On 06/15/2016 01:45 PM, Peter Zijlstra wrote:
On Tue, Jun 14, 2016 at 06:48:08PM -0400, Waiman Long wrote:+++ b/arch/alpha/include/asm/rwsem.h @@ -17,9 +17,9 @@ #define RWSEM_UNLOCKED_VALUE 0x0000000000000000L #define RWSEM_ACTIVE_BIAS 0x0000000000000001L #define RWSEM_ACTIVE_MASK 0x00000000ffffffffL -#define RWSEM_WAITING_BIAS (-0x0000000100000000L) +#define RWSEM_WAITING_BIAS 0xc000000000000000L #define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS -#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS) +#define RWSEM_ACTIVE_WRITE_BIAS (-RWSEM_ACTIVE_MASK) +++ b/arch/ia64/include/asm/rwsem.h @@ -30,9 +30,9 @@ #define RWSEM_UNLOCKED_VALUE __IA64_UL_CONST(0x0000000000000000) #define RWSEM_ACTIVE_BIAS (1L) #define RWSEM_ACTIVE_MASK (0xffffffffL) -#define RWSEM_WAITING_BIAS (-0x100000000L) +#define RWSEM_WAITING_BIAS (-(1L<< 62)) #define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS -#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS) +#define RWSEM_ACTIVE_WRITE_BIAS (-RWSEM_ACTIVE_MASK) +++ b/arch/s390/include/asm/rwsem.h @@ -42,9 +42,9 @@ #define RWSEM_UNLOCKED_VALUE 0x0000000000000000L #define RWSEM_ACTIVE_BIAS 0x0000000000000001L #define RWSEM_ACTIVE_MASK 0x00000000ffffffffL -#define RWSEM_WAITING_BIAS (-0x0000000100000000L) +#define RWSEM_WAITING_BIAS 0xc000000000000000L #define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS -#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS) +#define RWSEM_ACTIVE_WRITE_BIAS (-RWSEM_ACTIVE_MASK) +++ b/arch/x86/include/asm/rwsem.h @@ -41,21 +41,23 @@ /* * The bias values and the counter type limits the number of - * potential readers/writers to 32767 for 32 bits and 2147483647 - * for 64 bits. + * potential writers to 16383 for 32 bits and 1073741823 for 64 bits. + * The combined readers and writers can go up to 65534 for 32-bits and + * 4294967294 for 64-bits. */ #ifdef CONFIG_X86_64 # define RWSEM_ACTIVE_MASK 0xffffffffL +# define RWSEM_WAITING_BIAS (-(1L<< 62)) #else # define RWSEM_ACTIVE_MASK 0x0000ffffL +# define RWSEM_WAITING_BIAS (-(1L<< 30)) #endif #define RWSEM_UNLOCKED_VALUE 0x00000000L #define RWSEM_ACTIVE_BIAS 0x00000001L -#define RWSEM_WAITING_BIAS (-RWSEM_ACTIVE_MASK-1) #define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS -#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS) +#define RWSEM_ACTIVE_WRITE_BIAS (-RWSEM_ACTIVE_MASK) +++ b/include/asm-generic/rwsem.h @@ -18,15 +18,16 @@ */ #ifdef CONFIG_64BIT # define RWSEM_ACTIVE_MASK 0xffffffffL +# define RWSEM_WAITING_BIAS (-(1L<< 62)) #else # define RWSEM_ACTIVE_MASK 0x0000ffffL +# define RWSEM_WAITING_BIAS (-(1L<< 30)) #endif #define RWSEM_UNLOCKED_VALUE 0x00000000L #define RWSEM_ACTIVE_BIAS 0x00000001L -#define RWSEM_WAITING_BIAS (-RWSEM_ACTIVE_MASK-1) #define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS -#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS) +#define RWSEM_ACTIVE_WRITE_BIAS (-RWSEM_ACTIVE_MASK)Can't we collapse all that? They all seem very similar.
Yes, they are actually the same. I think we could extract the macro definitions into asm-generic/rwsem-macros.h, for instance, and make the architecture specific header file include the new generic header.
Cheers, Longman -- To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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