• Dave Hansen's avatar
    x86/fpu, sched: Dynamically allocate 'struct fpu' · 0c8c0f03
    Dave Hansen authored
    The FPU rewrite removed the dynamic allocations of 'struct fpu'.
    But, this potentially wastes massive amounts of memory (2k per
    task on systems that do not have AVX-512 for instance).
    
    Instead of having a separate slab, this patch just appends the
    space that we need to the 'task_struct' which we dynamically
    allocate already.  This saves from doing an extra slab
    allocation at fork().
    
    The only real downside here is that we have to stick everything
    and the end of the task_struct.  But, I think the
    BUILD_BUG_ON()s I stuck in there should keep that from being too
    fragile.
    Signed-off-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
    Cc: Andy Lutomirski <luto@amacapital.net>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Brian Gerst <brgerst@gmail.com>
    Cc: Dave Hansen <dave@sr71.net>
    Cc: Denys Vlasenko <dvlasenk@redhat.com>
    Cc: H. Peter Anvin <hpa@zytor.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Oleg Nesterov <oleg@redhat.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Link: http://lkml.kernel.org/r/1437128892-9831-2-git-send-email-mingo@kernel.orgSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
    0c8c0f03
processor.h 21.1 KB