From: Joe Perches > Sent: 07 October 2021 17:28 ... > IMO: this new file is missing 2 #include directives. ... > This is not a self-contained header as it requires > #include <linux/build_bug.h> > which should be at the top of this file. ... > And this requires > > #include <linux/err.h> And I bet the biggest problem is the time spent by the compiler searching down the -I path for headers. If you count system calls during a build I suspect that failed opens of .h files dominate. To see how much this really costs try running a build with a (traditional) NFS mounted source tree - where every directory name in a filename requires an NFS file handle lookup. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
