Messages in this thread | | | Date | Mon, 6 Feb 2017 06:49:02 -0800 | From | Matthew Wilcox <> | Subject | memfill |
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[adding linux-arch to see if anyone there wants to do an optimised version of memfill for their CPU]
On Mon, Feb 06, 2017 at 12:16:44AM +0900, Minchan Kim wrote: > +static inline void zram_fill_page(char *ptr, unsigned long len, > + unsigned long value) > +{ > + int i; > + unsigned long *page = (unsigned long *)ptr; > + > + WARN_ON_ONCE(!IS_ALIGNED(len, sizeof(unsigned long))); > + > + if (likely(value == 0)) { > + memset(ptr, 0, len); > + } else { > + for (i = 0; i < len / sizeof(*page); i++) > + page[i] = value; > + } > +}
I would suggest:
#ifndef __HAVE_ARCH_MEMFILL /** * memfill - Fill a region of memory with the given value * @s: Pointer to the start of the region. * @v: The word to fill the region with. * @n: The size of the region. * * Differs from memset() in that it fills with an unsigned long instead of * a byte. The pointer and the size must be aligned to unsigned long. */ void memfill(unsigned long *s, unsigned long v, size_t n) { WARN_ON_ONCE(!IS_ALIGNED(n, sizeof(v)));
if (likely(v == 0)) { memset(s, 0, n); } else { while (n) { *s++ = v; n -= sizeof(v); } } } EXPORT_SYMBOL(memfill); #endif
(I would also suggest this move to lib/string.c and architectures be given the opportunity to provide an optimised version of memfill).
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