| From foo@baz Wed Dec 15 03:02:39 PM CET 2021 |
| From: Mark-PK Tsai <mark-pk.tsai@mediatek.com> |
| Date: Mon, 13 Dec 2021 16:57:06 +0800 |
| Subject: memblock: free_unused_memmap: use pageblock units instead of MAX_ORDER |
| To: <stable@vger.kernel.org> |
| Cc: <rppt@kernel.org>, <akpm@linux-foundation.org>, <linux-arm-kernel@lists.infradead.org>, <linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>, <linux@armlinux.org.uk>, <rppt@linux.ibm.com>, <tony@atomide.com>, <wangkefeng.wang@huawei.com>, <mark-pk.tsai@mediatek.com>, <yj.chiang@mediatek.com> |
| Message-ID: <20211213085710.28962-2-mark-pk.tsai@mediatek.com> |
| |
| From: Mike Rapoport <rppt@linux.ibm.com> |
| |
| commit e2a86800d58639b3acde7eaeb9eb393dca066e08 upstream. |
| |
| 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 <rppt@linux.ibm.com> |
| Tested-by: Tony Lindgren <tony@atomide.com> |
| 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 <mark-pk.tsai@mediatek.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| arch/arm/mm/init.c | 16 ++++++++-------- |
| 1 file changed, 8 insertions(+), 8 deletions(-) |
| |
| --- a/arch/arm/mm/init.c |
| +++ b/arch/arm/mm/init.c |
| @@ -373,11 +373,11 @@ static void __init free_unused_memmap(vo |
| 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 |
| @@ -387,12 +387,12 @@ static void __init free_unused_memmap(vo |
| 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(memblock_region_memory_end_pfn(reg), |
| - MAX_ORDER_NR_PAGES); |
| + pageblock_nr_pages); |
| } |
| |
| #ifdef CONFIG_SPARSEMEM |