Hi, On 2026-03-26 21:42:50 -0400, Zi Yan wrote: > Replace it with a check on the max folio order of the file's address space > mapping, making sure PMD_ORDER is supported.
Question from a user space developer (who learned of this via LWN [1]): Right now MADV_COlLAPSE on file mappings appears to only only work with CONFIG_READ_ONLY_THP_FOR_FS. That's pretty sad, because I see quite consistent gains (~15%) from doing madvise(MADV_COLLAPSE) on e.g. postgres' .text - but because CONFIG_READ_ONLY_THP_FOR_FS is not enabled default (or at least not commonly, I think?) in distro kernels, it never quite seemed worth the fiddliness. Do I understand correctly that by replacing the check here (and the predecessor commits), madvise(MADV_COLLAPSE) on file mappings might actually start working in more situations on typical distro kernels? Greetings, Andres [1] https://lwn.net/SubscriberLink/1066582/b92de1d7595a01e4/
