Re: [alsa-devel] change kmalloc into vmalloc for large memory allocations

From: Lars-Peter Clausen
Date: Mon Mar 03 2014 - 06:34:28 EST


On 03/03/2014 12:13 PM, Wang, Yalin wrote:
Hi


I add logs in kernel , the result is :

532 <4>[ 5.690094] @@ sizeof(struct snd_soc_pcm_runtime)=1488 card->num_links=42 card->num_aux_devs=0

card->num_links=42 , is it correct ?

Very unlikely. Make sure that it is properly initialized in your machine driver.


our hardware is qcom msm8x26 platform .

This one doesn't seem to be in upstream.


Thanks

-----Original Message-----
From: Takashi Iwai [mailto:tiwai@xxxxxxx]
Sent: Monday, March 03, 2014 5:23 PM
To: Wang, Yalin
Cc: 'linux-kernel@xxxxxxxxxxxxxxx'; Mark Brown; 'perex@xxxxxxxx'; 'alsa-devel@xxxxxxxxxxxxxxxx'; Liam Girdwood
Subject: Re: change kmalloc into vmalloc for large memory allocations

At Mon, 03 Mar 2014 10:19:58 +0100,
Takashi Iwai wrote:

[Dropped unrelated subsystem MLs, and corrected Liam's address]

Grrr, even Mark's address was obsoleted. Here corrected.


Takashi


At Mon, 3 Mar 2014 09:55:15 +0800,
Wang, Yalin wrote:

Hi Takashi,

For this one:
https://git.kernel.org/cgit/linux/kernel/git/will/linux.git/tree/sou
nd/soc/soc-core.c?h=master#n3772

in my kernel log,
the allocation size 62496,
about 62KB,

This looks way too much than expected. I thought each struct
snd_soc_pcm_runtime should be 1 or 2kB. The code allocating an arary
of snd_soc_pcm_runtime, so this might be due to some invalid values
there.

I think need to change to vmalloc .
How do you think of it ?

This looks rather like a bug somewhere around it.

Could you check the values there, sizeof(struct snd_soc_pcm_runtime),
card->num_links and card->num_aux_devs?

And, with which hardware is the issue examined?


thanks,

Takashi


Logs:
<4>[ 11.469789] ------------[ cut here ]------------
<4>[ 11.469803] WARNING: at /media/00DE7FE2DE7FCE82/jb-mr2-yukon/kernel/include/linux/slub_def.h:265 __kmalloc+0x38/0x29c()
<4>[ 11.469811] size=62496 flags=80d0
<4>[ 11.469815] Modules linked in:
<4>[ 11.469835] [<c010c534>] (unwind_backtrace+0x0/0x11c) from [<c018ab04>] (warn_slowpath_common+0x4c/0x64)
<4>[ 11.469850] [<c018ab04>] (warn_slowpath_common+0x4c/0x64) from [<c018ab9c>] (warn_slowpath_fmt+0x2c/0x3c)
<4>[ 11.469864] [<c018ab9c>] (warn_slowpath_fmt+0x2c/0x3c) from [<c0249ab4>] (__kmalloc+0x38/0x29c)
<4>[ 11.469879] [<c0249ab4>] (__kmalloc+0x38/0x29c) from [<c06a0124>] (snd_soc_register_card+0x184/0x104c)
<4>[ 11.469896] [<c06a0124>] (snd_soc_register_card+0x184/0x104c) from [<c088183c>] (msm8226_asoc_machine_probe+0x298/0x7f0)
<4>[ 11.469913] [<c088183c>] (msm8226_asoc_machine_probe+0x298/0x7f0) from [<c044b1fc>] (platform_drv_probe+0x14/0x18)
<4>[ 11.469927] [<c044b1fc>] (platform_drv_probe+0x14/0x18) from [<c0449f2c>] (driver_probe_device+0x134/0x334)
<4>[ 11.469940] [<c0449f2c>] (driver_probe_device+0x134/0x334) from [<c044a194>] (__driver_attach+0x68/0x8c)
<4>[ 11.469953] [<c044a194>] (__driver_attach+0x68/0x8c) from [<c044849c>] (bus_for_each_dev+0x48/0x80)
<4>[ 11.469965] [<c044849c>] (bus_for_each_dev+0x48/0x80) from [<c0449528>] (bus_add_driver+0x100/0x26c)
<4>[ 11.469978] [<c0449528>] (bus_add_driver+0x100/0x26c) from [<c044a66c>] (driver_register+0x9c/0x120)
<4>[ 11.469992] [<c044a66c>] (driver_register+0x9c/0x120) from [<c010052c>] (do_one_initcall+0x90/0x160)
<4>[ 11.470007] [<c010052c>] (do_one_initcall+0x90/0x160) from [<c0d00b74>] (kernel_init+0xec/0x1a8)
<4>[ 11.470022] [<c0d00b74>] (kernel_init+0xec/0x1a8) from [<c0106aec>] (kernel_thread_exit+0x0/0x8)
<4>[ 11.470030] ---[ end trace 1b75b31a2719ed4d ]---

BRs/ Yalin
-----Original Message-----
From: Takashi Iwai [mailto:tiwai@xxxxxxx]
Sent: Friday, February 28, 2014 10:20 PM
To: Wang, Yalin
Cc: 'linux-kernel@xxxxxxxxxxxxxxx'; 'linux-arm-msm@xxxxxxxxxxxxxxx'; 'linux-arm-kernel@xxxxxxxxxxxxxxxxxxx'; 'linux-input@xxxxxxxxxxxxxxx'; 'balbi@xxxxxx'; 'gregkh@xxxxxxxxxxxxxxxxxxx'; 'lrg@xxxxxx'; 'broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx'; 'perex@xxxxxxxx'; 'pablo@xxxxxxxxxxxxx'; 'kaber@xxxxxxxxx'; 'davem@xxxxxxxxxxxxx'; 'rostedt@xxxxxxxxxxx'; 'fweisbec@xxxxxxxxx'; 'mingo@xxxxxxxxxx'; 'dmitry.torokhov@xxxxxxxxx'; 'rydberg@xxxxxxxxxxx'; 'linux-usb@xxxxxxxxxxxxxxx'; 'alsa-devel@xxxxxxxxxxxxxxxx'; 'netfilter-devel@xxxxxxxxxxxxxxx'; 'netfilter@xxxxxxxxxxxxxxx'; 'coreteam@xxxxxxxxxxxxx'; 'netdev@xxxxxxxxxxxxxxx'
Subject: Re: change kmalloc into vmalloc for large memory
allocations

At Fri, 28 Feb 2014 16:15:23 +0800,
Wang, Yalin wrote:

Hi


I find there is some drivers use kmalloc to allocate large Memorys
during module_init, some can be changed to use vmalloc To save
some low mem, I add log in kernel to track , And list them here:

https://git.kernel.org/cgit/linux/kernel/git/will/linux.git/tree/d
rive
rs/usb/gadget/f_mass_storage.c?h=master#n2724

https://git.kernel.org/cgit/linux/kernel/git/will/linux.git/tree/s
ound
/soc/soc-core.c?h=master#n3772

At least the ASoC runtime case doesn't use the allocated memory as buffer, and they are allocated only once per device, thus it shouldn't be the problem you stated. If it really consumes so much memory, we need to rethink, instead of allocating an array but allocate each object, for example.


thanks,

Takashi


https://git.kernel.org/cgit/linux/kernel/git/will/linux.git/tree/n
et/n
etfilter/nf_conntrack_ftp.c?h=master#n603
https://git.kernel.org/cgit/linux/kernel/git/will/linux.git/tree/n
et/n
etfilter/nf_conntrack_h323_main.c?h=master#n1849
https://git.kernel.org/cgit/linux/kernel/git/will/linux.git/tree/n
et/n
etfilter/nf_conntrack_irc.c?h=master#n247
https://git.kernel.org/cgit/linux/kernel/git/will/linux.git/tree/n
et/n
etfilter/nf_conntrack_sane.c?h=master#n195

https://git.kernel.org/cgit/linux/kernel/git/will/linux.git/tree/d
rive
rs/input/evdev.c?h=master#n403


they allocate large memory from 10k~64K , this will use lots of
low mem, instead if we use vmalloc for these drivers , it will be
good for some devices like smart phone, we often encounter some
errors like kmalloc failed because there is not enough low mem ,
especially when the device has physical memory less than 1GB .


could this module change the memory allocation into vmalloc ?

I was thinking that if we can introduce a helper function in kmalloc.h like this :

Kmalloc(size, flags)
{
If (size > PAGE_SIZE && flags&CAN_USE_VMALLOC_FLAG)
return vmalloc(size);
Else
return real_kmalloc(size);
}

Kfree(ptr)
{
If (is_vmalloc_addr(ptr))
Vfree(ptr);
Else
Kfree(ptr);
}


But we need add some flags to ensure always use kmalloc for Some
special use (dma etc..)

How do you think of it ?

Thanks




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