While examining percpu section on i386 I found we were wasting about 8000 bytes because of two large holes : c05dd000 D __per_cpu_start c05dd000 D per_cpu__current_task c05dd004 D per_cpu__cpu_number c05dd008 D per_cpu__irq_regs c05dd00c D per_cpu__x86_cpu_to_apicid c05dd010 d per_cpu__cpu_devices c05dd044 D per_cpu__cyc2ns *HOLE* of 4Kbytes c05de000 d per_cpu__cpuid4_info c05de004 d per_cpu__cache_kobject c05de008 d per_cpu__index_kobject *HOLE* of 4Kbytes c05df000 D per_cpu__gdt_page c05e0000 d per_cpu__next_check c05e0008 d per_cpu__thermal_throttle_count This is because gdt_page is a percpu variable, defined with a page alignement, and linker is doing its job, two times because of .o nesting in the build process, mixing variables with quite different alignment requirements. I introduced a new macro DEFINE_PER_CPU_PAGE_ALIGNED() to avoid wasting this space. All page aligned variables (only one at this time) are put in a separate subsection .data.percpu.page_aligned. # size -A vmlinux.old vmlinux | grep percpu .data.percpu 22272 3227373568 .data.percpu 30336 3227373568 Thats 8064 bytes saved for each CPU (plus one for the .data.percpu storage itself) Signed-off-by: Eric Dumazet