Messages in this thread Patch in this message | | | Date | Sat, 30 Nov 2002 00:40:35 +0100 | From | Petr Vandrovec <> | Subject | [PATCH] Save 8 bytes in __{read,write}_lock_failed... |
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Hi, recent bugreport from Chris Rankin pointed out to me that last jump in both __read_lock_failed and __write_lock_failed uses 4 byte offset, although 1 byte is enough. It happens because of __write_lock_failed is .globl, and so gas emits 4 byte offset + R_386_PC32 relocation (should it? I always thought that only .weak symbols may be overwritten from other file).
Simple patch below makes SMP kernel 8 bytes shorter. Best regards, Petr Vandrovec vandrove@vc.cvut.cz
diff -urdN linux/arch/i386/kernel/semaphore.c linux/arch/i386/kernel/semaphore.c --- linux/arch/i386/kernel/semaphore.c 2002-11-26 19:55:59.000000000 +0000 +++ linux/arch/i386/kernel/semaphore.c 2002-11-29 23:24:50.000000000 +0000 @@ -275,12 +275,13 @@ ".align 4\n" ".globl __write_lock_failed\n" "__write_lock_failed:\n\t" +"0:\n\t" LOCK "addl $" RW_LOCK_BIAS_STR ",(%eax)\n" "1: rep; nop\n\t" "cmpl $" RW_LOCK_BIAS_STR ",(%eax)\n\t" "jne 1b\n\t" LOCK "subl $" RW_LOCK_BIAS_STR ",(%eax)\n\t" - "jnz __write_lock_failed\n\t" + "jnz 0b\n\t" "ret" ); @@ -289,12 +290,13 @@ ".align 4\n" ".globl __read_lock_failed\n" "__read_lock_failed:\n\t" +"0:\n\t" LOCK "incl (%eax)\n" "1: rep; nop\n\t" "cmpl $1,(%eax)\n\t" "js 1b\n\t" LOCK "decl (%eax)\n\t" - "js __read_lock_failed\n\t" + "js 0b\n\t" "ret" ); #endif - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.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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