Re: [PATCH] ext4: change the type of ext4 cache stats to percpu_counter to improve performance

From: Shaokun Zhang
Date: Mon Aug 26 2019 - 04:13:10 EST

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Hi Eric,

On 2019/8/26 1:28, Eric Biggers wrote:
> On Sat, Aug 24, 2019 at 11:25:24PM -0400, Theodore Y. Ts'o wrote:
>> On Fri, Aug 23, 2019 at 10:47:34AM +0800, Shaokun Zhang wrote:
>>> From: Yang Guo <guoyang2@xxxxxxxxxx>
>>>
>>> @es_stats_cache_hits and @es_stats_cache_misses are accessed frequently in
>>> ext4_es_lookup_extent function, it would influence the ext4 read/write
>>> performance in NUMA system.
>>> Let's optimize it using percpu_counter, it is profitable for the
>>> performance.
>>>
>>> The test command is as below:
>>> fio -name=randwrite -numjobs=8 -filename=/mnt/test1 -rw=randwrite
>>> -ioengine=libaio -direct=1 -iodepth=64 -sync=0 -norandommap -group_reporting
>>> -runtime=120 -time_based -bs=4k -size=5G
>>>
>>> And the result is better 10% than the initial implement:
>>> without the patchïIOPS=197k, BW=770MiB/s (808MB/s)(90.3GiB/120002msec)
>>> with the patch, IOPS=218k, BW=852MiB/s (894MB/s)(99.9GiB/120002msec)
>>>
>>> Cc: "Theodore Ts'o" <tytso@xxxxxxx>
>>> Cc: Andreas Dilger <adilger.kernel@xxxxxxxxx>
>>> Signed-off-by: Yang Guo <guoyang2@xxxxxxxxxx>
>>> Signed-off-by: Shaokun Zhang <zhangshaokun@xxxxxxxxxxxxx>
>>
>> Applied with some adjustments so it would apply. I also changed the patch summary to:
>>
>> ext4: use percpu_counters for extent_status cache hits/misses
>>
>> - Ted
>
> This patch is causing the following. Probably because there's no calls to
> percpu_counter_destroy() for the new counters?
>

Apologies, We missed it and let's fix it soon.

Thanks,
Shaokun

> ==================================================================
> BUG: KASAN: use-after-free in __list_del_entry_valid+0x168/0x180 lib/list_debug.c:51
> Read of size 8 at addr ffff888063168fa8 by task umount/611
>
> CPU: 1 PID: 611 Comm: umount Not tainted 5.3.0-rc4-00015-gcc08b68e62ec #6
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-20181126_142135-anatol 04/01/2014
> Call Trace:
> __dump_stack lib/dump_stack.c:77 [inline]
> dump_stack+0x86/0xca lib/dump_stack.c:113
> print_address_description+0x6e/0x2e7 mm/kasan/report.c:351
> __kasan_report.cold+0x1b/0x35 mm/kasan/report.c:482
> kasan_report+0x12/0x17 mm/kasan/common.c:612
> __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
> __list_del_entry_valid+0x168/0x180 lib/list_debug.c:51
> __list_del_entry include/linux/list.h:131 [inline]
> list_del include/linux/list.h:139 [inline]
> percpu_counter_destroy+0x5d/0x230 lib/percpu_counter.c:157
> ext4_put_super+0x319/0xbb0 fs/ext4/super.c:1010
> generic_shutdown_super+0x128/0x320 fs/super.c:458
> kill_block_super+0x97/0xe0 fs/super.c:1310
> deactivate_locked_super+0x7b/0xd0 fs/super.c:331
> deactivate_super+0x138/0x150 fs/super.c:362
> cleanup_mnt+0x298/0x3f0 fs/namespace.c:1102
> __cleanup_mnt+0xd/0x10 fs/namespace.c:1109
> task_work_run+0x103/0x180 kernel/task_work.c:113
> tracehook_notify_resume include/linux/tracehook.h:188 [inline]
> exit_to_usermode_loop+0x10b/0x130 arch/x86/entry/common.c:163
> prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
> syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
> do_syscall_64+0x343/0x450 arch/x86/entry/common.c:299
> entry_SYSCALL_64_after_hwframe+0x49/0xbe
> RIP: 0033:0x7f7caed23d77
> Code: 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 8
> RSP: 002b:00007ffe960e7c98 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
> RAX: 0000000000000000 RBX: 0000560c039e1060 RCX: 00007f7caed23d77
> RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000560c039e3c90
> RBP: 0000560c039e3c90 R08: 0000560c039e2ec0 R09: 0000000000000014
> R10: 00000000000006b4 R11: 0000000000000246 R12: 00007f7caf225e64
> R13: 0000000000000000 R14: 0000560c039e1240 R15: 00007ffe960e7f20
>
> Allocated by task 596:
> save_stack mm/kasan/common.c:69 [inline]
> set_track mm/kasan/common.c:77 [inline]
> __kasan_kmalloc.part.0+0x41/0xb0 mm/kasan/common.c:487
> __kasan_kmalloc.constprop.0+0xba/0xc0 mm/kasan/common.c:468
> kasan_kmalloc+0x9/0x10 mm/kasan/common.c:501
> kmem_cache_alloc_trace+0x11e/0x2e0 mm/slab.c:3550
> kmalloc include/linux/slab.h:552 [inline]
> kzalloc include/linux/slab.h:748 [inline]
> ext4_fill_super+0x111/0x80a0 fs/ext4/super.c:3610
> mount_bdev+0x286/0x350 fs/super.c:1283
> ext4_mount+0x10/0x20 fs/ext4/super.c:6007
> legacy_get_tree+0x101/0x1f0 fs/fs_context.c:661
> vfs_get_tree+0x86/0x2e0 fs/super.c:1413
> do_new_mount fs/namespace.c:2791 [inline]
> do_mount+0x1093/0x1b30 fs/namespace.c:3111
> ksys_mount+0x7d/0xd0 fs/namespace.c:3320
> __do_sys_mount fs/namespace.c:3334 [inline]
> __se_sys_mount fs/namespace.c:3331 [inline]
> __x64_sys_mount+0xb9/0x150 fs/namespace.c:3331
> do_syscall_64+0x8f/0x450 arch/x86/entry/common.c:296
> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>
> Freed by task 600:
> save_stack mm/kasan/common.c:69 [inline]
> set_track mm/kasan/common.c:77 [inline]
> __kasan_slab_free+0x127/0x1f0 mm/kasan/common.c:449
> kasan_slab_free+0xe/0x10 mm/kasan/common.c:457
> __cache_free mm/slab.c:3425 [inline]
> kfree+0xc1/0x1e0 mm/slab.c:3756
> ext4_put_super+0x78c/0xbb0 fs/ext4/super.c:1061
> generic_shutdown_super+0x128/0x320 fs/super.c:458
> kill_block_super+0x97/0xe0 fs/super.c:1310
> deactivate_locked_super+0x7b/0xd0 fs/super.c:331
> deactivate_super+0x138/0x150 fs/super.c:362
> cleanup_mnt+0x298/0x3f0 fs/namespace.c:1102
> __cleanup_mnt+0xd/0x10 fs/namespace.c:1109
> task_work_run+0x103/0x180 kernel/task_work.c:113
> tracehook_notify_resume include/linux/tracehook.h:188 [inline]
> exit_to_usermode_loop+0x10b/0x130 arch/x86/entry/common.c:163
> prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
> syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
> do_syscall_64+0x343/0x450 arch/x86/entry/common.c:299
> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>
> The buggy address belongs to the object at ffff888063168980
> which belongs to the cache kmalloc-4k of size 4096
> The buggy address is located 1576 bytes inside of
> 4096-byte region [ffff888063168980, ffff888063169980)
> The buggy address belongs to the page:
> page:ffffea00015acec0 refcount:1 mapcount:0 mapping:ffff88806d000900 index:0x0 compound_mapcount: 0
> flags: 0x100000000010200(slab|head)
> raw: 0100000000010200 ffffea00015b9f08 ffffea0001749e58 ffff88806d000900
> raw: 0000000000000000 ffff888063168980 0000000100000001
> page dumped because: kasan: bad access detected
>
> Memory state around the buggy address:
> ffff888063168e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff888063168f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>> ffff888063168f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ^
> ffff888063169000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff888063169080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ==================================================================
>
> .
>

Next message: Rafael J. Wysocki: "Re: [PATCH] tools/power turbostat: fix file descriptor leaks"
Previous message: Yuehaibing: "Re: [PATCH -next] rtc: pcf2127: Fix build error without CONFIG_WATCHDOG_CORE"
In reply to: Shaokun Zhang: "Re: [PATCH] ext4: change the type of ext4 cache stats to percpu_counter to improve performance"
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