• Ingo Molnar's avatar
    [PATCH] spinlock consolidation · fb1c8f93
    Ingo Molnar authored
    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
     - 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 <grundler@parisc-linux.org>
      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" <tony.luck@intel.com>
       ia64 fix
    Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
    Signed-off-by: default avatarArjan van de Ven <arjanv@infradead.org>
    Signed-off-by: default avatarGrant Grundler <grundler@parisc-linux.org>
    Cc: Matthew Wilcox <willy@debian.org>
    Signed-off-by: default avatarHirokazu Takata <takata@linux-m32r.org>
    Signed-off-by: default avatarMikael Pettersson <mikpe@csd.uu.se>
    Signed-off-by: default avatarBenoit Boissinot <benoit.boissinot@ens-lyon.org>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
kernel_lock.c 4.48 KB