Re: [RFC 1/3] lib: copy_{from,to}_user using gup & kmap_atomic()
From: Al Viro <viro@zeniv.linux.org.uk>
Date: 2020-06-13 15:32:59
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On Sat, Jun 13, 2020 at 07:12:36PM +0530, afzal mohammed wrote:
Hi, On Sat, Jun 13, 2020 at 01:56:15PM +0100, Al Viro wrote:quoted
Incidentally, what about get_user()/put_user()? _That_ is where it's going to really hurt...All other uaccess routines are also planned to be added, posting only copy_{from,to}_user() was to get early feedback (mentioned in the cover letter)
Sure, but what I mean is that I'd expect the performance loss to be dominated by that, not by copy_from_user/copy_to_user on large amounts of data. Especially on the loads like kernel builds - a lot of stat() and getdents() calls there. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel