Re: 4.14-rc2 on thinkpad x220: out of memory when inserting mmc card

[Pavel Machek]

Hi!

> The memory allocation used to be optional but became mandatory with:
> 
>   commit 304419d8a7e9204c5d19b704467b814df8c8f5b1
>   Author: Linus Walleij <linus.walleij@xxxxxxxxxx>
>   Date:   Thu May 18 11:29:32 2017 +0200
> 
>       mmc: core: Allocate per-request data using the block layer core
> 
> There is also a bug in mmc_init_request() where it doesn't free it's
> allocations on the error path, so you might want to check if you are leaking
> memory.

At this point, I don't really care about memory leaks.

But allocating 64KiB, and expecting the allocation to work is quite a
big no-no. Does code need to switch to vmalloc or something?

> Bounce buffers are being removed from v4.15 although you may experience
> performance regression with that:
> 
> 	https://marc.info/?l=linux-mmc&m=150589778700551

Hmm. The performance of this is already pretty bad, I really hope it
does not get any worse.

								Pavel

> 
> 
> On 01/10/17 13:57, Tetsuo Handa wrote:
> > Pavel Machek wrote:
> >> Hi!
> >>
> >>> I inserted u-SD card, only to realize that it is not detected as it
> >>> should be. And dmesg indeed reveals:
> >>
> >> Tetsuo asked me to report this to linux-mm.
> >>
> >> But 2^4 is 16 pages, IIRC that can't be expected to work reliably, and
> >> thus this sounds like MMC bug, not mm bug.
> > 
> > Yes, 16 pages is costly allocations which will fail without invoking the
> > OOM killer. But I thought this is an interesting case, for mempool
> > allocation should be able to handle memory allocation failure except
> > initial allocations, and initial allocation is failing.
> > 
> > I think that using kvmalloc() (and converting corresponding kfree() to
> > kvfree()) will make initial allocations succeed, but that might cause
> > needlessly succeeding subsequent mempool allocations under memory pressure?
> > 
> >>
> >>> [10994.299846] mmc0: new high speed SDHC card at address 0003
> >>> [10994.302196] kworker/2:1: page allocation failure: order:4,
> >>> mode:0x16040c0(GFP_KERNEL|__GFP_COMP|__GFP_NOTRACK), nodemask=(null)
> >>> [10994.302212] CPU: 2 PID: 9500 Comm: kworker/2:1 Not tainted
> >>> 4.14.0-rc2 #135
> >>> [10994.302215] Hardware name: LENOVO 42872WU/42872WU, BIOS 8DET73WW
> >>> (1.43 ) 10/12/2016
> >>> [10994.302222] Workqueue: events_freezable mmc_rescan
> >>> [10994.302227] Call Trace:
> >>> [10994.302233]  dump_stack+0x4d/0x67
> >>> [10994.302239]  warn_alloc+0xde/0x180
> >>> [10994.302243]  __alloc_pages_nodemask+0xaa4/0xd30
> >>> [10994.302249]  ? cache_alloc_refill+0xb73/0xc10
> >>> [10994.302252]  cache_alloc_refill+0x101/0xc10
> >>> [10994.302258]  ? mmc_init_request+0x2d/0xd0
> >>> [10994.302262]  ? mmc_init_request+0x2d/0xd0
> >>> [10994.302265]  __kmalloc+0xaf/0xe0
> >>> [10994.302269]  mmc_init_request+0x2d/0xd0
> >>> [10994.302273]  alloc_request_size+0x45/0x60
> >>> [10994.302276]  ? free_request_size+0x30/0x30
> >>> [10994.302280]  mempool_create_node+0xd7/0x130
> >>> [10994.302283]  ? alloc_request_simple+0x20/0x20
> >>> [10994.302287]  blk_init_rl+0xe8/0x110
> >>> [10994.302290]  blk_init_allocated_queue+0x70/0x180
> >>> [10994.302294]  mmc_init_queue+0xdd/0x370
> >>> [10994.302297]  mmc_blk_alloc_req+0xf6/0x340
> >>> [10994.302301]  mmc_blk_probe+0x18b/0x4e0
> >>> [10994.302305]  mmc_bus_probe+0x12/0x20
> >>> [10994.302309]  driver_probe_device+0x2f4/0x490
> >>>
> >>> Order 4 allocations are not supposed to be reliable...
> >>>
> >>> Any ideas?
> >>>
> >>> Thanks,
> >>> 									Pavel
> >>>
> >>
> >>
> >>
> >> -- 
> >> (english) http://www.livejournal.com/~pavelmachek
> >> (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
> > 

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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