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Date: Mon, 29 Jan 2024 11:35:09 -0800
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Message-ID: <20240129193512.123145-1-lokeshgidra@google.com>
Subject: [PATCH v2 0/3] per-vma locks in userfaultfd
From: Lokesh Gidra <lokeshgidra@google.com>
To: akpm@linux-foundation.org
Cc: lokeshgidra@google.com, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, 
	linux-kernel@vger.kernel.org, selinux@vger.kernel.org, surenb@google.com, 
	kernel-team@android.com, aarcange@redhat.com, peterx@redhat.com, 
	david@redhat.com, axelrasmussen@google.com, bgeffon@google.com, 
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	ngeoffray@google.com, timmurray@google.com, rppt@kernel.org
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Performing userfaultfd operations (like copy/move etc.) in critical
section of mmap_lock (read-mode) causes significant contention on the
lock when operations requiring the lock in write-mode are taking place
concurrently. We can use per-vma locks instead to significantly reduce
the contention issue.

Changes since v1 [1]:
- rebase patches on 'mm-unstable' branch

[1] https://lore.kernel.org/all/20240126182647.2748949-1-lokeshgidra@google.com/

Lokesh Gidra (3):
  userfaultfd: move userfaultfd_ctx struct to header file
  userfaultfd: protect mmap_changing with rw_sem in userfaulfd_ctx
  userfaultfd: use per-vma locks in userfaultfd operations

 fs/userfaultfd.c              |  86 ++++---------
 include/linux/userfaultfd_k.h |  75 ++++++++---
 mm/userfaultfd.c              | 229 ++++++++++++++++++++++------------
 3 files changed, 229 insertions(+), 161 deletions(-)

-- 
2.43.0.429.g432eaa2c6b-goog