]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
mm: huge_memory: a new debugfs interface for splitting THP tests
authorZi Yan <ziy@nvidia.com>
Wed, 5 May 2021 01:34:23 +0000 (18:34 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 5 May 2021 18:27:21 +0000 (11:27 -0700)
commitfa6c02315f745f00b62c634b220c3fb5c3310258
tree77c87e64af6aedd3a425c126f642dc77cfc035fa
parent75f83783bfdf2ddb3ffbf79ba44d506fb5b5548f
mm: huge_memory: a new debugfs interface for splitting THP tests

We did not have a direct user interface of splitting the compound page
backing a THP and there is no need unless we want to expose the THP
implementation details to users.  Make <debugfs>/split_huge_pages accept a
new command to do that.

By writing "<pid>,<vaddr_start>,<vaddr_end>" to
<debugfs>/split_huge_pages, THPs within the given virtual address range
from the process with the given pid are split. It is used to test
split_huge_page function. In addition, a selftest program is added to
tools/testing/selftests/vm to utilize the interface by splitting
PMD THPs and PTE-mapped THPs.

This does not change the old behavior, i.e., writing 1 to the interface
to split all THPs in the system.

Link: https://lkml.kernel.org/r/20210331235309.332292-1-zi.yan@sent.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mika Penttila <mika.penttila@nextfour.com>
Cc: Sandipan Das <sandipan@linux.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/huge_memory.c
tools/testing/selftests/vm/.gitignore
tools/testing/selftests/vm/Makefile
tools/testing/selftests/vm/split_huge_page_test.c [new file with mode: 0644]