From 7c21d533ab2ffa1e681bdaf4a53ce3046f6e0e17 Mon Sep 17 00:00:00 2001 From: bob picco Date: Tue, 16 Sep 2014 09:29:54 -0400 Subject: [PATCH] sparc64: mem boot option correction The "mem" boot option can result in many unexpected consequences. This patch attempts to prevent boot hangs which have been experienced on T4-4 and T5-8. Basically the boot loader allocates vmlinuz and initrd higher in available OBP physical memory. For example, on a 2Tb T5-8 it isn't possible to boot with mem=20G. The patch utilizes memblock to avoid reserved regions and trim memory which is only free. Other improvements are possible for a multi-node machine. This is a snippet of the boot log with mem=20G on T5-8 with the patch applied: MEMBLOCK configuration: <- before memory reduction memory size = 0x1ffad6ce000 reserved size = 0xa1adf44 memory.cnt = 0xb memory[0x0] [0x00000030400000-0x00003fdde47fff], 0x3fada48000 bytes memory[0x1] [0x00003fdde4e000-0x00003fdde4ffff], 0x2000 bytes memory[0x2] [0x00080000000000-0x00083fffffffff], 0x4000000000 bytes memory[0x3] [0x00100000000000-0x00103fffffffff], 0x4000000000 bytes memory[0x4] [0x00180000000000-0x00183fffffffff], 0x4000000000 bytes memory[0x5] [0x00200000000000-0x00203fffffffff], 0x4000000000 bytes memory[0x6] [0x00280000000000-0x00283fffffffff], 0x4000000000 bytes memory[0x7] [0x00300000000000-0x00303fffffffff], 0x4000000000 bytes memory[0x8] [0x00380000000000-0x00383fffc71fff], 0x3fffc72000 bytes memory[0x9] [0x00383fffc92000-0x00383fffca1fff], 0x10000 bytes memory[0xa] [0x00383fffcb4000-0x00383fffcb5fff], 0x2000 bytes reserved.cnt = 0x2 reserved[0x0] [0x00380000000000-0x0038000117e7f8], 0x117e7f9 bytes reserved[0x1] [0x00380004000000-0x0038000d02f74a], 0x902f74b bytes ... MEMBLOCK configuration: <- after reduction of memory memory size = 0x50a1adf44 reserved size = 0xa1adf44 memory.cnt = 0x4 memory[0x0] [0x00380000000000-0x0038000117e7f8], 0x117e7f9 bytes memory[0x1] [0x00380004000000-0x0038050d01d74a], 0x50901d74b bytes memory[0x2] [0x00383fffc92000-0x00383fffca1fff], 0x10000 bytes memory[0x3] [0x00383fffcb4000-0x00383fffcb5fff], 0x2000 bytes reserved.cnt = 0x2 reserved[0x0] [0x00380000000000-0x0038000117e7f8], 0x117e7f9 bytes reserved[0x1] [0x00380004000000-0x0038000d02f74a], 0x902f74b bytes ... Early memory node ranges node 7: [mem 0x380000000000-0x38000117dfff] node 7: [mem 0x380004000000-0x380f0d01bfff] node 7: [mem 0x383fffc92000-0x383fffca1fff] node 7: [mem 0x383fffcb4000-0x383fffcb5fff] Could not find start_pfn for node 0 Could not find start_pfn for node 1 Could not find start_pfn for node 2 Could not find start_pfn for node 3 Could not find start_pfn for node 4 Could not find start_pfn for node 5 Could not find start_pfn for node 6 . The patch was tested on T4-1, T5-8 and Jalap?no. Cc: sparclinux@vger.kernel.org Signed-off-by: Bob Picco Signed-off-by: David S. Miller --- arch/sparc/kernel/setup_64.c | 18 +++---------- arch/sparc/mm/init_64.c | 49 +++++++++++++++++++++++++++++++++++- 2 files changed, 51 insertions(+), 16 deletions(-) diff --git a/arch/sparc/kernel/setup_64.c b/arch/sparc/kernel/setup_64.c index 1c7bfdf83b66..e629b8377587 100644 --- a/arch/sparc/kernel/setup_64.c +++ b/arch/sparc/kernel/setup_64.c @@ -141,21 +141,9 @@ static void __init boot_flags_init(char *commands) process_switch(*commands++); continue; } - if (!strncmp(commands, "mem=", 4)) { - /* - * "mem=XXX[kKmM]" overrides the PROM-reported - * memory size. - */ - cmdline_memory_size = simple_strtoul(commands + 4, - &commands, 0); - if (*commands == 'K' || *commands == 'k') { - cmdline_memory_size <<= 10; - commands++; - } else if (*commands=='M' || *commands=='m') { - cmdline_memory_size <<= 20; - commands++; - } - } + if (!strncmp(commands, "mem=", 4)) + cmdline_memory_size = memparse(commands + 4, &commands); + while (*commands && *commands != ' ') commands++; } diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c index 3b045058d726..c8bccafea4f3 100644 --- a/arch/sparc/mm/init_64.c +++ b/arch/sparc/mm/init_64.c @@ -1861,6 +1861,52 @@ pgd_t swapper_pg_dir[PTRS_PER_PGD]; static void sun4u_pgprot_init(void); static void sun4v_pgprot_init(void); +static phys_addr_t __init available_memory(void) +{ + phys_addr_t available = 0ULL; + phys_addr_t pa_start, pa_end; + u64 i; + + for_each_free_mem_range(i, NUMA_NO_NODE, &pa_start, &pa_end, NULL) + available = available + (pa_end - pa_start); + + return available; +} + +/* We need to exclude reserved regions. This exclusion will include + * vmlinux and initrd. To be more precise the initrd size could be used to + * compute a new lower limit because it is freed later during initialization. + */ +static void __init reduce_memory(phys_addr_t limit_ram) +{ + phys_addr_t avail_ram = available_memory(); + phys_addr_t pa_start, pa_end; + u64 i; + + if (limit_ram >= avail_ram) + return; + + for_each_free_mem_range(i, NUMA_NO_NODE, &pa_start, &pa_end, NULL) { + phys_addr_t region_size = pa_end - pa_start; + phys_addr_t clip_start = pa_start; + + avail_ram = avail_ram - region_size; + /* Are we consuming too much? */ + if (avail_ram < limit_ram) { + phys_addr_t give_back = limit_ram - avail_ram; + + region_size = region_size - give_back; + clip_start = clip_start + give_back; + } + + memblock_remove(clip_start, region_size); + + if (avail_ram <= limit_ram) + break; + i = 0UL; + } +} + void __init paging_init(void) { unsigned long end_pfn, shift, phys_base; @@ -1940,7 +1986,8 @@ void __init paging_init(void) find_ramdisk(phys_base); - memblock_enforce_memory_limit(cmdline_memory_size); + if (cmdline_memory_size) + reduce_memory(cmdline_memory_size); memblock_allow_resize(); memblock_dump_all(); -- 2.34.1