On 01/09/23 12:38, Sergey Senozhatsky wrote: > Hi, > > This turns hard coded limit on maximum number of physical > pages per-zspage into a config option. It also increases the default > limit from 4 to 8. > > Sergey Senozhatsky (4): > zsmalloc: rework zspage chain size selection > zsmalloc: skip chain size calculation for pow_of_2 classes > zsmalloc: make zspage chain size configurable > zsmalloc: set default zspage chain size to 8 > > Documentation/mm/zsmalloc.rst | 168 ++++++++++++++++++++++++++++++++++ > mm/Kconfig | 19 ++++ > mm/zsmalloc.c | 72 +++++---------- > 3 files changed, 212 insertions(+), 47 deletions(-) Hi Sergey, The following BUG shows up after this series in linux-next. I can easily recreate by doing the following: # echo large_value > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages where 'large_value' is a so big that there could never possibly be that many 2MB huge pages in the system. -- Mike Kravetz [ 22.981684] ------------[ cut here ]------------ [ 22.982990] kernel BUG at mm/zsmalloc.c:1982! [ 22.984204] invalid opcode: 0000 [#1] PREEMPT SMP PTI [ 22.985561] CPU: 0 PID: 41 Comm: kcompactd0 Not tainted 6.2.0-rc3+ #13 [ 22.987430] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.1-2.fc37 04/01/2014 [ 22.989728] RIP: 0010:zs_page_migrate+0x43c/0x490 [ 22.991070] Code: c7 c6 c8 f6 21 82 e8 b3 73 f6 ff 0f 0b 0f 1f 44 00 00 e9 20 fd ff ff 0f 1f 44 00 00 e9 9e fd ff ff 48 83 ef 01 e9 6b fe ff ff <0f> 0b 48 8b 43 20 49 89 45 20 e9 ff fd ff ff 48 c7 c6 60 d3 1d 82 [ 22.995900] RSP: 0018:ffffc9000121fb20 EFLAGS: 00010246 [ 22.997364] RAX: 0000000000000002 RBX: ffffea0005b8b380 RCX: 0000000000000000 [ 22.999299] RDX: 0000000000000002 RSI: ffffffff81e28a62 RDI: 00000000ffffffff [ 23.001236] RBP: ffff88816e2cf000 R08: ffffea0005b8b340 R09: 0000000000000008 [ 23.003181] R10: ffff88827fffafe0 R11: 0000000000280000 R12: ffff88816e2cf400 [ 23.005038] R13: ffffea0009e7f800 R14: ffff88817d783880 R15: ffff8881036a44d8 [ 23.006921] FS: 0000000000000000(0000) GS:ffff888277c00000(0000) knlGS:0000000000000000 [ 23.009116] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 23.010732] CR2: 00007f8b14e20550 CR3: 0000000103026004 CR4: 0000000000370ef0 [ 23.013978] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 23.015931] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 23.017892] Call Trace: [ 23.018664] <TASK> [ 23.019345] move_to_new_folio+0x14d/0x1f0 [ 23.020710] migrate_pages+0xe36/0x1240 [ 23.021895] ? __pfx_compaction_alloc+0x10/0x10 [ 23.023202] ? _raw_write_lock+0x13/0x30 [ 23.024335] ? __pfx_compaction_free+0x10/0x10 [ 23.025608] ? isolate_movable_page+0xff/0x250 [ 23.026880] compact_zone+0x9da/0xdf0 [ 23.027990] kcompactd_do_work+0x1d2/0x2c0 [ 23.029180] kcompactd+0x220/0x3e0 [ 23.030166] ? __pfx_autoremove_wake_function+0x10/0x10 [ 23.031612] ? __pfx_kcompactd+0x10/0x10 [ 23.032706] kthread+0xe6/0x110 [ 23.033648] ? __pfx_kthread+0x10/0x10 [ 23.034704] ret_from_fork+0x29/0x50 [ 23.035734] </TASK> [ 23.036443] Modules linked in: rfkill ip6table_filter ip6_tables sunrpc snd_hda_codec_generic snd_hda_intel snd_intel_dspcfg snd_hda_codec snd_hwdep snd_hda_core snd_seq snd_seq_device 9p netfs snd_pcm joydev 9pnet_virtio virtio_balloon snd_timer snd soundcore 9pnet virtio_blk virtio_net net_failover failover virtio_console crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel serio_raw virtio_pci virtio virtio_pci_legacy_dev virtio_pci_modern_dev virtio_ring fuse [ 23.049869] ---[ end trace 0000000000000000 ]--- [ 23.051154] RIP: 0010:zs_page_migrate+0x43c/0x490 [ 23.052466] Code: c7 c6 c8 f6 21 82 e8 b3 73 f6 ff 0f 0b 0f 1f 44 00 00 e9 20 fd ff ff 0f 1f 44 00 00 e9 9e fd ff ff 48 83 ef 01 e9 6b fe ff ff <0f> 0b 48 8b 43 20 49 89 45 20 e9 ff fd ff ff 48 c7 c6 60 d3 1d 82 [ 23.057413] RSP: 0018:ffffc9000121fb20 EFLAGS: 00010246 [ 23.058892] RAX: 0000000000000002 RBX: ffffea0005b8b380 RCX: 0000000000000000 [ 23.060867] RDX: 0000000000000002 RSI: ffffffff81e28a62 RDI: 00000000ffffffff [ 23.062835] RBP: ffff88816e2cf000 R08: ffffea0005b8b340 R09: 0000000000000008 [ 23.064825] R10: ffff88827fffafe0 R11: 0000000000280000 R12: ffff88816e2cf400 [ 23.066806] R13: ffffea0009e7f800 R14: ffff88817d783880 R15: ffff8881036a44d8 [ 23.068738] FS: 0000000000000000(0000) GS:ffff888277c00000(0000) knlGS:0000000000000000 [ 23.071022] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 23.072579] CR2: 00007f8b14e20550 CR3: 0000000103026004 CR4: 0000000000370ef0 [ 23.076152] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 23.078172] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 23.080134] note: kcompactd0[41] exited with preempt_count 1
