On Sat, 30 May 2015 01:48:20 +0800 kbuild test robot <fengguang.wu@xxxxxxxxx> wrote: > tree: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master > head: 7732a9817fb01002bde7615066e86c156fb5a31b > commit: 0491d0d6aac97c5b8df17851db525f3758de26e6 [7235/7555] s390/mm: make hugepages_supported a boot time decision > config: s390-defconfig (attached as .config) > reproduce: > wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross > chmod +x ~/bin/make.cross > git checkout 0491d0d6aac97c5b8df17851db525f3758de26e6 > # save the attached .config to linux build tree > make.cross ARCH=s390 > > All warnings: > > mm/page_alloc.c: In function '__free_one_page': > >> mm/page_alloc.c:654:121: warning: comparison of distinct pointer types lacks a cast > max_order = min(MAX_ORDER, pageblock_order + 1); > ^ > -- > mm/cma.c: In function 'cma_init_reserved_mem': > >> mm/cma.c:186:137: warning: comparison of distinct pointer types lacks a cast > alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order); Dominik's patch has somehow managed to change the type of pageblock_order. Before the patch, pageblock_order expands to "(20 - 12)". After the patch, pageblock_order expands to "(HPAGE_SHIFT - 12)". And on s390, HPAGE_SHIFT is unsigned int. On x86 HPAGE_SHIFT has type int. I suggest the fix here is to make s390's HPAGE_SHIFT have type int as well. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>