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: David Daney <ddaney@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/4249/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
David Daney 2012-08-16 11:15:22 -07:00 committed by Ralf Baechle
parent a7911a8fd1
commit f59a2d22a0

View File

@ -26,17 +26,17 @@ void pgd_init(unsigned long page)
p = (unsigned long *) page;
end = p + PTRS_PER_PGD;
while (p < end) {
do {
p[0] = entry;
p[1] = entry;
p[2] = entry;
p[3] = entry;
p[4] = entry;
p[5] = entry;
p[6] = entry;
p[7] = entry;
p += 8;
}
p[-3] = entry;
p[-2] = entry;
p[-1] = entry;
} while (p != end);
}
#ifndef __PAGETABLE_PMD_FOLDED
@ -47,17 +47,17 @@ void pmd_init(unsigned long addr, unsigned long pagetable)
p = (unsigned long *) addr;
end = p + PTRS_PER_PMD;
while (p < end) {
do {
p[0] = pagetable;
p[1] = pagetable;
p[2] = pagetable;
p[3] = pagetable;
p[4] = pagetable;
p[5] = pagetable;
p[6] = pagetable;
p[7] = pagetable;
p += 8;
}
p[-3] = pagetable;
p[-2] = pagetable;
p[-1] = pagetable;
} while (p != end);
}
#endif