For the memory hole, sparse memory model that define SPARSEMEM_VMEMMAP do not free the reserved memory for the page map, this patch do it.
Signed-off-by: Wei Li <[email protected]> Signed-off-by: Chen Feng <[email protected]> Signed-off-by: Xia Qing <[email protected]> v2: fix the patch v1 compile errors that are not based on the latest mainline. --- arch/arm64/mm/init.c | 81 +++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 71 insertions(+), 10 deletions(-) diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 1e93cfc7c47a..600889945cd0 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -441,7 +441,48 @@ void __init bootmem_init(void) memblock_dump_all(); } -#ifndef CONFIG_SPARSEMEM_VMEMMAP +#ifdef CONFIG_SPARSEMEM_VMEMMAP +#define VMEMMAP_PAGE_INUSE 0xFD +static inline void free_memmap(unsigned long start_pfn, unsigned long end_pfn) +{ + unsigned long addr, end; + unsigned long next; + pmd_t *pmd; + void *page_addr; + phys_addr_t phys_addr; + + addr = (unsigned long)pfn_to_page(start_pfn); + end = (unsigned long)pfn_to_page(end_pfn); + + pmd = pmd_off_k(addr); + for (; addr < end; addr = next, pmd++) { + next = pmd_addr_end(addr, end); + + if (!pmd_present(*pmd)) + continue; + + if (IS_ALIGNED(addr, PMD_SIZE) && + IS_ALIGNED(next, PMD_SIZE)) { + phys_addr = __pfn_to_phys(pmd_pfn(*pmd)); + memblock_free(phys_addr, PMD_SIZE); + pmd_clear(pmd); + } else { + /* If here, we are freeing vmemmap pages. */ + memset((void *)addr, VMEMMAP_PAGE_INUSE, next - addr); + page_addr = page_address(pmd_page(*pmd)); + + if (!memchr_inv(page_addr, VMEMMAP_PAGE_INUSE, + PMD_SIZE)) { + phys_addr = __pfn_to_phys(pmd_pfn(*pmd)); + memblock_free(phys_addr, PMD_SIZE); + pmd_clear(pmd); + } + } + } + + flush_tlb_all(); +} +#else static inline void free_memmap(unsigned long start_pfn, unsigned long end_pfn) { struct page *start_pg, *end_pg; @@ -468,31 +509,53 @@ static inline void free_memmap(unsigned long start_pfn, unsigned long end_pfn) memblock_free(pg, pgend - pg); } +#endif + /* * The mem_map array can get very big. Free the unused area of the memory map. */ static void __init free_unused_memmap(void) { - unsigned long start, prev_end = 0; + unsigned long start, cur_start, prev_end = 0; struct memblock_region *reg; for_each_memblock(memory, reg) { - start = __phys_to_pfn(reg->base); + cur_start = __phys_to_pfn(reg->base); #ifdef CONFIG_SPARSEMEM /* * Take care not to free memmap entries that don't exist due * to SPARSEMEM sections which aren't present. */ - start = min(start, ALIGN(prev_end, PAGES_PER_SECTION)); -#endif + start = min(cur_start, ALIGN(prev_end, PAGES_PER_SECTION)); + /* - * If we had a previous bank, and there is a space between the - * current bank and the previous, free it. + * Free memory in the case of: + * 1. if cur_start - prev_end <= PAGES_PER_SECTION, + * free pre_end ~ cur_start. + * 2. if cur_start - prev_end > PAGES_PER_SECTION, + * free pre_end ~ ALIGN(prev_end, PAGES_PER_SECTION). */ if (prev_end && prev_end < start) free_memmap(prev_end, start); + /* + * Free memory in the case of: + * if cur_start - prev_end > PAGES_PER_SECTION, + * free ALIGN_DOWN(cur_start, PAGES_PER_SECTION) ~ cur_start. + */ + if (cur_start > start && + !IS_ALIGNED(cur_start, PAGES_PER_SECTION)) + free_memmap(ALIGN_DOWN(cur_start, PAGES_PER_SECTION), + cur_start); +#else + /* + * If we had a previous bank, and there is a space between the + * current bank and the previous, free it. + */ + if (prev_end && prev_end < cur_start) + free_memmap(prev_end, cur_start); +#endif /* * Align up here since the VM subsystem insists that the * memmap entries are valid from the bank end aligned to @@ -507,7 +570,6 @@ static void __init free_unused_memmap(void) free_memmap(prev_end, ALIGN(prev_end, PAGES_PER_SECTION)); #endif } -#endif /* !CONFIG_SPARSEMEM_VMEMMAP */ /* * mem_init() marks the free areas in the mem_map and tells us how much memory @@ -524,9 +586,8 @@ void __init mem_init(void) set_max_mapnr(max_pfn - PHYS_PFN_OFFSET); -#ifndef CONFIG_SPARSEMEM_VMEMMAP free_unused_memmap(); -#endif + /* this will put all unused low memory onto the freelists */ memblock_free_all(); -- 2.15.0
