21 Aug
2019
21 Aug
'19
1:48 a.m.
On Tue, Aug 20, 2019 at 01:06:25PM +0200, Vlastimil Babka wrote:
The whole point of copy_page is to copy exactly one page and it makes sense to assume that is aligned. A sane memcpy would use the same underlying primitives as well after checking they fit. So I think the prime issue here is btrfs' use of copy_page instead of memcpy. The secondary issue is slub fucking up alignments for no good reason. We just got bitten by that crap again in XFS as well :(
Meh, I should finally get back to https://lwn.net/Articles/787740/ right
Yes. For now Dave came up with an idea for a workaround that will be forward-compatible with that: