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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