17 Jun, 2009

1 commit

  • _atomic_dec_and_lock() should not unconditionally take the lock before
    calling atomic_dec_and_test() in the UP case. For consistency reasons it
    should behave exactly like in the SMP case.

    Besides that this works around the problem that with CONFIG_DEBUG_SPINLOCK
    this spins in __spin_lock_debug() if the lock is already taken even if the
    counter doesn't drop to 0.

    Signed-off-by: Jan Blunck
    Acked-by: Paul E. McKenney
    Acked-by: Nick Piggin
    Cc: Valerie Aurora
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Jan Blunck
     

09 Jan, 2006

1 commit


15 Sep, 2005

1 commit

  • Several implementations were essentialy a common piece of C code using
    the cmpxchg() macro. Put the implementation in one spot that everyone
    can share, and convert sparc64 over to using this.

    Alpha is the lone arch-specific implementation, which codes up a
    special fast path for the common case in order to avoid GP reloading
    which a pure C version would require.

    Signed-off-by: David S. Miller

    David S. Miller
     

11 Sep, 2005

1 commit

  • This patch (written by me and also containing many suggestions of Arjan van
    de Ven) does a major cleanup of the spinlock code. It does the following
    things:

    - consolidates and enhances the spinlock/rwlock debugging code

    - simplifies the asm/spinlock.h files

    - encapsulates the raw spinlock type and moves generic spinlock
    features (such as ->break_lock) into the generic code.

    - cleans up the spinlock code hierarchy to get rid of the spaghetti.

    Most notably there's now only a single variant of the debugging code,
    located in lib/spinlock_debug.c. (previously we had one SMP debugging
    variant per architecture, plus a separate generic one for UP builds)

    Also, i've enhanced the rwlock debugging facility, it will now track
    write-owners. There is new spinlock-owner/CPU-tracking on SMP builds too.
    All locks have lockup detection now, which will work for both soft and hard
    spin/rwlock lockups.

    The arch-level include files now only contain the minimally necessary
    subset of the spinlock code - all the rest that can be generalized now
    lives in the generic headers:

    include/asm-i386/spinlock_types.h | 16
    include/asm-x86_64/spinlock_types.h | 16

    I have also split up the various spinlock variants into separate files,
    making it easier to see which does what. The new layout is:

    SMP | UP
    ----------------------------|-----------------------------------
    asm/spinlock_types_smp.h | linux/spinlock_types_up.h
    linux/spinlock_types.h | linux/spinlock_types.h
    asm/spinlock_smp.h | linux/spinlock_up.h
    linux/spinlock_api_smp.h | linux/spinlock_api_up.h
    linux/spinlock.h | linux/spinlock.h

    /*
    * here's the role of the various spinlock/rwlock related include files:
    *
    * on SMP builds:
    *
    * asm/spinlock_types.h: contains the raw_spinlock_t/raw_rwlock_t and the
    * initializers
    *
    * linux/spinlock_types.h:
    * defines the generic type and initializers
    *
    * asm/spinlock.h: contains the __raw_spin_*()/etc. lowlevel
    * implementations, mostly inline assembly code
    *
    * (also included on UP-debug builds:)
    *
    * linux/spinlock_api_smp.h:
    * contains the prototypes for the _spin_*() APIs.
    *
    * linux/spinlock.h: builds the final spin_*() APIs.
    *
    * on UP builds:
    *
    * linux/spinlock_type_up.h:
    * contains the generic, simplified UP spinlock type.
    * (which is an empty structure on non-debug builds)
    *
    * linux/spinlock_types.h:
    * defines the generic type and initializers
    *
    * linux/spinlock_up.h:
    * contains the __raw_spin_*()/etc. version of UP
    * builds. (which are NOPs on non-debug, non-preempt
    * builds)
    *
    * (included on UP-non-debug builds:)
    *
    * linux/spinlock_api_up.h:
    * builds the _spin_*() APIs.
    *
    * linux/spinlock.h: builds the final spin_*() APIs.
    */

    All SMP and UP architectures are converted by this patch.

    arm, i386, ia64, ppc, ppc64, s390/s390x, x64 was build-tested via
    crosscompilers. m32r, mips, sh, sparc, have not been tested yet, but should
    be mostly fine.

    From: Grant Grundler

    Booted and lightly tested on a500-44 (64-bit, SMP kernel, dual CPU).
    Builds 32-bit SMP kernel (not booted or tested). I did not try to build
    non-SMP kernels. That should be trivial to fix up later if necessary.

    I converted bit ops atomic_hash lock to raw_spinlock_t. Doing so avoids
    some ugly nesting of linux/*.h and asm/*.h files. Those particular locks
    are well tested and contained entirely inside arch specific code. I do NOT
    expect any new issues to arise with them.

    If someone does ever need to use debug/metrics with them, then they will
    need to unravel this hairball between spinlocks, atomic ops, and bit ops
    that exist only because parisc has exactly one atomic instruction: LDCW
    (load and clear word).

    From: "Luck, Tony"

    ia64 fix

    Signed-off-by: Ingo Molnar
    Signed-off-by: Arjan van de Ven
    Signed-off-by: Grant Grundler
    Cc: Matthew Wilcox
    Signed-off-by: Hirokazu Takata
    Signed-off-by: Mikael Pettersson
    Signed-off-by: Benoit Boissinot
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Ingo Molnar
     

17 Apr, 2005

1 commit

  • Initial git repository build. I'm not bothering with the full history,
    even though we have it. We can create a separate "historical" git
    archive of that later if we want to, and in the meantime it's about
    3.2GB when imported into git - space that would just make the early
    git days unnecessarily complicated, when we don't have a lot of good
    infrastructure for it.

    Let it rip!

    Linus Torvalds