github.com/grailbio/base@v0.0.11/file/internal/kernel/kernel.go (about)

     1  package kernel
     2  
     3  // MaxReadAhead configures the kernel's maximum readahead for file handles on this FUSE mount
     4  // (via ConfigureMount) and our corresponding "trailing" buffer.
     5  //
     6  // Our sizingHandle implements Read operations for read-only fsctx.File objects that don't support
     7  // random access or seeking. Generally this requires that the user reading such a file does so
     8  // in-order. However, the kernel attempts to optimize i/o speed by reading ahead into the page cache
     9  // and to do so it can issue concurrent reads for a few blocks ahead of the user's current position.
    10  // We respond to such requests from our trailing buffer.
    11  // TODO: Choose a value more carefully. This value was chosen fairly roughly based on some
    12  // articles/discussion that suggested this was a kernel default.
    13  const MaxReadAhead = 512 * 1024