[PATCH v2 0/2] khugepaged: collapse pmd for pte-mapped THP

From: Song Liu <songliubraving@fb.com>
To: <linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>,
	<akpm@linux-foundation.org>
Cc: <matthew.wilcox@oracle.com>, <kirill.shutemov@linux.intel.com>,
	<oleg@redhat.com>, <kernel-team@fb.com>,
	<william.kucharski@oracle.com>, <srikar@linux.vnet.ibm.com>,
	Song Liu <songliubraving@fb.com>
Subject: [PATCH v2 0/2] khugepaged: collapse pmd for pte-mapped THP
Date: Wed, 31 Jul 2019 11:33:29 -0700	[thread overview]
Message-ID: <20190731183331.2565608-1-songliubraving@fb.com> (raw)

Changes v1 => v2:
1. Call collapse_pte_mapped_thp() directly from uprobe_write_opcode();
2. Add VM_BUG_ON() for addr alignment in khugepaged_add_pte_mapped_thp()
   and collapse_pte_mapped_thp().

This set is the newer version of 5/6 and 6/6 of [1]. Newer version of
1-4 of the work [2] was recently picked by Andrew.

Patch 1 enables khugepaged to handle pte-mapped THP. These THPs are left
in such state when khugepaged failed to get exclusive lock of mmap_sem.

Patch 2 leverages work in 1 for uprobe on THP. After [2], uprobe only
splits the PMD. When the uprobe is disabled, we get pte-mapped THP.
After this set, these pte-mapped THP will be collapsed as pmd-mapped.

[1] https://lkml.org/lkml/2019/6/23/23
[2] https://www.spinics.net/lists/linux-mm/msg185889.html

Song Liu (2):
  khugepaged: enable collapse pmd for pte-mapped THP
  uprobe: collapse THP pmd after removing all uprobes

 include/linux/khugepaged.h |  12 ++++
 kernel/events/uprobes.c    |   9 +++
 mm/khugepaged.c            | 138 +++++++++++++++++++++++++++++++++++++
 3 files changed, 159 insertions(+)

--
2.17.1