From c5a8f13e0ec8ba787dc9549164df28291530ca6f Mon Sep 17 00:00:00 2001 From: Mike Rapoport Date: Fri, 14 Jan 2022 19:34:40 +0800 Subject: [PATCH] memblock: free_unused_memmap: use pageblock units instead of MAX_ORDER stable inclusion from stable-v5.10.87 commit b4b54c7ba149ffa2dcb11b2a84ebf20189ff7f89 bugzilla: 186049 https://gitee.com/openeuler/kernel/issues/I4QVYL Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b4b54c7ba149ffa2dcb11b2a84ebf20189ff7f89 -------------------------------- [ Upstream commit e2a86800d58639b3acde7eaeb9eb393dca066e08 ] The code that frees unused memory map uses rounds start and end of the holes that are freed to MAX_ORDER_NR_PAGES to preserve continuity of the memory map for MAX_ORDER regions. Lots of core memory management functionality relies on homogeneity of the memory map within each pageblock which size may differ from MAX_ORDER in certain configurations. Although currently, for the architectures that use free_unused_memmap(), pageblock_order and MAX_ORDER are equivalent, it is cleaner to have common notation thought mm code. Replace MAX_ORDER_NR_PAGES with pageblock_nr_pages and update the comments to make it more clear why the alignment to pageblock boundaries is required. Signed-off-by: Mike Rapoport Tested-by: Tony Lindgren Link: https://lore.kernel.org/lkml/20210630071211.21011-1-rppt@kernel.org/ [backport upstream modification in mm/memblock.c to arch/arm/mm/init.c] Signed-off-by: Mark-PK Tsai Signed-off-by: Greg Kroah-Hartman Signed-off-by: Chen Jun Signed-off-by: Zheng Zengkai --- arch/arm/mm/init.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c index 75f3ab531bdf..8440b6027598 100644 --- a/arch/arm/mm/init.c +++ b/arch/arm/mm/init.c @@ -315,11 +315,11 @@ static void __init free_unused_memmap(void) ALIGN(prev_end, PAGES_PER_SECTION)); #else /* - * Align down here since the VM subsystem insists that the - * memmap entries are valid from the bank start aligned to - * MAX_ORDER_NR_PAGES. + * Align down here since many operations in VM subsystem + * presume that there are no holes in the memory map inside + * a pageblock */ - start = round_down(start, MAX_ORDER_NR_PAGES); + start = round_down(start, pageblock_nr_pages); #endif /* * If we had a previous bank, and there is a space @@ -329,11 +329,11 @@ static void __init free_unused_memmap(void) free_memmap(prev_end, start); /* - * Align up here since the VM subsystem insists that the - * memmap entries are valid from the bank end aligned to - * MAX_ORDER_NR_PAGES. + * Align up here since many operations in VM subsystem + * presume that there are no holes in the memory map inside + * a pageblock */ - prev_end = ALIGN(end, MAX_ORDER_NR_PAGES); + prev_end = ALIGN(end, pageblock_nr_pages); } #ifdef CONFIG_SPARSEMEM -- GitLab