4.18-stable review patch. If anyone has any objections, please let me know.
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From: Mike Rapoport rppt@linux.vnet.ibm.com
[ Upstream commit d39f8fb4b7776dcb09ec3bf7a321547083078ee3 ]
The deferred memory initialization relies on section definitions, e.g PAGES_PER_SECTION, that are only available when CONFIG_SPARSEMEM=y on most architectures.
Initially DEFERRED_STRUCT_PAGE_INIT depended on explicit ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT configuration option, but since the commit 2e3ca40f03bb13709df4 ("mm: relax deferred struct page requirements") this requirement was relaxed and now it is possible to enable DEFERRED_STRUCT_PAGE_INIT on architectures that support DISCONTINGMEM and NO_BOOTMEM which causes build failures.
For instance, setting SMP=y and DEFERRED_STRUCT_PAGE_INIT=y on arc causes the following build failure:
CC mm/page_alloc.o mm/page_alloc.c: In function 'update_defer_init': mm/page_alloc.c:321:14: error: 'PAGES_PER_SECTION' undeclared (first use in this function); did you mean 'USEC_PER_SEC'? (pfn & (PAGES_PER_SECTION - 1)) == 0) { ^~~~~~~~~~~~~~~~~ USEC_PER_SEC mm/page_alloc.c:321:14: note: each undeclared identifier is reported only once for each function it appears in In file included from include/linux/cache.h:5:0, from include/linux/printk.h:9, from include/linux/kernel.h:14, from include/asm-generic/bug.h:18, from arch/arc/include/asm/bug.h:32, from include/linux/bug.h:5, from include/linux/mmdebug.h:5, from include/linux/mm.h:9, from mm/page_alloc.c:18: mm/page_alloc.c: In function 'deferred_grow_zone': mm/page_alloc.c:1624:52: error: 'PAGES_PER_SECTION' undeclared (first use in this function); did you mean 'USEC_PER_SEC'? unsigned long nr_pages_needed = ALIGN(1 << order, PAGES_PER_SECTION); ^ include/uapi/linux/kernel.h:11:47: note: in definition of macro '__ALIGN_KERNEL_MASK' #define __ALIGN_KERNEL_MASK(x, mask) (((x) + (mask)) & ~(mask)) ^~~~ include/linux/kernel.h:58:22: note: in expansion of macro '__ALIGN_KERNEL' #define ALIGN(x, a) __ALIGN_KERNEL((x), (a)) ^~~~~~~~~~~~~~ mm/page_alloc.c:1624:34: note: in expansion of macro 'ALIGN' unsigned long nr_pages_needed = ALIGN(1 << order, PAGES_PER_SECTION); ^~~~~ In file included from include/asm-generic/bug.h:18:0, from arch/arc/include/asm/bug.h:32, from include/linux/bug.h:5, from include/linux/mmdebug.h:5, from include/linux/mm.h:9, from mm/page_alloc.c:18: mm/page_alloc.c: In function 'free_area_init_node': mm/page_alloc.c:6379:50: error: 'PAGES_PER_SECTION' undeclared (first use in this function); did you mean 'USEC_PER_SEC'? pgdat->static_init_pgcnt = min_t(unsigned long, PAGES_PER_SECTION, ^ include/linux/kernel.h:812:22: note: in definition of macro '__typecheck' (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1))) ^ include/linux/kernel.h:836:24: note: in expansion of macro '__safe_cmp' __builtin_choose_expr(__safe_cmp(x, y), \ ^~~~~~~~~~ include/linux/kernel.h:904:27: note: in expansion of macro '__careful_cmp' #define min_t(type, x, y) __careful_cmp((type)(x), (type)(y), <) ^~~~~~~~~~~~~ mm/page_alloc.c:6379:29: note: in expansion of macro 'min_t' pgdat->static_init_pgcnt = min_t(unsigned long, PAGES_PER_SECTION, ^~~~~ include/linux/kernel.h:836:2: error: first argument to '__builtin_choose_expr' not a constant __builtin_choose_expr(__safe_cmp(x, y), \ ^ include/linux/kernel.h:904:27: note: in expansion of macro '__careful_cmp' #define min_t(type, x, y) __careful_cmp((type)(x), (type)(y), <) ^~~~~~~~~~~~~ mm/page_alloc.c:6379:29: note: in expansion of macro 'min_t' pgdat->static_init_pgcnt = min_t(unsigned long, PAGES_PER_SECTION, ^~~~~ scripts/Makefile.build:317: recipe for target 'mm/page_alloc.o' failed
Let's make the DEFERRED_STRUCT_PAGE_INIT explicitly depend on SPARSEMEM as the systems that support DISCONTIGMEM do not seem to have that huge amounts of memory that would make DEFERRED_STRUCT_PAGE_INIT relevant.
Link: http://lkml.kernel.org/r/1530279308-24988-1-git-send-email-rppt@linux.vnet.i... Signed-off-by: Mike Rapoport rppt@linux.vnet.ibm.com Acked-by: Michal Hocko mhocko@suse.com Reviewed-by: Pavel Tatashin pasha.tatashin@oracle.com Tested-by: Randy Dunlap rdunlap@infradead.org Cc: Pasha Tatashin Pavel.Tatashin@microsoft.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- mm/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/Kconfig +++ b/mm/Kconfig @@ -635,7 +635,7 @@ config DEFERRED_STRUCT_PAGE_INIT bool "Defer initialisation of struct pages to kthreads" default n depends on NO_BOOTMEM - depends on !FLATMEM + depends on SPARSEMEM depends on !NEED_PER_CPU_KM help Ordinarily all struct pages are initialised during early boot in a