On Fri, 6 May 2022 00:43:18 +0100 Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: > - Fix readahead creating single-page folios instead of the intended > large folios when doing reads that are not a power of two in size. I worry about the idea of using hugepages in readahead. We're increasing the load on the hugepage allocator, which is already groaning under the load. The obvious risk is that handing out hugepages to a low-value consumer (copying around pagecache which is only ever accessed via the direct map) will deny their availability to high-value consumers (that compute-intensive task against a large dataset). Has testing and instrumentation been used to demonstrate that this is not actually going to be a problem, or are we at risk of getting unhappy reports?
