Messages in this thread |  | | Date | Sat, 9 Apr 2022 07:06:38 +0200 | From | Christoph Hellwig <> | Subject | Re: [PATCH] tmpfs: fix regressions from wider use of ZERO_PAGE |
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On Fri, Apr 08, 2022 at 01:38:41PM -0700, Hugh Dickins wrote: > + } else if (iter_is_iovec(to)) { > + /* > + * Copy to user tends to be so well optimized, but > + * clear_user() not so much, that it is noticeably > + * faster to copy the zero page instead of clearing. > + */ > + ret = copy_page_to_iter(ZERO_PAGE(0), offset, nr, to);
Is the offset and length guaranteed to be less than PAGE_SIZE here?
Either way I'd rather do this optimization in iov_iter_zero rather than hiding it in tmpfs.
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