While going through kernel source , I came across this ALIGN macro #define ALIGN <http://lxr.free-electrons.com/ident?i=ALIGN>(x <http://lxr.free-electrons.com/ident?i=x>, a <http://lxr.free-electrons.com/ident?i=a>) __ALIGN_KERNEL <http://lxr.free-electrons.com/ident?i=__ALIGN_KERNEL>((x <http://lxr.free-electrons.com/ident?i=x>), (a <http://lxr.free-electrons.com/ident?i=a>)) and #define __ALIGN_KERNEL <http://lxr.free-electrons.com/ident?i=__ALIGN_KERNEL>(x <http://lxr.free-electrons.com/ident?i=x>, a <http://lxr.free-electrons.com/ident?i=a>) __ALIGN_KERNEL_MASK <http://lxr.free-electrons.com/ident?i=__ALIGN_KERNEL_MASK>(x <http://lxr.free-electrons.com/ident?i=x>, (typeof(x <http://lxr.free-electrons.com/ident?i=x>))(a <http://lxr.free-electrons.com/ident?i=a>) - 1) #define __ALIGN_KERNEL_MASK <http://lxr.free-electrons.com/ident?i=__ALIGN_KERNEL_MASK>(x <http://lxr.free-electrons.com/ident?i=x>, mask <http://lxr.free-electrons.com/ident?i=mask>) (((x <http://lxr.free-electrons.com/ident?i=x>) + (mask <http://lxr.free-electrons.com/ident?i=mask>)) & ~(mask <http://lxr.free-electrons.com/ident?i=mask>)) What does this macro do? I have read this article http://stackoverflow.com/questions/13122846/align-macro-kernel but it was not of much help.