[PATCH] rw_semaphores, optimisations

From: D.W.Howells (dhowells@astarte.free-online.co.uk)
Date: Sat Apr 21 2001 - 19:27:20 EST

This patch (made against linux-2.4.4-pre6) makes a number of changes to the
rwsem implementation:

 (1) Fixes a subtle contention bug between up_write and the down_* functions.

 (2) Optimises the i386 fastpath implementation and changed the slowpath
     implementation to aid it.
     - The arch/i386/lib/rwsem.c is now gone.
     - Better inline asm constraints have been applied.

 (3) Changed the sparc64 fastpath implementation to use revised slowpath
     interface.
     [Dave Miller: can you check this please]

 (4) Makes the generic spinlock implementation non-inline.
     - lib/rwsem.c has been duplicated to lib/rwsem-spinlock.c and a
       slightly different algorithm has been created. This one is simpler
       since it does not have to use atomic operations on the counters as
       all accesses to them are governed by a blanket spinlock.

David


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This archive was generated by hypermail 2b29 : Mon Apr 23 2001 - 21:00:41 EST