Re: No, really, stop trying to delete slab until you've finished making slub perform as well
From: KOSAKI Motohiro
Date: Mon Aug 18 2008 - 06:10:26 EST
> Christoph Lameter wrote:
>
> > Setting remote_node_defrag_ratio to 100 will make slub always take the remote
> > slab instead of allocating a new one.
>
> As pointed out by Adrian D. off list:
>
> The max remote_node_defrag_ratio is 99.
>
> Maybe we need to change the comparison in remote_node_defrag_ratio_store() to
> allow 100 to switch off any node local allocs?
Hmmm,
it doesn't change any behavior.
I did ..
1. slub code change (see below)
Index: b/mm/slub.c
===================================================================
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4056,7 +4056,7 @@ static ssize_t remote_node_defrag_ratio_
if (err)
return err;
- if (ratio < 100)
+ if (ratio <= 100)
s->remote_node_defrag_ratio = ratio * 10;
return length;
2. change remote defrag ratio
# echo 100 > /sys/kernel/slab/:t-0000128/remote_node_defrag_ratio
# cat /sys/kernel/slab/:t-0000128/remote_node_defrag_ratio
100
3. ran hackbench
4. ./slabinfo
Name Objects Objsize Space Slabs/Part/Cpu O/S O %Fr %Ef Flg
:at-0000016 4096 16 65.5K 0/0/1 4096 0 0 100 *a
:at-0000024 21840 24 524.2K 0/0/8 2730 0 0 99 *a
:at-0000032 2048 32 65.5K 0/0/1 2048 0 0 100 *Aa
:at-0000088 4464 88 393.2K 0/0/6 744 0 0 99 *a
:at-0000096 5456 96 524.2K 0/0/8 682 0 0 99 *a
:t-0000016 32768 16 524.2K 0/0/8 4096 0 0 100 *
:t-0000024 21840 24 524.2K 0/0/8 2730 0 0 99 *
:t-0000032 34806 32 1.1M 9/1/8 2048 0 5 99 *
:t-0000040 14417 40 917.5K 6/6/8 1638 0 42 62 *
:t-0000048 5460 48 262.1K 0/0/4 1365 0 0 99 *
:t-0000064 10224 64 655.3K 2/1/8 1024 0 10 99 *
:t-0000072 29120 72 2.0M 26/0/6 910 0 0 99 *
:t-0000080 16376 80 1.3M 12/1/8 819 0 5 99 *
:t-0000096 5456 96 524.2K 0/0/8 682 0 0 99 *
:t-0000128 28917 128 1.3G 21041/21041/8 512 0 99 0 *
:t-0000256 15280 256 31.4M 472/436/8 256 0 90 12 *
:t-0000384 1360 352 524.2K 0/0/8 170 0 0 91 *A
:t-0000512 2388 512 1.3M 12/4/8 128 0 20 93 *
:t-0000768 851 768 851.9K 5/5/8 85 0 38 76 *A
:t-0000896 742 880 851.9K 5/4/8 73 0 30 76 *A
:t-0001024 1819 1024 15.1M 223/211/8 64 0 91 12 *
:t-0002048 2641 2048 17.9M 129/116/8 64 1 84 30 *
:t-0004096 817 4096 57.1M 210/210/8 64 2 96 5 *
anon_vma 10920 40 524.2K 0/0/8 1365 0 0 83
bdev_cache 256 1008 262.1K 0/0/4 64 0 0 98 Aa
blkdev_queue 140 1864 262.1K 0/0/2 70 1 0 99
blkdev_requests 1720 304 524.2K 0/0/8 215 0 0 99
buffer_head 7284 104 2.5M 31/30/8 585 0 76 29 a
cfq_io_context 3120 168 524.2K 0/0/8 390 0 0 99
cfq_queue 3848 136 524.2K 0/0/8 481 0 0 99
dentry 3775 224 2.5M 31/29/8 292 0 74 33 a
ext3_inode_cache 740 1016 2.4M 30/30/8 64 0 78 30 a
fat_inode_cache 77 840 65.5K 0/0/1 77 0 0 98 a
file_lock_cache 2616 192 524.2K 0/0/8 327 0 0 95
hugetlbfs_inode_cache 83 776 65.5K 0/0/1 83 0 0 98
idr_layer_cache 944 544 524.2K 0/0/8 118 0 0 97
inode_cache 1050 744 851.9K 5/1/8 87 0 7 91 a
kmalloc-16384 160 16384 2.6M 0/0/5 32 3 0 100
kmalloc-192 4578 192 87.5M 1328/1328/8 341 0 99 1
kmalloc-32768 128 32768 4.1M 0/0/8 16 3 0 100
kmalloc-65536 32 65536 2.0M 0/0/8 4 2 0 100
kmalloc-8 65536 8 524.2K 0/0/8 8192 0 0 100
kmalloc-8192 512 8192 4.1M 0/0/8 64 3 0 100
kmem_cache_node 3276 80 262.1K 0/0/4 819 0 0 99 *
mqueue_inode_cache 56 1064 65.5K 0/0/1 56 0 0 90 A
numa_policy 248 264 65.5K 0/0/1 248 0 0 99
proc_inode_cache 655 792 720.8K 3/3/8 81 0 27 71 a
radix_tree_node 1142 552 917.5K 6/6/8 117 0 42 68 a
shmem_inode_cache 1230 1000 1.3M 12/3/8 65 0 15 93
sighand_cache 434 1608 917.5K 6/4/8 39 0 28 76 A
sigqueue 3272 160 524.2K 0/0/8 409 0 0 99
sock_inode_cache 774 832 851.9K 5/3/8 73 0 23 75 Aa
TCP 144 1712 262.1K 0/0/4 36 0 0 94 A
vm_area_struct 4034 176 851.9K 5/5/8 372 0 38 83
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