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Commit f59a2d22 authored by David Daney's avatar David Daney Committed by Ralf Baechle
Browse files

MIPS: Optimize pgd_init and pmd_init 



On a dual issue processor GCC generates code that saves a couple of
clock cycles per loop if we rearrange things slightly.  Checking for
p != end saves a SLTU per loop, moving the increment to the middle can
let it dual issue on multi-issue processors.

Signed-off-by: default avatarDavid Daney <ddaney@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/4249/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent a7911a8f

arch/mips/mm/pgtable-64.c

+10 −10
Original line number Original line Diff line number Diff line
@@ -26,17 +26,17 @@ void pgd_init(unsigned long page) 
 	p = (unsigned long *) page;

 	p = (unsigned long *) page;

	end = p + PTRS_PER_PGD;

	end = p + PTRS_PER_PGD;





	while (p < end) {

	do {

		p[0] = entry;

		p[0] = entry;

		p[1] = entry;

		p[1] = entry;

		p[2] = entry;

		p[2] = entry;

		p[3] = entry;

		p[3] = entry;

		p[4] = entry;

		p[4] = entry;

		p[5] = entry;

		p[6] = entry;

		p[7] = entry;

		p += 8;

		p += 8;

	}

		p[-3] = entry;

		p[-2] = entry;

		p[-1] = entry;

	} while (p != end);

}

}





#ifndef __PAGETABLE_PMD_FOLDED

#ifndef __PAGETABLE_PMD_FOLDED
@@ -47,17 +47,17 @@ void pmd_init(unsigned long addr, unsigned long pagetable) 
 	p = (unsigned long *) addr;

 	p = (unsigned long *) addr;

	end = p + PTRS_PER_PMD;

	end = p + PTRS_PER_PMD;





	while (p < end) {

	do {

		p[0] = pagetable;

		p[0] = pagetable;

		p[1] = pagetable;

		p[1] = pagetable;

		p[2] = pagetable;

		p[2] = pagetable;

		p[3] = pagetable;

		p[3] = pagetable;

		p[4] = pagetable;

		p[4] = pagetable;

		p[5] = pagetable;

		p[6] = pagetable;

		p[7] = pagetable;

		p += 8;

		p += 8;

	}

		p[-3] = pagetable;

		p[-2] = pagetable;

		p[-1] = pagetable;

	} while (p != end);

}

}

#endif

#endif