Messages in this thread | | | Subject | Re: [PATCH RFC] hugetlbfs 'noautofill' mount option | From | Prakash Sangappa <> | Date | Tue, 9 May 2017 13:59:34 -0700 |
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On 5/9/17 1:58 AM, Christoph Hellwig wrote: > On Mon, May 08, 2017 at 03:12:42PM -0700, prakash.sangappa wrote: >> Regarding #3 as a general feature, do we want to >> consider this and the complexity associated with the >> implementation? > We have to. Given that no one has exclusive access to hugetlbfs > a mount option is fundamentally the wrong interface.
A hugetlbfs filesystem may need to be mounted for exclusive use by an application. Note, recently the 'min_size' mount option was added to hugetlbfs, which would reserve minimum number of huge pages for that filesystem for use by an application. If the filesystem with min size specified, is not setup for exclusive use by an application, then the purpose of reserving huge pages is defeated. The min_size option was for use by applications like the database.
Also, I am investigating enabling hugetlbfs mounts within user namespace's mount namespace. That would allow an application to mount a hugetlbfs filesystem inside a namespace exclusively for its use, running as a non root user. For this it seems like the 'min_size' should be subject to some user limits. Anyways, mounting inside user namespaces is a different discussion.
So, if a filesystem has to be setup for exclusive use by an application, then different mount options can be used for that filesystem.
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