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Date: Wed, 08 Apr 2015 14:16:05 -0700 From: Mike Kravetz <mike.kravetz@...cle.com> To: Shawn Bohrer <shawn.bohrer@...il.com>, linux-mm@...ck.org CC: linux-kernel@...r.kernel.org Subject: Re: HugePages_Rsvd leak On 04/08/2015 09:15 AM, Shawn Bohrer wrote: > I've noticed on a number of my systems that after shutting down my > application that uses huge pages that I'm left with some pages still > in HugePages_Rsvd. It is possible that I still have something using > huge pages that I'm not aware of but so far my attempts to find > anything using huge pages have failed. I've run some simple tests > using map_hugetlb.c from the kernel source and can see that pages that > have been reserved but not allocated still show up in > /proc/<pid>/smaps and /proc/<pid>/numa_maps. Are there any cases > where this is not true? Just a quick question. Are you using hugetlb filesystem(s)? If so, you might want to take a look at files residing in the filesystem(s). As an experiment, I had a program do a simple mmap() of a file in a hugetlb filesystem. The program just created the mapping, and did not actually fault/allocate any huge pages. The result was the reservation (HugePages_Rsvd) of sufficient huge pages to cover the mapping. When the program exited, the reservations remained. If I remove (unlink) the file the reservations will be removed. -- Mike Kravetz -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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