From: Yu Zhao <yuzhao@xxxxxxxxxx> Subject: include/linux/page-flags-layout.h: correctly determine LAST_CPUPID_WIDTH The naming convention used in include/linux/page-flags-layout.h: *_SHIFT: the number of bits trying to allocate *_WIDTH: the number of bits successfully allocated So when it comes to LAST_CPUPID_WIDTH, we need to check whether all previous *_WIDTH and LAST_CPUPID_SHIFT can fit into page flags. This means we need to use NODES_WIDTH, not NODES_SHIFT. Link: https://lkml.kernel.org/r/20210303071609.797782-1-yuzhao@xxxxxxxxxx Signed-off-by: Yu Zhao <yuzhao@xxxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/page-flags-layout.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/include/linux/page-flags-layout.h~mm-correctly-determine-last_cpupid_width +++ a/include/linux/page-flags-layout.h @@ -83,7 +83,7 @@ #define KASAN_TAG_WIDTH 0 #endif -#if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT+LAST_CPUPID_SHIFT+KASAN_TAG_WIDTH \ +#if SECTIONS_WIDTH+ZONES_WIDTH+NODES_WIDTH+LAST_CPUPID_SHIFT+KASAN_TAG_WIDTH \ <= BITS_PER_LONG - NR_PAGEFLAGS #define LAST_CPUPID_WIDTH LAST_CPUPID_SHIFT #else _
