From: Vlastimil Babka <vbabka@suse.cz>
To: John Thomson <lists@johnthomson.fastmail.com.au>,
Feng Tang <feng.tang@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Roman Gushchin <roman.gushchin@linux.dev>,
Hyeonggon Yoo <42.hyeyoo@gmail.com>,
Dmitry Vyukov <dvyukov@google.com>,
Jonathan Corbet <corbet@lwn.net>,
Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kasan-dev@googlegroups.com, Robin Murphy <robin.murphy@arm.com>,
John Garry <john.garry@huawei.com>,
Kefeng Wang <wangkefeng.wang@huawei.com>
Subject: Re: [PATCH v6 1/4] mm/slub: enable debugging memory wasting of kmalloc
Date: Sun, 30 Oct 2022 22:30:24 +0100 [thread overview]
Message-ID: <af2ba83d-c3f4-c6fb-794e-c2c7c0892c44@suse.cz> (raw)
In-Reply-To: <becf2ac3-2a90-4f3a-96d9-a70f67c66e4a@app.fastmail.com>
On 10/30/22 20:23, John Thomson wrote:
> On Tue, 13 Sep 2022, at 06:54, Feng Tang wrote:
>> kmalloc's API family is critical for mm, with one nature that it will
>> round up the request size to a fixed one (mostly power of 2). Say
>> when user requests memory for '2^n + 1' bytes, actually 2^(n+1) bytes
>> could be allocated, so in worst case, there is around 50% memory
>> space waste.
>
>
> I have a ralink mt7621 router running Openwrt, using the mips ZBOOT kernel, and appear to have bisected
> a very-nearly-clean kernel v6.1rc-2 boot issue to this commit.
> I have 3 commits atop 6.1-rc2: fix a ZBOOT compile error, use the Openwrt LZMA options,
> and enable DEBUG_ZBOOT for my platform. I am compiling my kernel within the Openwrt build system.
> No guarantees this is not due to something I am doing wrong, but any insight would be greatly appreciated.
>
>
> On UART, No indication of the (once extracted) kernel booting:
>
> transfer started ......................................... transfer ok, time=2.01s
> setting up elf image... OK
> jumping to kernel code
> zimage at: 80BA4100 810D4720
> Uncompressing Linux at load address 80001000
> Copy device tree to address 80B96EE0
> Now, booting the kernel...
It's weird that the commit would cause no output so early, SLUB code is
run only later.
> Nothing follows
>
> 6edf2576a6cc ("mm/slub: enable debugging memory wasting of kmalloc") reverted, normal boot:
> transfer started ......................................... transfer ok, time=2.01s
> setting up elf image... OK
> jumping to kernel code
> zimage at: 80BA4100 810D47A4
> Uncompressing Linux at load address 80001000
> Copy device tree to address 80B96EE0
> Now, booting the kernel...
>
> [ 0.000000] Linux version 6.1.0-rc2 (john@john) (mipsel-openwrt-linux-musl-gcc (OpenWrt GCC 11.3.0 r19724+16-1521d5f453) 11.3.0, GNU ld (GNU Binutils) 2.37) #0 SMP Fri Oct 28 03:48:10 2022
> [ 0.000000] SoC Type: MediaTek MT7621 ver:1 eco:3
> [ 0.000000] printk: bootconsole [early0] enabled
> [ 0.000000] CPU0 revision is: 0001992f (MIPS 1004Kc)
> [ 0.000000] MIPS: machine is MikroTik RouterBOARD 760iGS
> [ 0.000000] Initrd not found or empty - disabling initrd
> [ 0.000000] VPE topology {2,2} total 4
> [ 0.000000] Primary instruction cache 32kB, VIPT, 4-way, linesize 32 bytes.
> [ 0.000000] Primary data cache 32kB, 4-way, PIPT, no aliases, linesize 32 bytes
> [ 0.000000] MIPS secondary cache 256kB, 8-way, linesize 32 bytes.
> [ 0.000000] Zone ranges:
> [ 0.000000] Normal [mem 0x0000000000000000-0x000000000fffffff]
> [ 0.000000] HighMem empty
> [ 0.000000] Movable zone start for each node
> [ 0.000000] Early memory node ranges
> [ 0.000000] node 0: [mem 0x0000000000000000-0x000000000fffffff]
> [ 0.000000] Initmem setup node 0 [mem 0x0000000000000000-0x000000000fffffff]
> [ 0.000000] percpu: Embedded 11 pages/cpu s16064 r8192 d20800 u45056
> [ 0.000000] Built 1 zonelists, mobility grouping on. Total pages: 64960
> [ 0.000000] Kernel command line: console=ttyS0,115200 rootfstype=squashfs,jffs2
> [ 0.000000] Dentry cache hash table entries: 32768 (order: 5, 131072 bytes, linear)
> [ 0.000000] Inode-cache hash table entries: 16384 (order: 4, 65536 bytes, linear)
> [ 0.000000] Writing ErrCtl register=00019146
> [ 0.000000] Readback ErrCtl register=00019146
> [ 0.000000] mem auto-init: stack:off, heap alloc:off, heap free:off
> [ 0.000000] Memory: 246220K/262144K available (7455K kernel code, 628K rwdata, 1308K rodata, 3524K init, 245K bss, 15924K reserved, 0K cma-reserved, 0K highmem)
> [ 0.000000] SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
> [ 0.000000] rcu: Hierarchical RCU implementation.
>
>
> boot continues as expected
>
>
> possibly relevant config options:
> grep -E '(SLUB|SLAB)' .config
> # SLAB allocator options
> # CONFIG_SLAB is not set
> CONFIG_SLUB=y
> CONFIG_SLAB_MERGE_DEFAULT=y
> # CONFIG_SLAB_FREELIST_RANDOM is not set
> # CONFIG_SLAB_FREELIST_HARDENED is not set
> # CONFIG_SLUB_STATS is not set
> CONFIG_SLUB_CPU_PARTIAL=y
> # end of SLAB allocator options
> # CONFIG_SLUB_DEBUG is not set
Also not having CONFIG_SLUB_DEBUG enabled means most of the code the
patch/commit touches is not even active.
Could this be some miscompile or code layout change exposing some
different bug, hmm.
Is it any different if you do enable CONFIG_SLUB_DEBUG ?
Or change to CONFIG_SLAB? (that would be really weird if not)
>
> With this commit reverted: cpuinfo and meminfo
>
> system type : MediaTek MT7621 ver:1 eco:3
> machine : MikroTik RouterBOARD 760iGS
> processor : 0
> cpu model : MIPS 1004Kc V2.15
> BogoMIPS : 586.13
> wait instruction : yes
> microsecond timers : yes
> tlb_entries : 32
> extra interrupt vector : yes
> hardware watchpoint : yes, count: 4, address/irw mask: [0x0ffc, 0x0ffc, 0x0ffb, 0x0ffb]
> isa : mips1 mips2 mips32r1 mips32r2
> ASEs implemented : mips16 dsp mt
> Options implemented : tlb 4kex 4k_cache prefetch mcheck ejtag llsc pindexed_dcache userlocal vint perf_cntr_intr_bit cdmm perf
> shadow register sets : 1
> kscratch registers : 0
> package : 0
> core : 0
> VPE : 0
> VCED exceptions : not available
> VCEI exceptions : not available
>
> processor : 1
> cpu model : MIPS 1004Kc V2.15
> BogoMIPS : 586.13
> wait instruction : yes
> microsecond timers : yes
> tlb_entries : 32
> extra interrupt vector : yes
> hardware watchpoint : yes, count: 4, address/irw mask: [0x0ffc, 0x0ffc, 0x0ffb, 0x0ffb]
> isa : mips1 mips2 mips32r1 mips32r2
> ASEs implemented : mips16 dsp mt
> Options implemented : tlb 4kex 4k_cache prefetch mcheck ejtag llsc pindexed_dcache userlocal vint perf_cntr_intr_bit cdmm perf
> shadow register sets : 1
> kscratch registers : 0
> package : 0
> core : 0
> VPE : 1
> VCED exceptions : not available
> VCEI exceptions : not available
>
> processor : 2
> cpu model : MIPS 1004Kc V2.15
> BogoMIPS : 586.13
> wait instruction : yes
> microsecond timers : yes
> tlb_entries : 32
> extra interrupt vector : yes
> hardware watchpoint : yes, count: 4, address/irw mask: [0x0ffc, 0x0ffc, 0x0ffb, 0x0ffb]
> isa : mips1 mips2 mips32r1 mips32r2
> ASEs implemented : mips16 dsp mt
> Options implemented : tlb 4kex 4k_cache prefetch mcheck ejtag llsc pindexed_dcache userlocal vint perf_cntr_intr_bit cdmm perf
> shadow register sets : 1
> kscratch registers : 0
> package : 0
> core : 1
> VPE : 0
> VCED exceptions : not available
> VCEI exceptions : not available
>
> processor : 3
> cpu model : MIPS 1004Kc V2.15
> BogoMIPS : 586.13
> wait instruction : yes
> microsecond timers : yes
> tlb_entries : 32
> extra interrupt vector : yes
> hardware watchpoint : yes, count: 4, address/irw mask: [0x0ffc, 0x0ffc, 0x0ffb, 0x0ffb]
> isa : mips1 mips2 mips32r1 mips32r2
> ASEs implemented : mips16 dsp mt
> Options implemented : tlb 4kex 4k_cache prefetch mcheck ejtag llsc pindexed_dcache userlocal vint perf_cntr_intr_bit cdmm perf
> shadow register sets : 1
> kscratch registers : 0
> package : 0
> core : 1
> VPE : 1
> VCED exceptions : not available
> VCEI exceptions : not available
>
> MemTotal: 249744 kB
> MemFree: 211088 kB
> MemAvailable: 187364 kB
> Buffers: 0 kB
> Cached: 8824 kB
> SwapCached: 0 kB
> Active: 1104 kB
> Inactive: 8860 kB
> Active(anon): 1104 kB
> Inactive(anon): 8860 kB
> Active(file): 0 kB
> Inactive(file): 0 kB
> Unevictable: 0 kB
> Mlocked: 0 kB
> HighTotal: 0 kB
> HighFree: 0 kB
> LowTotal: 249744 kB
> LowFree: 211088 kB
> SwapTotal: 0 kB
> SwapFree: 0 kB
> Dirty: 0 kB
> Writeback: 0 kB
> AnonPages: 1192 kB
> Mapped: 2092 kB
> Shmem: 8824 kB
> KReclaimable: 1704 kB
> Slab: 9372 kB
> SReclaimable: 1704 kB
> SUnreclaim: 7668 kB
> KernelStack: 592 kB
> PageTables: 264 kB
> SecPageTables: 0 kB
> NFS_Unstable: 0 kB
> Bounce: 0 kB
> WritebackTmp: 0 kB
> CommitLimit: 124872 kB
> Committed_AS: 14676 kB
> VmallocTotal: 1040376 kB
> VmallocUsed: 2652 kB
> VmallocChunk: 0 kB
> Percpu: 272 kB
>
>
> Cheers,
>
next prev parent reply other threads:[~2022-10-30 21:30 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-13 6:54 [PATCH v6 0/4] mm/slub: some debug enhancements for kmalloc Feng Tang
2022-09-13 6:54 ` [PATCH v6 1/4] mm/slub: enable debugging memory wasting of kmalloc Feng Tang
2022-09-23 11:43 ` Vlastimil Babka
2022-09-24 7:08 ` Feng Tang
2022-10-30 19:23 ` John Thomson
2022-10-30 21:30 ` Vlastimil Babka [this message]
2022-10-31 2:36 ` Feng Tang
2022-10-31 10:05 ` John Thomson
2022-10-31 11:36 ` Hyeonggon Yoo
2022-10-31 11:42 ` Feng Tang
2022-11-01 0:18 ` John Thomson
2022-11-01 2:41 ` John Thomson
2022-11-01 7:57 ` Feng Tang
2022-11-01 9:20 ` John Thomson
2022-11-01 9:31 ` Hyeonggon Yoo
2022-11-01 10:33 ` John Thomson
2022-11-01 10:42 ` Hyeonggon Yoo
2022-11-01 13:55 ` Feng Tang
2022-11-01 19:39 ` John Thomson
2022-11-02 6:08 ` Feng Tang
2022-11-02 7:16 ` Hyeonggon Yoo
2022-11-03 7:18 ` Feng Tang
2022-11-03 7:45 ` John Thomson
2022-11-03 8:16 ` Feng Tang
2022-11-02 8:22 ` Vlastimil Babka
2022-11-03 5:54 ` Feng Tang
2022-11-03 8:33 ` Vlastimil Babka
2022-11-03 14:16 ` Feng Tang
2022-11-03 14:36 ` Hyeonggon Yoo
2022-11-03 16:57 ` Vlastimil Babka
2022-11-03 17:35 ` Vlastimil Babka
2022-11-04 3:52 ` Feng Tang
2022-09-13 6:54 ` [PATCH v6 2/4] mm/slub: only zero the requested size of buffer for kzalloc Feng Tang
2022-09-26 19:11 ` Andrey Konovalov
2022-09-26 20:15 ` Kees Cook
2022-09-27 1:22 ` Feng Tang
2022-09-27 2:42 ` Feng Tang
2022-10-13 14:00 ` Andrey Konovalov
2022-10-14 5:59 ` Feng Tang
2022-09-13 6:54 ` [PATCH v6 3/4] mm: kasan: Add free_meta size info in struct kasan_cache Feng Tang
2022-09-20 19:20 ` Andrey Konovalov
2022-09-21 12:02 ` Feng Tang
2022-09-24 18:05 ` Andrey Konovalov
2022-09-25 11:26 ` Feng Tang
2022-09-25 16:31 ` Andrey Konovalov
2022-09-27 3:03 ` Feng Tang
2022-09-13 6:54 ` [PATCH v6 4/4] mm/slub: extend redzone check to extra allocated kmalloc space than requested Feng Tang
2022-09-13 8:53 ` Hyeonggon Yoo
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=af2ba83d-c3f4-c6fb-794e-c2c7c0892c44@suse.cz \
--to=vbabka@suse.cz \
--cc=42.hyeyoo@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=andreyknvl@gmail.com \
--cc=cl@linux.com \
--cc=corbet@lwn.net \
--cc=dave.hansen@intel.com \
--cc=dvyukov@google.com \
--cc=feng.tang@intel.com \
--cc=iamjoonsoo.kim@lge.com \
--cc=john.garry@huawei.com \
--cc=kasan-dev@googlegroups.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=lists@johnthomson.fastmail.com.au \
--cc=penberg@kernel.org \
--cc=rientjes@google.com \
--cc=robin.murphy@arm.com \
--cc=roman.gushchin@linux.dev \
--cc=wangkefeng.wang@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).