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authorLuis Chamberlain <mcgrof@kernel.org>2023-03-09 15:05:45 -0800
committerAndrew Morton <akpm@linux-foundation.org>2023-03-28 16:20:15 -0700
commit2c6efe9cf2d7841b75fe38ed1adbd41a90f51ba0 (patch)
tree6b649bab7e8913980c89b34292998920be7f78c5 /Documentation/mm
parentd0f5a85442d1a0552eae681b2e8cdc86ac08aba2 (diff)
shmem: add support to ignore swap
In doing experimentations with shmem having the option to avoid swap becomes a useful mechanism. One of the *raves* about brd over shmem is you can avoid swap, but that's not really a good reason to use brd if we can instead use shmem. Using brd has its own good reasons to exist, but just because "tmpfs" doesn't let you do that is not a great reason to avoid it if we can easily add support for it. I don't add support for reconfiguring incompatible options, but if we really wanted to we can add support for that. To avoid swap we use mapping_set_unevictable() upon inode creation, and put a WARN_ON_ONCE() stop-gap on writepages() for reclaim. Link: https://lkml.kernel.org/r/20230309230545.2930737-7-mcgrof@kernel.org Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Acked-by: Christian Brauner <brauner@kernel.org> Tested-by: Xin Hao <xhao@linux.alibaba.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Cc: Adam Manzanares <a.manzanares@samsung.com> Cc: David Hildenbrand <david@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hugh Dickins <hughd@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Pankaj Raghav <p.raghav@samsung.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'Documentation/mm')
-rw-r--r--Documentation/mm/unevictable-lru.rst2
1 files changed, 2 insertions, 0 deletions
diff --git a/Documentation/mm/unevictable-lru.rst b/Documentation/mm/unevictable-lru.rst
index 92ac5dca420c..d5ac8511eb67 100644
--- a/Documentation/mm/unevictable-lru.rst
+++ b/Documentation/mm/unevictable-lru.rst
@@ -42,6 +42,8 @@ The unevictable list addresses the following classes of unevictable pages:
* Those owned by ramfs.
+ * Those owned by tmpfs with the noswap mount option.
+
* Those mapped into SHM_LOCK'd shared memory regions.
* Those mapped into VM_LOCKED [mlock()ed] VMAs.