CONFIG_CGROUP_MEM_RES_CTLR

[Dave Jones]

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?

Yes.

	Dave

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