diff options
author | Kefeng Wang <wangkefeng.wang@huawei.com> | 2024-04-22 06:00:39 +0300 |
---|---|---|
committer | Andrew Morton <akpm@linux-foundation.org> | 2024-05-06 03:53:43 +0300 |
commit | 6ed31ba3921162ef5d4f2f99b91681e8fd24ff34 (patch) | |
tree | d5965ed7c08ec0e2d280dd65a412673328f04f37 /fs/bfs | |
parent | 2d8b272cdcad17d9b875c206fbcb0422b791ab3a (diff) | |
download | linux-6ed31ba3921162ef5d4f2f99b91681e8fd24ff34.tar.xz |
mm: memory: check userfaultfd_wp() in vmf_orig_pte_uffd_wp()
Add userfaultfd_wp() check in vmf_orig_pte_uffd_wp() to avoid the
unnecessary FAULT_FLAG_ORIG_PTE_VALID check/pte_marker_entry_uffd_wp() in
most pagefault, note, the function vmf_orig_pte_uffd_wp() is not inlined
in the two kernel versions, the difference is shown below,
perf date,
perf report -i perf.data.before | grep vmf
0.17% 0.13% lat_pagefault [kernel.kallsyms] [k] vmf_orig_pte_uffd_wp.part.0.isra.0
perf report -i perf.data.after | grep vmf
lat_pagefault -W 5 -N 5 /tmp/XXX
latency before after diff
average(8 tests) 0.262675 0.2600375 -0.0026375
Although it's a small, but the uffd_wp is a new feature than previous
kernel, when the vma is not registered with UFFD_WP, let's avoid to
execute the new logical, also adding __always_inline attribute to
vmf_orig_pte_uffd_wp(), which make set_pte_range() only check VM_UFFD_WP
flags without the function call. In addition, directly call the
vmf_orig_pte_uffd_wp() in do_anonymous_page() and set_pte_range() to save
an uffd_wp variable.
Link: https://lkml.kernel.org/r/20240422030039.3293568-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'fs/bfs')
0 files changed, 0 insertions, 0 deletions