From 321bf4ed5ff5f7c62ef59f33b7eec5b154391f0a Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Mon, 30 Jan 2012 13:57:12 -0800 Subject: drivers/base/memory.c: fix memory_dev_init() long delay One system with 2048g ram, reported soft lockup on recent kernel. [ 34.426749] cpu_dev_init done [ 61.166399] BUG: soft lockup - CPU#0 stuck for 22s! [swapper/0:1] [ 61.166733] Modules linked in: [ 61.166904] irq event stamp: 1935610 [ 61.178431] hardirqs last enabled at (1935609): [] mutex_lock_nested+0x299/0x2b4 [ 61.178923] hardirqs last disabled at (1935610): [] apic_timer_interrupt+0x6b/0x80 [ 61.198767] softirqs last enabled at (1935476): [] __do_softirq+0x195/0x1ab [ 61.218604] softirqs last disabled at (1935471): [] call_softirq+0x1c/0x30 [ 61.238408] CPU 0 [ 61.238549] Modules linked in: [ 61.238744] [ 61.238825] Pid: 1, comm: swapper/0 Not tainted 3.3.0-rc1-tip-yh-02076-g962f689-dirty #171 [ 61.278212] RIP: 0010:[] [] lock_release+0x90/0x9c [ 61.278627] RSP: 0018:ffff883f64dbfd70 EFLAGS: 00000246 [ 61.298287] RAX: ffff883f64dc0000 RBX: 0000000000000000 RCX: 000000000000008b [ 61.298690] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 [ 61.318383] RBP: ffff883f64dbfda0 R08: 0000000000000001 R09: 000000000000008b [ 61.338215] R10: 0000000000000000 R11: 0000000000000000 R12: ffff883f64dbfd10 [ 61.338610] R13: ffff883f64dc0708 R14: ffff883f64dc0708 R15: ffffffff81095657 [ 61.358299] FS: 0000000000000000(0000) GS:ffff883f7d600000(0000) knlGS:0000000000000000 [ 61.378118] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 61.378450] CR2: 0000000000000000 CR3: 00000000024af000 CR4: 00000000000007f0 [ 61.398144] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 61.417918] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 61.418260] Process swapper/0 (pid: 1, threadinfo ffff883f64dbe000, task ffff883f64dc0000) [ 61.445358] Stack: [ 61.445511] 0000000000000002 ffff897f649ba168 ffff883f64dbfe10 ffff88ff64bb57a8 [ 61.458040] 0000000000000000 0000000000000000 ffff883f64dbfdc0 ffffffff81ceb1b4 [ 61.458491] 000000000011608c ffff88ff64bb58a8 ffff883f64dbfdf0 ffffffff81c57638 [ 61.478215] Call Trace: [ 61.478367] [] _raw_spin_unlock+0x21/0x2e [ 61.497994] [] klist_next+0x9e/0xbc [ 61.498264] [] next_device+0xe/0x1e [ 61.517867] [] subsys_find_device_by_id+0xb7/0xd6 [ 61.518197] [] find_memory_block_hinted+0x3d/0x66 [ 61.537927] [] find_memory_block+0x10/0x12 [ 61.538193] [] add_memory_section+0x35/0x9e [ 61.557932] [] memory_dev_init+0x68/0xda [ 61.558227] [] driver_init+0x97/0xa7 [ 61.577853] [] kernel_init+0xf6/0x1c0 [ 61.578140] [] kernel_thread_helper+0x4/0x10 [ 61.597850] [] ? retint_restore_args+0xe/0xe [ 61.598144] [] ? start_kernel+0x3ab/0x3ab [ 61.617826] [] ? gs_change+0xb/0xb [ 61.618060] Code: 10 48 83 3b 00 eb e8 4c 89 f2 44 89 fe 4c 89 ef e8 e1 fe ff ff 65 48 8b 04 25 40 bc 00 00 c7 80 cc 06 00 00 00 00 00 00 41 54 9d <5e> 5b 41 5c 41 5d 41 5e 41 5f 5d c3 55 48 89 e5 41 57 41 89 cf [ 89.285380] memory_dev_init done Finally it takes about 55s to create 16400 memory entries. Root cause: for x86_64, 2048g (with 2g hole at [2g,4g), and TOP2 will be 2050g), will have 16400 memory block. find_memory_block/subsys_find_device_by_id will be expensive with that many entries. Actually, we don't need to find that memory block for BOOT path. Skip that finding make it get back to normal. [ 34.466696] cpu_dev_init done [ 35.290080] memory_dev_init done Also solved the delay with topology_init when sections_per_block is not 1. Signed-off-by: Yinghai Lu Cc: Kay Sievers Cc: Nathan Fontenot Cc: Robin Holt Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- drivers/base/memory.c | 31 ++++++++++++++++++++++++++----- drivers/base/node.c | 8 ++++++++ 2 files changed, 34 insertions(+), 5 deletions(-) diff --git a/drivers/base/memory.c b/drivers/base/memory.c index ed5de58c340..9e60dbe9fd9 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -572,19 +572,36 @@ static int init_memory_block(struct memory_block **memory, } static int add_memory_section(int nid, struct mem_section *section, + struct memory_block **mem_p, unsigned long state, enum mem_add_context context) { - struct memory_block *mem; + struct memory_block *mem = NULL; + int scn_nr = __section_nr(section); int ret = 0; mutex_lock(&mem_sysfs_mutex); - mem = find_memory_block(section); + if (context == BOOT) { + /* same memory block ? */ + if (mem_p && *mem_p) + if (scn_nr >= (*mem_p)->start_section_nr && + scn_nr <= (*mem_p)->end_section_nr) { + mem = *mem_p; + kobject_get(&mem->dev.kobj); + } + } else + mem = find_memory_block(section); + if (mem) { mem->section_count++; kobject_put(&mem->dev.kobj); - } else + } else { ret = init_memory_block(&mem, section, state); + /* store memory_block pointer for next loop */ + if (!ret && context == BOOT) + if (mem_p) + *mem_p = mem; + } if (!ret) { if (context == HOTPLUG && @@ -627,7 +644,7 @@ int remove_memory_block(unsigned long node_id, struct mem_section *section, */ int register_new_memory(int nid, struct mem_section *section) { - return add_memory_section(nid, section, MEM_OFFLINE, HOTPLUG); + return add_memory_section(nid, section, NULL, MEM_OFFLINE, HOTPLUG); } int unregister_memory_section(struct mem_section *section) @@ -647,6 +664,7 @@ int __init memory_dev_init(void) int ret; int err; unsigned long block_sz; + struct memory_block *mem = NULL; ret = subsys_system_register(&memory_subsys, NULL); if (ret) @@ -662,7 +680,10 @@ int __init memory_dev_init(void) for (i = 0; i < NR_MEM_SECTIONS; i++) { if (!present_section_nr(i)) continue; - err = add_memory_section(0, __nr_to_section(i), MEM_ONLINE, + /* don't need to reuse memory_block if only one per block */ + err = add_memory_section(0, __nr_to_section(i), + (sections_per_block == 1) ? NULL : &mem, + MEM_ONLINE, BOOT); if (!ret) ret = err; diff --git a/drivers/base/node.c b/drivers/base/node.c index 44f427a6611..90aa2a11a93 100644 --- a/drivers/base/node.c +++ b/drivers/base/node.c @@ -456,7 +456,15 @@ static int link_mem_sections(int nid) if (!present_section_nr(section_nr)) continue; mem_sect = __nr_to_section(section_nr); + + /* same memblock ? */ + if (mem_blk) + if ((section_nr >= mem_blk->start_section_nr) && + (section_nr <= mem_blk->end_section_nr)) + continue; + mem_blk = find_memory_block_hinted(mem_sect, mem_blk); + ret = register_mem_sect_under_node(mem_blk, nid); if (!err) err = ret; -- cgit v1.2.3-70-g09d2