I'm one of the Google engineers who work on multigenerational LRU. The kernel page cache doesn't know better than databases themselves when it comes to what to

I'm one of the Google engineers who work on multigenerational LRU. The kernel page cache doesn't know better than databases themselves when it comes to what to cache. All high performance databases do this in user space, and they use AIO with direct IO or the latest io_uring to bypass the kernel page cache. Modern cloud (distributed) file systems do the same, including GFS: https://en.wikipedia.org/wiki/Google_File_System https://en.wikipedia.org/wiki/Google_File_System And speaking of io_uring, check this out to see how much improvement when copying without going through page cache: https://wheybags.com/blog/wcp.html https://wheybags.com/blog/wcp.html