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    mm,slub,x86: decouple size of struct page from CONFIG_CMPXCHG_LOCAL · 43570fd2
    Heiko Carstens 提交于
    While implementing cmpxchg_double() on s390 I realized that we don't set
    CONFIG_CMPXCHG_LOCAL despite the fact that we have support for it.
    
    However setting that option will increase the size of struct page by
    eight bytes on 64 bit, which we certainly do not want.  Also, it doesn't
    make sense that a present cpu feature should increase the size of struct
    page.
    
    Besides that it looks like the dependency to CMPXCHG_LOCAL is wrong and
    that it should depend on CMPXCHG_DOUBLE instead.
    
    This patch:
    
    If an architecture supports CMPXCHG_LOCAL this shouldn't result
    automatically in larger struct pages if the SLUB allocator is used.
    Instead introduce a new config option "HAVE_ALIGNED_STRUCT_PAGE" which
    can be selected if a double word aligned struct page is required.  Also
    update x86 Kconfig so that it should work as before.
    Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
    Acked-by: NChristoph Lameter <cl@linux.com>
    Cc: Pekka Enberg <penberg@kernel.org>
    Cc: Ingo Molnar <mingo@elte.hu>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: "H. Peter Anvin" <hpa@zytor.com>
    Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
    43570fd2
Kconfig 69.9 KB