• Mark Rutland's avatar
    locking/atomics: build atomic headers as required · 24915609
    Mark Rutland authored
    Andrew and Ingo report that the check-atomics.sh script is simply too slow
    to run for every kernel build, and it's impractical to make it faster
    without rewriting it in something other than shell.
    
    Rather than committing the generated headers, let's regenerate these
    as-required for a pristine tree.
    
    That ensures they're always up-to-date, allows them to be built in
    parallel, and avoid redundant rebuilds, which is a 2-8s saving per
    incremental build.  Since the results are not committed, it's very obvious
    that they should not be modified directly.  If we need to generate more
    headers in future, it's easy to extend Makefile.genheader to permit this.
    
    I've verified that this works in the cases we previously had issues with
    (out-of-tree builds and where scripts have no execute permissions), and
    have tested these cases for both x86_64 and arm64.
    
    The diffstat looks nice, at least...
    
    Link: http://lkml.kernel.org/r/20181123153321.8561-1-mark.rutland@arm.comSigned-off-by: 's avatarMark Rutland <mark.rutland@arm.com>
    Cc: Boqun Feng <boqun.feng@gmail.com>
    Cc: Borislav Petkov <bp@suse.de>
    Cc: Ingo Molnar <mingo@kernel.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Will Deacon <will.deacon@arm.com>
    Signed-off-by: 's avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: 's avatarStephen Rothwell <sfr@canb.auug.org.au>
    24915609
Makefile 59.2 KB