RE: Linux and huge pages
From: Yong Huang <yong321_at_yahoo.com>
Date: Thu, 24 Jan 2013 07:42:54 -0800 (PST)
Message-ID: <1359042174.25380.YahooMailClassic_at_web184805.mail.gq1.yahoo.com>
> Unfortunately, if you're looking to directly confirm whether a
> particular memory segment was allocated with hugepages, I know of
> no way to do that.
Date: Thu, 24 Jan 2013 07:42:54 -0800 (PST)
Message-ID: <1359042174.25380.YahooMailClassic_at_web184805.mail.gq1.yahoo.com>
> Unfortunately, if you're looking to directly confirm whether a
> particular memory segment was allocated with hugepages, I know of
> no way to do that.
There's no v$ or x$ table for this info, but /proc/<pid>/smaps has KernelPageSize and MMUPageSize if your kernel is new enough, probably 2.6.29 or newer. For example, the following shows a shared memory segment of about 37GB using 2MB page size of HugePages.
70000000-960000000 rwxs 00000000 00:0c 1179654 /SYSV00000000 (deleted) Size: 37486592 kB Rss: 0 kB Pss: 0 kB Shared_Clean: 0 kB Shared_Dirty: 0 kB Private_Clean: 0 kB Private_Dirty: 0 kB Referenced: 0 kB Anonymous: 0 kB AnonHugePages: 0 kB Swap: 0 kB KernelPageSize: 2048 kB MMUPageSize: 2048 kB
Regarding the kernel version, my note says "[when] this patch is in your kernel: http://lkml.org/lkml/2008/10/3/250. That patch may be in kernel 2.6.29 (http://www.kernel.org/pub/linux/kernel/v2.6/)".
Yong Huang
-- http://www.freelists.org/webpage/oracle-lReceived on Thu Jan 24 2013 - 16:42:54 CET