Messages in this thread | | | Date | Wed, 23 Jan 2008 19:29:15 +0200 (EET) | From | Pekka J Enberg <> | Subject | Re: [PATCH] Fix boot problem in situations where the boot CPU is running on a memoryless node |
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Hi,
On Wed, 23 Jan 2008, Mel Gorman wrote: > Applied in combination with the N_NORMAL_MEMORY revert and it fails to > boot. Console is as follows;
Thanks for testing!
On Wed, 23 Jan 2008, Mel Gorman wrote: > [c0000000005c3b40] c0000000000dadb4 .cache_grow+0x7c/0x338 > [c0000000005c3c00] c0000000000db518 .fallback_alloc+0x1c0/0x224 > [c0000000005c3cb0] c0000000000db920 .kmem_cache_alloc+0xe0/0x14c > [c0000000005c3d50] c0000000000dcbd0 .kmem_cache_create+0x230/0x4cc > [c0000000005c3e30] c0000000004c049c .kmem_cache_init+0x1ec/0x51c > [c0000000005c3ee0] c00000000049f8d8 .start_kernel+0x304/0x3fc > [c0000000005c3f90] c000000000008594 .start_here_common+0x54/0xc0 > > 0xc0000000000dadb4 is in cache_grow (mm/slab.c:2782). > 2777 local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK); > 2778 > 2779 /* Take the l3 list lock to change the colour_next on this node */ > 2780 check_irq_off(); > 2781 l3 = cachep->nodelists[nodeid]; > 2782 spin_lock(&l3->list_lock); > 2783 > 2784 /* Get colour for the slab, and cal the next value. */ > 2785 offset = l3->colour_next; > 2786 l3->colour_next++;
Ok, so it's too early to fallback_alloc() because in kmem_cache_init() we do:
for (i = 0; i < NUM_INIT_LISTS; i++) { kmem_list3_init(&initkmem_list3[i]); if (i < MAX_NUMNODES) cache_cache.nodelists[i] = NULL; }
Fine. But, why are we hitting fallback_alloc() in the first place? It's definitely not because of missing ->nodelists as we do:
cache_cache.nodelists[node] = &initkmem_list3[CACHE_CACHE];
before attempting to set up kmalloc caches. Now, if I understood correctly, we're booting off a memoryless node so kmem_getpages() will return NULL thus forcing us to fallback_alloc() which is unavailable at this point.
As far as I can tell, there are two ways to fix this:
(1) don't boot off a memoryless node (why are we doing this in the first place?) (2) initialize cache_cache.nodelists with initmem_list3 equivalents for *each node hat has normal memory*
I am still wondering why this worked before, though.
Pekka
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