Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> writes:
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 8afa63e81e73..15bba5c325a5 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -7169,6 +7169,17 @@ static unsigned long __init arch_reserved_kernel_pages(void)
> #endif
>
> /*
> + * Adaptive scale is meant to reduce sizes of hash tables on large memory
> + * machines. As memory size is increased the scale is also increased but at
> + * slower pace. Starting from ADAPT_SCALE_BASE (64G), every time memory
> + * quadruples the scale is increased by one, which means the size of hash table
> + * only doubles, instead of quadrupling as well.
> + */
> +#define ADAPT_SCALE_BASE (64ull << 30)
> +#define ADAPT_SCALE_SHIFT 2
> +#define ADAPT_SCALE_NPAGES (ADAPT_SCALE_BASE >> PAGE_SHIFT)
> +
> +/*
> * allocate a large system hash table from bootmem
> * - it is assumed that the hash table must contain an exact power-of-2
> * quantity of entries
> @@ -7199,6 +7210,14 @@ void *__init alloc_large_system_hash(const char *tablename,
> if (PAGE_SHIFT < 20)
> numentries = round_up(numentries, (1<<20)/PAGE_SIZE);
>
> + if (!high_limit) {
> + unsigned long long adapt;
> +
> + for (adapt = ADAPT_SCALE_NPAGES; adapt < numentries;
> + adapt <<= ADAPT_SCALE_SHIFT)
> + scale++;
> + }
This still doesn't work for me. The scale++ is overflowing according to
UBSAN (line 7221).
It looks like numentries is 194560.
00000950 68 0a 50 49 44 20 68 61 73 68 20 74 61 62 6c 65 |h.PID hash table|
00000960 20 65 6e 74 72 69 65 73 3a 20 34 30 39 36 20 28 | entries: 4096 (|
00000970 6f 72 64 65 72 3a 20 32 2c 20 31 36 33 38 34 20 |order: 2, 16384 |
00000980 62 79 74 65 73 29 0a 61 6c 6c 6f 63 5f 6c 61 72 |bytes).alloc_lar|
00000990 67 65 5f 73 79 73 74 65 6d 5f 68 61 73 68 3a 20 |ge_system_hash: |
000009a0 6e 75 6d 65 6e 74 72 69 65 73 20 31 39 34 35 36 |numentries 19456|
000009b0 30 0a 61 6c 6c 6f 63 5f 6c 61 72 67 65 5f 73 79 |0.alloc_large_sy|
000009c0 73 74 65 6d 5f 68 61 73 68 3a 20 61 64 61 70 74 |stem_hash: adapt|
000009d0 20 30 0a 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d | 0.=============|
000009e0 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |================|
*
00000a20 3d 3d 3d 0a 55 42 53 41 4e 3a 20 55 6e 64 65 66 |===.UBSAN: Undef|
00000a30 69 6e 65 64 20 62 65 68 61 76 69 6f 75 72 20 69 |ined behaviour i|
00000a40 6e 20 2e 2e 2f 6d 6d 2f 70 61 67 65 5f 61 6c 6c |n ../mm/page_all|
00000a50 6f 63 2e 63 3a 37 32 32 31 3a 31 30 0a 73 69 67 |oc.c:7221:10.sig|
00000a60 6e 65 64 20 69 6e 74 65 67 65 72 20 6f 76 65 72 |ned integer over|
00000a70 66 6c 6f 77 3a 0a 32 31 34 37 34 38 33 36 34 37 |flow:.2147483647|
00000a80 20 2b 20 31 20 63 61 6e 6e 6f 74 20 62 65 20 72 | + 1 cannot be r|
00000a90 65 70 72 65 73 65 6e 74 65 64 20 69 6e 20 74 79 |epresented in ty|
00000aa0 70 65 20 27 69 6e 74 20 5b 34 5d 27 0a 43 50 55 |pe 'int [4]'.CPU|
00000ab0 3a 20 30 20 50 49 44 3a 20 30 20 43 6f 6d 6d 3a |: 0 PID: 0 Comm:|
00000ac0 20 73 77 61 70 70 65 72 20 4e 6f 74 20 74 61 69 | swapper Not tai|
00000ad0 6e 74 65 64 20 34 2e 31 32 2e 30 2d 72 63 31 2d |nted 4.12.0-rc1-|
00000ae0 67 63 63 2d 36 2e 33 2e 31 2d 30 30 31 38 32 2d |gcc-6.3.1-00182-|
00000af0 67 36 37 64 30 36 38 37 32 32 34 61 39 2d 64 69 |g67d0687224a9-di|
00000b00 72 74 79 20 23 38 0a 43 61 6c 6c 20 54 72 61 63 |rty #8.Call Trac|
00000b10 65 3a 0a 5b 63 30 65 30 35 65 61 30 5d 20 5b 63 |e:.[c0e05ea0] [c|
00000b20 30 34 37 38 38 63 34 5d 20 75 62 73 61 6e 5f 65 |04788c4] ubsan_e|
00000b30 70 69 6c 6f 67 75 65 2b 30 78 31 38 2f 30 78 34 |pilogue+0x18/0x4|
00000b40 63 20 28 75 6e 72 65 6c 69 61 62 6c 65 29 0a 5b |c (unreliable).[|
00000b50 63 30 65 30 35 65 62 30 5d 20 5b 63 30 34 37 39 |c0e05eb0] [c0479|
00000b60 32 36 30 5d 20 68 61 6e 64 6c 65 5f 6f 76 65 72 |260] handle_over|
00000b70 66 6c 6f 77 2b 30 78 62 63 2f 30 78 64 63 0a 5b |flow+0xbc/0xdc.[|
00000b80 63 30 65 30 35 66 33 30 5d 20 5b 63 30 61 62 39 |c0e05f30] [c0ab9|
00000b90 38 66 38 5d 20 61 6c 6c 6f 63 5f 6c 61 72 67 65 |8f8] alloc_large|
00000ba0 5f 73 79 73 74 65 6d 5f 68 61 73 68 2b 30 78 65 |_system_hash+0xe|
00000bb0 34 2f 30 78 35 65 63 0a 5b 63 30 65 30 35 66 39 |4/0x5ec.[c0e05f9|
00000bc0 30 5d 20 5b 63 30 61 62 65 30 30 30 5d 20 76 66 |0] [c0abe000] vf|
00000bd0 73 5f 63 61 63 68 65 73 5f 69 6e 69 74 5f 65 61 |s_caches_init_ea|
00000be0 72 6c 79 2b 30 78 34 63 2f 30 78 36 34 0a 5b 63 |rly+0x4c/0x64.[c|
00000bf0 30 65 30 35 66 62 30 5d 20 5b 63 30 61 61 35 32 |0e05fb0] [c0aa52|
00000c00 31 38 5d 20 73 74 61 72 74 5f 6b 65 72 6e 65 6c |18] start_kernel|
00000c10 2b 30 78 32 33 63 2f 30 78 33 63 34 0a 5b 63 30 |+0x23c/0x3c4.[c0|
00000c20 65 30 35 66 66 30 5d 20 5b 30 30 30 30 33 34 34 |e05ff0] [0000344|
00000c30 63 5d 20 30 78 33 34 34 63 0a 3d 3d 3d 3d 3d 3d |c] 0x344c.======|
00000c40 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d 3d |================|
cheers
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