On Mon, Sep 01, 2008 at 12:59:28PM +0530, Balbir Singh wrote:
> While trying to build the memory resource controller with the latest
> kernel source, I saw the following in config-generic
> #NOTE: Before changing the size below, take notice that page struct
> will grow past a cacheline on 32 bit.
> I am running F10-alpha 32 bit version, on which I see
> Linux localhost.localdomain 2.6.27-0.166.rc0.git8.fc10.i686 #1 SMP Mon
> Jul 21 20:51:26 EDT 2008 i686 i686 i386 GNU/Linux
> sizeof(vma)=84 bytes
> sizeof(page)=56 bytes
> sizeof(inode)=608 bytes
> sizeof(dentry)=160 bytes
> sizeof(ext3inode)=860 bytes
> sizeof(buffer_head)=56 bytes
> sizeof(skbuff)=184 bytes
> sizeof(task_struct)=6056 bytes
> With size at 56 bytes, I don't think adding 4 bytes will affect the
> growth beyond cacheline size.
Yes, but that's with debug options on. With debug options off,
on 32bit we're currently at exactly a 32 byte cacheline, so adding
a member for CGROUP will push us past 1 cacheline.
> I suspect that there are a few debugging options turned on, that are
> causing either spinlock_t to bloat or something that CONFIG_PAGE_OWNER
> is turned on. Are these debugging options going to go away as we head
> towards F10 release?
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