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From: Andrew Morton <akpm@linux-foundation.org>
To: Mina Almasry <almasrymina@google.com>
Cc: Ken Chen <kenchen@google.com>,
	Mike Kravetz <mike.kravetz@oracle.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Chris Kennelly <ckennelly@google.com>
Subject: Re: [PATCH v1] mm, hugepages: add mremap() support for hugepage backed vma
Date: Sun, 1 Aug 2021 12:49:17 -0700	[thread overview]
Message-ID: <20210801124917.ca6fce3972866dc738bfcb7b@linux-foundation.org> (raw)
In-Reply-To: <20210730221522.524256-1-almasrymina@google.com>

On Fri, 30 Jul 2021 15:15:22 -0700 Mina Almasry <almasrymina@google.com> wrote:

> Support mremap() for hugepage backed vma segment by simply repositioning
> page table entries. The page table entries are repositioned to the new
> virtual address on mremap().
> 
> Hugetlb mremap() support is of course generic; my motivating use case
> is a library (hugepage_text), which reloads the ELF text of executables
> in hugepages. This significantly increases the execution performance of
> said executables.
> 
> Restricts the mremap operation on hugepages to up to the size of the
> original mapping as the underlying hugetlb reservation is not yet
> capable of handling remapping to a larger size.
> 
> Tested with a simple mmap/mremap test case, roughly:
> 
> void* haddr = mmap(NULL, size, PROT_READ | PROT_WRITE | PROT_EXEC,
> 		MAP_ANONYMOUS | MAP_SHARED, -1, 0);
> 
> void* taddr = mmap(NULL, size, PROT_NONE,
> 		MAP_HUGETLB | MAP_ANONYMOUS | MAP_SHARED, -1, 0);
> 
> void* raddr = mremap(haddr, size, size, MREMAP_MAYMOVE | MREMAP_FIXED, taddr);

Could we please get testing for this added into tools/testing/selftests/?

  reply	other threads:[~2021-08-01 19:49 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-30 22:15 Mina Almasry
2021-08-01 19:49 ` Andrew Morton [this message]
2021-08-01 23:12   ` Mina Almasry
2021-08-02 23:50 ` Mike Kravetz
2021-08-04 18:03   ` Mina Almasry
2021-08-05 16:56     ` Mike Kravetz
2021-08-11  0:52     ` Mina Almasry

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