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Date: Mon, 09 Feb 2009 16:39:08 -0500 From: Jeff Mahoney <jeffm@...e.com> To: Kyle McMartin <kyle@...radead.org> Cc: Chuck Ebbert <cebbert@...hat.com>, linux-kernel@...r.kernel.org, Chris Mason <chris.mason@...cle.com>, Ingo Molnar <mingo@...e.hu> Subject: Re: Build failure with latest -git: btrfs on ppc64 -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Kyle McMartin wrote: > On Sat, Feb 07, 2009 at 03:50:39PM -0500, Chuck Ebbert wrote: >> fs/btrfs/locking.c: In function 'btrfs_path_lock_waiting': >> fs/btrfs/locking.c:254: error: implicit declaration of function '__raw_spin_is_contended' >> >> Looks like spin_is_contended() is only available on mips and x86?? >> > > Looks to be if there are other folks in line for the ticket lock. > > Arguably this should probably be something silly in spinlock.h like, > > #ifndef __raw_spin_is_contended > # define spin_is_contended (0) > #else > # define spin_is_contended(x) __raw_spin_is_contended((x)) > #endif > > or something since in theory anybody has a chance of acquiring it next > (well, lies because caches bias, but there's no waiters at least.) > > Either that, or we just define it to be spin_is_locked if the assumption > is that the lock will continue to be locked... I fixed it in my tree using the following patch. From: Jeff Mahoney <jeffm@...e.com> Subject: [PATCH] spin_is_contended Kconfig fixes include/linux/spinlock.h contains the following chunk: #ifdef CONFIG_GENERIC_LOCKBREAK #define spin_is_contended(lock) ((lock)->break_lock) #else #define spin_is_contended(lock) __raw_spin_is_contended(&(lock)->raw_lock) #endif __raw_spin_is_contended() is only implemented on mips and x86. Prior to a recent commit against btrfs, spin_needbreak was the only user of spin_is_contended, and it returns 0 when !CONFIG_PREEMPT. The architecture Kconfigs reflect that, depending on PREEMPT to enable GENERIC_LOCKBREAK. With the btrfs changes, this is causing build failures on anything !x86 (and mips, but I don't build on mips). Now that there is another user of spin_is_contended, the PREEMPT dependency is obsolete. This removes the dependency. This patch also adds GENERIC_LOCKBREAK entries to architectures that didn't have it and offer SMP support. The removal of the SPARC64 dependency isn't an oversight - SMP is supported for 32-bit sparc, so it would run into the same problem. Signed-off-by: Jeff Mahoney <jeffm@...e.com> - --- arch/alpha/Kconfig | 5 +++++ arch/arm/Kconfig | 2 +- arch/blackfin/Kconfig | 5 +++++ arch/ia64/Kconfig | 2 +- arch/m32r/Kconfig | 2 +- arch/parisc/Kconfig | 2 +- arch/powerpc/Kconfig | 2 +- arch/s390/Kconfig | 2 +- arch/sh/Kconfig | 7 ++++++- arch/sparc/Kconfig | 2 +- 10 files changed, 23 insertions(+), 8 deletions(-) - --- a/arch/alpha/Kconfig +++ b/arch/alpha/Kconfig @@ -25,6 +25,11 @@ config MMU config RWSEM_GENERIC_SPINLOCK bool +config GENERIC_LOCKBREAK + bool + default y + depends on SMP + config RWSEM_XCHGADD_ALGORITHM bool default y - --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -115,7 +115,7 @@ config GENERIC_IRQ_PROBE config GENERIC_LOCKBREAK bool default y - - depends on SMP && PREEMPT + depends on SMP config RWSEM_GENERIC_SPINLOCK bool - --- a/arch/blackfin/Kconfig +++ b/arch/blackfin/Kconfig @@ -21,6 +21,11 @@ config RWSEM_XCHGADD_ALGORITHM bool default n +config GENERIC_LOCKBREAK + bool + default y + depends on SMP + config BLACKFIN bool default y - --- a/arch/ia64/Kconfig +++ b/arch/ia64/Kconfig @@ -58,7 +58,7 @@ config IOMMU_HELPER config GENERIC_LOCKBREAK bool default y - - depends on SMP && PREEMPT + depends on SMP config RWSEM_XCHGADD_ALGORITHM bool - --- a/arch/m32r/Kconfig +++ b/arch/m32r/Kconfig @@ -243,7 +243,7 @@ config IRAM_SIZE config GENERIC_LOCKBREAK bool default y - - depends on SMP && PREEMPT + depends on SMP config RWSEM_GENERIC_SPINLOCK bool - --- a/arch/parisc/Kconfig +++ b/arch/parisc/Kconfig @@ -27,7 +27,7 @@ config STACK_GROWSUP config GENERIC_LOCKBREAK bool default y - - depends on SMP && PREEMPT + depends on SMP config RWSEM_GENERIC_SPINLOCK def_bool y - --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -75,7 +75,7 @@ config RWSEM_XCHGADD_ALGORITHM config GENERIC_LOCKBREAK bool default y - - depends on SMP && PREEMPT + depends on SMP config ARCH_HAS_ILOG2_U32 bool - --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -63,7 +63,7 @@ config NO_DMA config GENERIC_LOCKBREAK bool default y - - depends on SMP && PREEMPT + depends on SMP config PGSTE bool - --- a/arch/sh/Kconfig +++ b/arch/sh/Kconfig @@ -43,6 +43,11 @@ config RWSEM_GENERIC_SPINLOCK config RWSEM_XCHGADD_ALGORITHM bool +config GENERIC_LOCKBREAK + bool + default y + depends on SMP + config GENERIC_BUG def_bool y depends on BUG && SUPERH32 @@ -82,7 +87,7 @@ config GENERIC_CLOCKEVENTS_BROADCAST config GENERIC_LOCKBREAK def_bool y - - depends on SMP && PREEMPT + depends on SMP config SYS_SUPPORTS_PM bool - --- a/arch/sparc/Kconfig +++ b/arch/sparc/Kconfig @@ -298,7 +298,7 @@ config US3_MC config GENERIC_LOCKBREAK bool default y - - depends on SPARC64 && SMP && PREEMPT + depends on SMP choice prompt "SPARC64 Huge TLB Page Size" - -- Jeff Mahoney SUSE Labs -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org iEYEARECAAYFAkmQonwACgkQLPWxlyuTD7JPyQCghVJ0vgGlCxAbKZQMPaJxrIYZ ePYAoIbujOBBnc0wqgn2bG+5KB11g8HL =7r7Q -----END PGP SIGNATURE----- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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