: Fix compile failures in math-emu.David S. Miller2006-01-30
| | | | | | | | | | | Kill debugging default switch cases in do_one_mathemu(). That case is handled properly already and gcc hates the empty statement that results when the debug code is disabled. Pointed out by kaffe. Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC]: Increase NR_SYSCALLS to 299David S. Miller2006-01-22
| | | | | | To let new syscalls through. Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC]: Add support for *at(), ppoll, and pselect syscalls.David S. Miller2006-01-19
| | | | | | | | | | This also includes by necessity _TIF_RESTORE_SIGMASK support, which actually resulted in a lot of cleanups. The sparc signal handling code is quite a mess and I should clean it up some day. Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC]: change if() BUG(); to BUG_ON in iommu.cEric Sesterhenn2006-01-17
| | | | | | | | | this patch changes if() BUG(); constructs in iommu.c to BUG_ON(); so it gets save to define BUG() and BUG_ON() to nullstatements. Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* [PATCH] sparc: task_stack_page()Al Viro2006-01-12
| | | | | | 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>
* [PATCH] sparc: task_thread_info()Al Viro2006-01-12
| | | | | | 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>
* [PATCH] capable/capability.h (arch/)Randy Dunlap2006-01-11
| | | | | | | | arch: Use <linux/capability.h> where capable() is used. Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] dump_thread() cleanupakpm@osdl.org2006-01-10
| | | | | | | | | | | | | | | | ) From: Adrian Bunk <bunk@stusta.de> - create one common dump_thread() prototype in kernel.h - dump_thread() is only used in fs/binfmt_aout.c and can therefore be removed on all architectures where CONFIG_BINFMT_AOUT is not available Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] tiny: Make *[ug]id16 support optionalMatt Mackall2006-01-08
| | | | | | | | | | | | | | | | | | | Configurable 16-bit UID and friends support This allows turning off the legacy 16 bit UID interfaces on embedded platforms. text data bss dec hex filename 3330172 529036 190556 4049764 3dcb64 vmlinux-baseline 3328268 529040 190556 4047864 3dc3f8 vmlinux From: Adrian Bunk <bunk@stusta.de> UID16 was accidentially disabled for !EMBEDDED. Signed-off-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] use ptrace_get_task_struct in various placesChristoph Hellwig2006-01-08
| | | | | | | | | | | | | | | | The ptrace_get_task_struct() helper that I added as part of the ptrace consolidation is useful in variety of places that currently opencode it. Switch them to the common helpers. Add a ptrace_traceme() helper that needs to be explicitly called, and simplify the ptrace_get_task_struct() interface. We don't need the request argument now, and we return the task_struct directly, using ERR_PTR() for error returns. It's a bit more code in the callers, but we have two sane routines that do one thing well now. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [SPARC]: Use STABS_DEBUG and DWARF_DEBUG macros in vmlinux.lds.SDavid S. Miller2005-12-28
| | | | Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC]: Kill CHILD_MAX.David S. Miller2005-12-23
| | | | | | | | | | | It's definition is wrong (-1 means "no limit" not 999), only the Sparc SunOS/Solaris compat code uses it, so let's just kill it off completely from limits.h and all referencing code. Noticed by Ulrich Drepper. Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC]: introduce a SPARC Kconfig symbolAdrian Bunk2005-12-23
| | | | | | | | | | Introduce a Kconfig symbol SPARC that is defined on both the sparc and sparc64 architectures. This symbol makes some dependencies more readable. Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* [PATCH] arch/sparc/kernel/led.c __user annotationsAl Viro2005-12-15
| | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] sun4c_memerr_reg __iomem annotationsAl Viro2005-12-15
| | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] sparc: NULL noise removal (ebus.c)Al Viro2005-12-15
| | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] sparc/kernel/time: __iomem annotationsAl Viro2005-12-15
| | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] fix iomem annotations in sparc32 pcic codeAl Viro2005-12-15
| | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [SPARC]: block/ needed in final image linkPaul Jackson2005-12-12
| | | | | | | | | | | | | | | With this fix, sparc links vmlinuz again using crosstool. Without this fix, the final link fails missing several dozen dozen symbols, beginning with: kernel/built-in.o(.text+0x6fd0): In function `do_exit': : undefined reference to `exit_io_context' (exit_io_context is defined in block/ll_rw_blk.c). Signed-off-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [SPARC]: atomic_clear_mask build fixPaul Jackson2005-12-12
| | | | | | | | | | | | This fixes one build error introduced in sparc with the patch of Oct 30, resent Nov 4 "[patch 3/5] atomic: atomic_inc_not_zero" I still can't get sparc to build, but at least it gets further after I remove this line. Apparently, this change was agreed to by Andrew and Nick on Nov 14, but everyone thought someone else was doing it. Signed-off-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* [PATCH] sparc: convert IO remapping to VM_PFNMAPDavid S. Miller2005-11-28
| | | | | | Here are the Sparc bits. Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] unpaged: fix sound Bad page statesHugh Dickins2005-11-22
| | | | | | | | | | | | | | | | | | Earlier I unifdefed PageCompound, so that snd_pcm_mmap_control_nopage and others can give out a 0-order component of a higher-order page, which won't be mistakenly freed when zap_pte_range unmaps it. But many Bad page states reported a PG_reserved was freed after all: I had missed that we need to say __GFP_COMP to get compound page behaviour. Some of these higher-order pages are allocated by snd_malloc_pages, some by snd_malloc_dev_pages; or if SBUS, by sbus_alloc_consistent - but that has no gfp arg, so add __GFP_COMP into its sparc32/64 implementations. I'm still rather puzzled that DRM seems not to need a similar change. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] unpaged: VM_UNPAGEDHugh Dickins2005-11-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Although we tend to associate VM_RESERVED with remap_pfn_range, quite a few drivers set VM_RESERVED on areas which are then populated by nopage. The PageReserved removal in 2.6.15-rc1 changed VM_RESERVED not to free pages in zap_pte_range, without changing those drivers not to set it: so their pages just leak away. Let's not change miscellaneous drivers now: introduce VM_UNPAGED at the core, to flag the special areas where the ptes may have no struct page, or if they have then it's not to be touched. Replace most instances of VM_RESERVED in core mm by VM_UNPAGED. Force it on in remap_pfn_range, and the sparc and sparc64 io_remap_pfn_range. Revert addition of VM_RESERVED to powerpc vdso, it's not needed there. Is it needed anywhere? It still governs the mm->reserved_vm statistic, and special vmas not to be merged, and areas not to be core dumped; but could probably be eliminated later (the drivers are probably specifying it because in 2.4 it kept swapout off the vma, but in 2.6 we work from the LRU, which these pages don't get on). Use the VM_SHM slot for VM_UNPAGED, and define VM_SHM to 0: it serves no purpose whatsoever, and should be removed from drivers when we clean up. Signed-off-by: Hugh Dickins <hugh@veritas.com> Acked-by: William Irwin <wli@holomorphy.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] atomic: inc_not_zeroNick Piggin2005-11-13
| | | | | | | | | | | 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>
* [PATCH] atomic: cmpxchgNick Piggin2005-11-13
| | | | | | | | | 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>
* [PATCH] m68k: thread_info header cleanupAl Viro2005-11-13
| | | | | | | | | | | | | | | | | | | | a) in smp_lock.h #include of sched.h and spinlock.h moved under #ifdef CONFIG_LOCK_KERNEL. b) interrupt.h now explicitly pulls sched.h (not via smp_lock.h from hardirq.h as it used to) c) in three more places we need changes to compensate for (a) - one place in arch/sparc needs string.h now, hardirq.h needs forward declaration of task_struct and preempt.h needs direct include of thread_info.h. d) thread_info-related helpers in sched.h and thread_info.h put under ifndef __HAVE_THREAD_FUNCTIONS. Obviously safe. Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk> Signed-off-by: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [SPARC]: Use ARRAY_SIZE macroTobias Klauser2005-11-09
| | | | | | | | Use ARRAY_SIZE macro instead of sizeof(x)/sizeof(x[0]) and remove a duplicate of ARRAY_SIZE which is never used anyways. Signed-off-by: Tobias Klauser <tklauser@nuerscht.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
* [PATCH] sched: resched and cpu_idle reworkNick Piggin2005-11-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make some changes to the NEED_RESCHED and POLLING_NRFLAG to reduce confusion, and make their semantics rigid. Improves efficiency of resched_task and some cpu_idle routines. * In resched_task: - TIF_NEED_RESCHED is only cleared with the task's runqueue lock held, and as we hold it during resched_task, then there is no need for an atomic test and set there. The only other time this should be set is when the task's quantum expires, in the timer interrupt - this is protected against because the rq lock is irq-safe. - If TIF_NEED_RESCHED is set, then we don't need to do anything. It won't get unset until the task get's schedule()d off. - If we are running on the same CPU as the task we resched, then set TIF_NEED_RESCHED and no further action is required. - If we are running on another CPU, and TIF_POLLING_NRFLAG is *not* set after TIF_NEED_RESCHED has been set, then we need to send an IPI. Using these rules, we are able to remove the test and set operation in resched_task, and make clear the previously vague semantics of POLLING_NRFLAG. * In idle routines: - Enter cpu_idle with preempt disabled. When the need_resched() condition becomes true, explicitly call schedule(). This makes things a bit clearer (IMO), but haven't updated all architectures yet. - Many do a test and clear of TIF_NEED_RESCHED for some reason. According to the resched_task rules, this isn't needed (and actually breaks the assumption that TIF_NEED_RESCHED is only cleared with the runqueue lock held). So remove that. Generally one less locked memory op when switching to the idle thread. - Many idle routines clear TIF_POLLING_NRFLAG, and only set it in the inner most polling idle loops. The above resched_task semantics allow it to be set until before the last time need_resched() is checked before going into a halt requiring interrupt wakeup. Many idle routines simply never enter such a halt, and so POLLING_NRFLAG can be always left set, completely eliminating resched IPIs when rescheduling the idle task. POLLING_NRFLAG width can be increased, to reduce the chance of resched IPIs. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Con Kolivas <kernel@kolivas.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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