Messages in this thread | | | Date | Mon, 4 Jul 2022 08:07:00 +0200 | From | Christoph Hellwig <> | Subject | Re: [PATCH v7 16/21] block: add check when merging zone device pages |
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On Thu, Jun 30, 2022 at 03:50:10PM -0600, Logan Gunthorpe wrote: > Oh, it turns out this code has nothing to do with REQ_NOMERGE. It's used > indirectly in bio_map_user_iov() and __bio_iov_iter_get_pages() when > adding pages to the bio via page_is_mergeable(). So it's not about > requests being merged it's about pages being merged.
Oh, true.
> So I'm not sure how we can avoid this, but it only happens when two > adjacent pages are added to the same bio in a row, so I don't think it's > that common, but the check can probably be moved down so it happens > after the same_page check to make it a little less common.
Yes, looks like we have to keep it.
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