On Tue, Apr 20, 2010 at 03:51:22PM -0700, Andrew Morton wrote: > On Mon, 19 Apr 2010 20:27:43 -0300 > Marcelo Jimenez <mroberto@xxxxxxxxxxxxxxxxxxxxx> wrote: > > > I get this warning while compiling for ARM/SA1100: > > > > mm/sparse.c: In function '__section_nr': > > mm/sparse.c:135: warning: 'root' is used uninitialized in this function > > > > With a small patch in fs/proc/meminfo.c, I find that NR_SECTION_ROOTS > > is zero, which certainly explains the warning. > > > > # cat /proc/meminfo > > NR_SECTION_ROOTS=0 > > NR_MEM_SECTIONS=32 > > SECTIONS_PER_ROOT=512 > > SECTIONS_SHIFT=5 > > MAX_PHYSMEM_BITS=32 > > hm, who owns sparsemem nowadays? Nobody identifiable. > > Does it make physical sense to have SECTIONS_PER_ROOT > NR_MEM_SECTIONS? Well, it'll be about this number on everything using sparsemem extreme: #define SECTIONS_PER_ROOT (PAGE_SIZE / sizeof (struct mem_section)) and with only 32 sections, this is going to give a NR_SECTION_ROOTS value of zero. I think the calculation of NR_SECTIONS_ROOTS is wrong. #define NR_SECTION_ROOTS (NR_MEM_SECTIONS / SECTIONS_PER_ROOT) Clearly if we have 1 mem section, we want to have one section root, so I think this division should round up any fractional part, thusly: #define NR_SECTION_ROOTS ((NR_MEM_SECTIONS + SECTIONS_PER_ROOT - 1) / SECTIONS_PER_ROOT) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>