Messages in this thread | | | Subject | Re: [PATCH v3] mlx4_core: allocate ICM memory in page size chunks | From | Tariq Toukan <> | Date | Tue, 22 May 2018 18:33:21 +0300 |
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On 18/05/2018 12:45 AM, Qing Huang wrote: > > > On 5/17/2018 2:14 PM, Eric Dumazet wrote: >> On 05/17/2018 01:53 PM, Qing Huang wrote: >>> When a system is under memory presure (high usage with fragments), >>> the original 256KB ICM chunk allocations will likely trigger kernel >>> memory management to enter slow path doing memory compact/migration >>> ops in order to complete high order memory allocations. >>> >>> When that happens, user processes calling uverb APIs may get stuck >>> for more than 120s easily even though there are a lot of free pages >>> in smaller chunks available in the system. >>> >>> Syslog: >>> ... >>> Dec 10 09:04:51 slcc03db02 kernel: [397078.572732] INFO: task >>> oracle_205573_e:205573 blocked for more than 120 seconds. >>> ... >>> >> NACK on this patch. >> >> You have been asked repeatedly to use kvmalloc() >> >> This is not a minor suggestion. >> >> Take a look >> athttps://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d8c13f2271ec5178c52fbde072ec7b562651ed9d >> > > Would you please take a look at how table->icm is being used in the mlx4 > driver? It's a meta data used for individual pointer variable referencing, > not as data frag or in/out buffer. It has no need for contiguous phy. > memory. > > Thanks. >
NACK.
This would cause a degradation when iterating the entries of table->icm. For example, in mlx4_table_get_range.
Thanks, Tariq
>> And you'll understand some people care about this. >> >> Strongly. >> >> Thanks. >> >
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