RE: [PATCH] ext4: convert to DIV_ROUND_UP() in mpage_process_page_bufs()

[David Laight]

...
> On 32-bit platforms --- i386 in particular --- the 64-bit division
> results in an out-of-line call to a helper function that is not
> supplied in the kernel compilation environment, so not only is it
> slower, it Just Doesn't Work.

Even on some 64-bit systems a 64bit divide can be significantly
slower than a 32-bit divide - even with the same arguments.
IIRC Intel x86-64 a 64-bit divide (128-bit dividend) is about
twice the clocks of a 32-bit one. On AMD cpu they are much the same.

	David

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