diff options
| author | Barry Song <v-songbaohua@oppo.com> | 2025-06-11 13:47:45 +0300 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-07-10 08:42:07 +0300 |
| commit | 4f8ba33bbdfc475fdc1ac5de6a93f5de93203ed5 (patch) | |
| tree | 13b53a24d3a652abd7eafeb39c3ca9188e71590b /include/linux | |
| parent | f822a9a81a31311d67f260aea96005540b18ab07 (diff) | |
| download | linux-4f8ba33bbdfc475fdc1ac5de6a93f5de93203ed5.tar.xz | |
mm: madvise: use per_vma lock for MADV_FREE
MADV_FREE is another option, besides MADV_DONTNEED, for dynamic memory
freeing in user-space native or Java heap memory management. For example,
jemalloc can be configured to use MADV_FREE, and recent versions of the
Android Java heap have also increasingly adopted MADV_FREE. Supporting
per-VMA locking for MADV_FREE thus appears increasingly necessary.
We have replaced walk_page_range() with walk_page_range_vma(). Along with
the proposed madvise_lock_mode by Lorenzo, the necessary infrastructure is
now in place to begin exploring per-VMA locking support for MADV_FREE and
potentially other madvise using walk_page_range_vma().
This patch adds support for the PGWALK_VMA_RDLOCK walk_lock mode in
walk_page_range_vma(), and leverages madvise_lock_mode from madv_behavior
to select the appropriate walk_lock—either mmap_lock or per-VMA
lock—based on the context.
Because we now dynamically update the walk_ops->walk_lock field, we must
ensure this is thread-safe. The madvise_free_walk_ops is now defined as a
stack variable instead of a global constant.
Link: https://lkml.kernel.org/r/20250611104745.57405-1-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: SeongJae Park <sj@kernel.org>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Tangquan Zheng <zhengtangquan@oppo.com>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/pagewalk.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/pagewalk.h b/include/linux/pagewalk.h index 8ac2f6d6d2a3..682472c15495 100644 --- a/include/linux/pagewalk.h +++ b/include/linux/pagewalk.h @@ -14,6 +14,8 @@ enum page_walk_lock { PGWALK_WRLOCK = 1, /* vma is expected to be already write-locked during the walk */ PGWALK_WRLOCK_VERIFY = 2, + /* vma is expected to be already read-locked during the walk */ + PGWALK_VMA_RDLOCK_VERIFY = 3, }; /** |