Messages in this thread | | | Date | Thu, 17 Apr 2003 17:20:21 +0200 | From | Andi Kleen <> | Subject | Re: Reduce struct page by 8 bytes on 64bit |
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On Wed, Apr 16, 2003 at 11:40:35PM +0200, David S. Miller wrote: > From: Andrew Morton <akpm@digeo.com> > Date: Wed, 16 Apr 2003 14:43:11 -0700 > > Well are we sure that the `flags' and `count' fields will always fall into > the same 256-byte range? Wouldn't it subtly break if sizeof(struct page) > became not a multiple of eight? Will the compiler pad it out anyway? > > As long as there is a long or pointer member, the structure > will be required to be 8 byte or better aligned.
Yes that should be a safe assumption. mem_map will be always page aligned and it should be a multiple of a power of 8. That makes it impossible for it to cross a cache line.
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