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Update DAMON debugfs interface sections on the usage document to reflect
the fact that 'monitor_on' file has renamed to 'monitor_on_DEPRECATED'.
Link: https://lkml.kernel.org/r/20240130013549.89538-9-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Kernel builders could silently enable CONFIG_DAMON_DBGFS_DEPRECATED.
Users who manually check the files under the DAMON debugfs directory could
notice the deprecation owing to the 'DEPRECATED' DAMON debugfs file, but
there could be users who doesn't manually check the files.
Make the deprecation cannot be ignored in the case by renaming
'monitor_on' file, which is essential for real use of DAMON on runtime, to
'monitor_on_DEPRECATED'. Still users who control DAMON via only
user-space tool could ignore the deprecation, but that's what the tool
developers should take care of. DAMON user-space tool, damo, has also
made a change[1] for the purpose.
[1] commit 935dae76f2aee ("_damon_args: Rename --damon_interface to
--damon_interface_DEPRECATED") of https://github.com/awslabs/damo
Link: https://lkml.kernel.org/r/20240130013549.89538-8-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Following change will rename 'monitor_on' DAMON debugfs file to
'monitor_on_DEPRECATED', to make the deprecation unignorable in runtime.
Since it could make DAMON selftests fail and disturb future bisects,
update DAMON selftests to support the change.
Link: https://lkml.kernel.org/r/20240130013549.89538-7-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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interface
Document the newly added DAMON debugfs interface deprecation notice file
on the usage document.
Link: https://lkml.kernel.org/r/20240130013549.89538-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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DAMON debugfs interface deprecation message is written twice, once for the
warning, and again for DEPRECATED file's read output. De-duplicate those
by defining the message as a macro and reuse.
[akpm@linux-foundation.org: s/comnst/const/]
Link: https://lkml.kernel.org/r/20240130013549.89538-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Implement a read-only file for DAMON debugfs interface deprecation notice,
to let users who manually read/write the DAMON debugfs files from their
shell command line easily notice the fact.
[arnd@arndb.de: fix bogus string length]
Link: https://lkml.kernel.org/r/20240202124339.892862-1-arnd@kernel.org
Link: https://lkml.kernel.org/r/20240130013549.89538-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Alex Shi <alexs@kernel.org>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yanteng Si <siyanteng@loongson.cn>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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DAMON debugfs interface is deprecated. The fact has documented by commit
5445fcbc4cda ("Docs/admin-guide/mm/damon/usage: add DAMON debugfs
interface deprecation notice"). Commit 620932cd2852 ("mm/damon/dbgfs:
print DAMON debugfs interface deprecation message") further started
printing a warning message when users still use it. Many people don't
read documentation or kernel log, though.
Make the deprecation harder to be ignored using the approach of commit
eb07c4f39c3e ("mm/slab: rename CONFIG_SLAB to CONFIG_SLAB_DEPRECATED").
'make oldconfig' with 'CONFIG_DAMON_DBGFS=y' will get a new prompt with
the explicit deprecation notice on the name. 'make olddefconfig' with
'CONFIG_DAMON_DBGFS=y' will result in not building DAMON debugfs
interface. If there is a real user of DAMON debugfs interface, they will
complain the change to the builder.
Link: https://lkml.kernel.org/r/20240130013549.89538-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "mm/damon: make DAMON debugfs interface deprecation
unignorable".
DAMON debugfs interface is deprecated in February 2023, by commit
5445fcbc4cda ("Docs/admin-guide/mm/damon/usage: add DAMON debugfs
interface deprecation notice"). Make the fact unable to be easily ignored
by removing an example usage from the document (patch 1), renaming the
config (patch 2), adding a deprecation notice file to the debugfs
directory (patches 3-5), and renaming the debugfs file that essnetial to
be used for real use of DAMON (patches 6-9).
This patch (of 9):
DAMON tracepoints example on the DAMON usage document is using DAMON
debugfs interface, which is deprecated. Use its alternative, DAMON sysfs
interface.
Link: https://lkml.kernel.org/r/20240130013549.89538-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20240130013549.89538-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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shrink_memcg_cb() is called by the shrinker and is based on
zswap_writeback_entry(). Move it in between. Save one fwd decl.
Link: https://lkml.kernel.org/r/20240130014208.565554-21-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Shrinking needs writeback. Naturally, move the writeback code above
the shrinking code. Delete the forward decl.
Link: https://lkml.kernel.org/r/20240130014208.565554-20-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The per-cpu compression init/exit callbacks are awkwardly in the
middle of the shrinker code. Move them up to the compression section.
Link: https://lkml.kernel.org/r/20240130014208.565554-19-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Writeback needs to decompress. Move the (de)compression API above what
will be the consolidated shrinking/writeback code.
Link: https://lkml.kernel.org/r/20240130014208.565554-18-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The higher-level entry operations modify the tree, so move the entry
API after the tree section.
Link: https://lkml.kernel.org/r/20240130014208.565554-17-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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This completes consolidation of the LRU section.
Link: https://lkml.kernel.org/r/20240130014208.565554-16-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The zswap entry section sits awkwardly in the middle of LRU-related
functions. Group the external LRU API functions first.
Link: https://lkml.kernel.org/r/20240130014208.565554-15-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "mm: zswap: cleanups".
Cleanups and maintenance items that accumulated while reviewing zswap
patches.
This patch (of 20):
The parameters primarily control pool attributes. Move those
operations up to the pool section.
Link: https://lkml.kernel.org/r/20240130014208.565554-1-hannes@cmpxchg.org
Link: https://lkml.kernel.org/r/20240130014208.565554-14-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Move the operations against the global zswap_pools list (current pool,
last, find) to the pool section.
Link: https://lkml.kernel.org/r/20240130014208.565554-13-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Move pool refcounting functions into the pool section. First the
destroy functions, then the get and put which uses them.
__zswap_pool_empty() has an upward reference to the global
zswap_pools, to sanity check it's not the currently active pool that's
being freed. That gets the forward decl for zswap_pool_current().
This puts the get and put function above all callers, so kill the
forward decls as well.
Link: https://lkml.kernel.org/r/20240130014208.565554-12-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The function ordering in zswap.c is a little chaotic, which requires
jumping in unexpected directions when following related code. This is
a series of patches that brings the file into the following order:
- pool functions
- lru functions
- rbtree functions
- zswap entry functions
- compression/backend functions
- writeback & shrinking functions
- store, load, invalidate, swapon, swapoff
- debugfs
- init
But it has to be split up such the moving still produces halfway
readable diffs.
In this patch, move pool allocation and freeing functions.
Link: https://lkml.kernel.org/r/20240130014208.565554-11-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The branching is awkward and duplicates code. The comment about
writeback is also misleading: yes, the entry might have been written
back. Or it might have never been stored in zswap to begin with due to
a rejection - zswap_invalidate() is called on all exiting swap entries.
Link: https://lkml.kernel.org/r/20240130014208.565554-10-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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- Remove dupentry, reusing entry works just fine.
- Rename pool to shrink_pool, as this one actually is confusing.
- Remove page, use folio_nid() and kmap_local_folio() directly.
- Set entry->swpentry in a common path.
- Move value and src to local scope of use.
Link: https://lkml.kernel.org/r/20240130014208.565554-9-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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zswap_store() is long and mixes work at the zswap layer with work at
the backend and compression layer. Move compression & backend work to
zswap_compress(), mirroring zswap_decompress().
Link: https://lkml.kernel.org/r/20240130014208.565554-8-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Link: https://lkml.kernel.org/r/20240130014208.565554-7-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Remove stale comment and unnecessary local variable.
Link: https://lkml.kernel.org/r/20240130014208.565554-6-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Put a standard sanity check on zswap_entry_get() for UAF scenario.
Link: https://lkml.kernel.org/r/20240130014208.565554-5-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Move it up to the other tree and refcounting functions.
Link: https://lkml.kernel.org/r/20240130014208.565554-4-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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There is only one caller and the function is trivial. Inline it.
Link: https://lkml.kernel.org/r/20240130014208.565554-3-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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There is a zswap_entry_ namespace with multiple functions already.
Link: https://lkml.kernel.org/r/20240130014208.565554-2-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Since the only user zswap_lru_putback() has gone, remove
list_lru_putback() too.
Link: https://lkml.kernel.org/r/20240126-zswap-writeback-race-v2-3-b10479847099@bytedance.com
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Cc: Chris Li <chriscli@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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LRU writeback has race problem with swapoff, as spotted by Yosry [1]:
CPU1 CPU2
shrink_memcg_cb swap_off
list_lru_isolate zswap_invalidate
zswap_swapoff
kfree(tree)
// UAF
spin_lock(&tree->lock)
The problem is that the entry in lru list can't protect the tree from
being swapoff and freed, and the entry also can be invalidated and freed
concurrently after we unlock the lru lock.
We can fix it by moving the swap cache allocation ahead before referencing
the tree, then check invalidate race with tree lock, only after that we
can safely deref the entry. Note we couldn't deref entry or tree anymore
after we unlock the folio, since we depend on this to hold on swapoff.
So this patch moves all tree and entry usage to zswap_writeback_entry(),
we only use the copied swpentry on the stack to allocate swap cache and if
returned with folio locked we can reference the tree safely. Then we can
check invalidate race with tree lock, the following things is much the
same like zswap_load().
Since we can't deref the entry after zswap_writeback_entry(), we can't use
zswap_lru_putback() anymore, instead we rotate the entry in the beginning.
And it will be unlinked and freed when invalidated if writeback success.
Another change is we don't update the memcg nr_zswap_protected in the
-ENOMEM and -EEXIST cases anymore. -EEXIST case means we raced with
swapin or concurrent shrinker action, since swapin already have memcg
nr_zswap_protected updated, don't need double counts here. For concurrent
shrinker, the folio will be writeback and freed anyway. -ENOMEM case is
extremely rare and doesn't happen spuriously either, so don't bother
distinguishing this case.
[1] https://lore.kernel.org/all/CAJD7tkasHsRnT_75-TXsEe58V9_OW6m3g6CF7Kmsvz8CKRG_EA@mail.gmail.com/
Link: https://lkml.kernel.org/r/20240126-zswap-writeback-race-v2-2-b10479847099@bytedance.com
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Cc: Chris Li <chriscli@google.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In the x86 implementation of switch_mm_irqs_off(), we do not use the
"prev" argument passed in by the caller, we use exclusively use
"real_prev", which is cpu_tlbstate.loaded_mm. This is not obvious at the
first sight.
Furthermore, a comment describes a condition that happens when called with
prev == next, but this should not affect the function in any way since
prev is unused. Apparently, the comment is intended to clarify why we
don't rely on prev == next to decide whether we need to update CR3, but
again, it is not obvious. The comment also references the fact that
leave_mm() calls with prev == NULL and tsk == NULL, but this also
shouldn't matter because prev is unused and tsk is only used in one
function which has a NULL check.
Clarify things by renaming (prev -> unused) and (real_prev -> prev), also
move and rewrite the comment as an explanation for why we don't rely on
"prev" supplied by the caller in x86 code and use our own. Hopefully this
makes reading the code easier.
Link: https://lkml.kernel.org/r/20240126080644.1714297-2-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The argument is unused since commit 3d28ebceaffa ("x86/mm: Rework lazy
TLB to track the actual loaded mm"), delete it.
Link: https://lkml.kernel.org/r/20240126080644.1714297-1-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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For each CPU hotplug event, we will update per-CPU data slice size and
corresponding PCP configuration for every online CPU to make the
implementation simple. But, Kyle reported that this takes tens seconds
during boot on a machine with 34 zones and 3840 CPUs.
So, in this patch, for each CPU hotplug event, we only update per-CPU data
slice size and corresponding PCP configuration for the CPUs that share
caches with the hotplugged CPU. With the patch, the system boot time
reduces 67 seconds on the machine.
Link: https://lkml.kernel.org/r/20240126081944.414520-1-ying.huang@intel.com
Fixes: 362d37a106dd ("mm, pcp: reduce lock contention for draining high-order pages")
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Originally-by: Kyle Meyer <kyle.meyer@hpe.com>
Reported-and-tested-by: Kyle Meyer <kyle.meyer@hpe.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Instead of using try_to_freeze, use kthread_freezable_should_stop in
kswapd. By this, we can avoid unnecessary freezing when kswapd should
stop.
Link: https://lkml.kernel.org/r/20240126152556.58791-1-ppbuk5246@gmail.com
Signed-off-by: Levi Yun <ppbuk5246@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The root memcg is onlined even when memcg is disabled. When it's onlined
a 2 second periodic stat flush is started, but no stat flushing is
required when memcg is disabled because there can be no child memcgs.
Most calls to flush memcg stats are avoided when memcg is disabled as a
result of the mem_cgroup_disabled check added in 7d7ef0a4686a ("mm: memcg:
restore subtree stats flushing"), but the periodic flushing started in
mem_cgroup_css_online is not. Skip it.
Link: https://lkml.kernel.org/r/20240126211927.1171338-1-tjmercier@google.com
Fixes: aa48e47e3906 ("memcg: infrastructure to flush memcg stats")
Signed-off-by: T.J. Mercier <tjmercier@google.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Chris Li <chrisl@kernel.org>
Reported-by: Minchan Kim <minchan@google.com>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Michal Koutn <mkoutny@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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This test stresses the race between of madvise(DONTNEED), a page fault
and a parallel huge page mmap, which should fail due to lack of
available page available for mapping.
This test case must run on a system with one and only one huge page
available.
# echo 1 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
During setup, the test allocates the only available page, and starts
three threads:
- thread 1:
* madvise(MADV_DONTNEED) on the allocated huge page
- thread 2:
* Write to the allocated huge page
- thread 3:
* Tries to allocated (steal) an extra huge page (which is not
available)
thread 3 should never succeed in the allocation, since the only huge
page was never unmapped, and should be reserved.
Touching the old page after thread3 allocation will raise a SIGBUS.
Link: https://lkml.kernel.org/r/20240105155419.1939484-2-leitao@debian.org
Signed-off-by: Breno Leitao <leitao@debian.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Similarly to what's been done in commit 85716a80c16d ("kmsan: allow using
__msan_instrument_asm_store() inside runtime"), it should be safe to call
kmsan_unpoison_memory() from within the runtime, as it does not allocate
memory or take locks. Remove the redundant runtime checks.
This should fix false positives seen with CONFIG_DEBUG_LIST=y when
the non-instrumented lib/stackdepot.c failed to unpoison the memory
chunks later checked by the instrumented lib/list_debug.c
Also replace the implementation of kmsan_unpoison_entry_regs() with
a call to kmsan_unpoison_memory().
Link: https://lkml.kernel.org/r/20240124173134.1165747-1-glider@google.com
Fixes: f80be4571b19 ("kmsan: add KMSAN runtime core")
Signed-off-by: Alexander Potapenko <glider@google.com>
Tested-by: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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This was inadvertently skipped when adding the new functions.
Link: https://lkml.kernel.org/r/20240124181217.1761674-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Add a sysfs knob for dax devices to control the memmap_on_memory setting
if the dax device were to be hotplugged as system memory.
The default memmap_on_memory setting for dax devices originating via pmem
or hmem is set to 'false' - i.e. no memmap_on_memory semantics, to
preserve legacy behavior. For dax devices via CXL, the default is on.
The sysfs control allows the administrator to override the above defaults
if needed.
Link: https://lkml.kernel.org/r/20240124-vv-dax_abi-v7-5-20d16cb8d23d@intel.com
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Tested-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Huang, Ying <ying.huang@intel.com>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In preparation for adding sysfs ABI to toggle memmap_on_memory semantics
for drivers adding memory, export the mhp_supports_memmap_on_memory()
helper. This allows drivers to check if memmap_on_memory support is
available before trying to request it, and display an appropriate
message if it isn't available. As part of this, remove the size argument
to this - with recent updates to allow memmap_on_memory for larger
ranges, and the internal splitting of altmaps into respective memory
blocks, the size argument is meaningless.
[akpm@linux-foundation.org: fix build]
Link: https://lkml.kernel.org/r/20240124-vv-dax_abi-v7-4-20d16cb8d23d@intel.com
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Li Zhijian <lizhijian@fujitsu.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Add the missing sysfs ABI documentation for the device DAX subsystem.
Various ABI attributes under this have been present since v5.1, and more
have been added over time. In preparation for adding a new attribute,
add this file with the historical details.
Link: https://lkml.kernel.org/r/20240124-vv-dax_abi-v7-3-20d16cb8d23d@intel.com
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Li Zhijian <lizhijian@fujitsu.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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There were several places where drivers/dax/bus.c uses 'sprintf' to print
sysfs data. Since a sysfs_emit() helper is available specifically for
this purpose, replace all the sprintf() usage for sysfs with sysfs_emit()
in this file.
Link: https://lkml.kernel.org/r/20240124-vv-dax_abi-v7-2-20d16cb8d23d@intel.com
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Reported-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Li Zhijian <lizhijian@fujitsu.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "Add DAX ABI for memmap_on_memory", v7.
This series adds sysfs ABI to control memmap_on_memory behavior for DAX
devices.
Patch 1 replaces incorrect device_lock() usage with a local rwsem - this
was identified during review.
Patch 2 is also a preparatory patch that replaces sprintf() for sysfs
operations with sysfs_emit()
Patch 3 adds the missing documentation for the sysfs ABI for DAX regions
and Dax devices.
Patch 4 exports mhp_supports_memmap_on_memory().
Patch 5 adds the new ABI for toggling memmap_on_memory semantics for dax
devices.
This patch (of 5):
The dax driver incorrectly used driver-core device locks to protect
internal dax region and dax device configuration structures. Replace the
device lock usage with a local rwsem, one each for dax region
configuration and dax device configuration. As a result of this
conversion, no device_lock() usage remains in dax/bus.c.
Link: https://lkml.kernel.org/r/20240124-vv-dax_abi-v7-0-20d16cb8d23d@intel.com
Link: https://lkml.kernel.org/r/20240124-vv-dax_abi-v7-1-20d16cb8d23d@intel.com
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Reported-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Li Zhijian <lizhijian@fujitsu.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Commit 7310895779624 ("mm: zswap: tighten up entry invalidation") removed
the usage of tree argument, delete it.
Link: https://lkml.kernel.org/r/20240125081423.1200336-1-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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There is a lot of code needs to set the range of vma in mmap.c, introduce
vma_set_range() to simplify the code.
Link: https://lkml.kernel.org/r/20240124035719.3685193-1-yajun.deng@linux.dev
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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During swapoff, try_to_unuse() makes sure that zswap_invalidate() is
called for all swap entries before zswap_swapoff() is called. This means
that all zswap entries should already be removed from the tree. Simplify
zswap_swapoff() by removing the trees cleanup code, and leave an assertion
in its place.
Link: https://lkml.kernel.org/r/20240124045113.415378-3-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "mm: zswap: simplify zswap_swapoff()", v2.
These patches aim to simplify zswap_swapoff() by removing the unnecessary
trees cleanup code. Patch 1 makes sure that the order of operations
during swapoff is enforced correctly, making sure the simplification in
patch 2 is correct in a future-proof manner.
This patch (of 2):
In swap_range_free(), we update inuse_pages then do some cleanups (arch
invalidation, zswap invalidation, swap cache cleanups, etc). During
swapoff, try_to_unuse() checks that inuse_pages is 0 to make sure all swap
entries are freed. Make sure we only update inuse_pages after we are done
with the cleanups in swap_range_free(), and use the proper memory barriers
to enforce it. This makes sure that code following try_to_unuse() can
safely assume that swap_range_free() ran for all entries in thr swapfile
(e.g. swap cache cleanup, zswap_swapoff()).
In practice, this currently isn't a problem because swap_range_free() is
called with the swap info lock held, and the swapoff code happens to spin
for that after try_to_unuse(). However, this seems fragile and
unintentional, so make it more relable and future-proof. This also
facilitates a following simplification of zswap_swapoff().
Link: https://lkml.kernel.org/r/20240124045113.415378-1-yosryahmed@google.com
Link: https://lkml.kernel.org/r/20240124045113.415378-2-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Each swapfile has one rb-tree to search the mapping of swp_entry_t to
zswap_entry, that use a spinlock to protect, which can cause heavy lock
contention if multiple tasks zswap_store/load concurrently.
Optimize the scalability problem by splitting the zswap rb-tree into
multiple rb-trees, each corresponds to SWAP_ADDRESS_SPACE_PAGES (64M),
just like we did in the swap cache address_space splitting.
Although this method can't solve the spinlock contention completely, it
can mitigate much of that contention. Below is the results of kernel
build in tmpfs with zswap shrinker enabled:
linux-next zswap-lock-optimize
real 1m9.181s 1m3.820s
user 17m44.036s 17m40.100s
sys 7m37.297s 4m54.622s
So there are clearly improvements.
Link: https://lkml.kernel.org/r/20240117-b4-zswap-lock-optimize-v2-2-b5cc55479090@bytedance.com
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Cc: Chris Li <chriscli@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "mm/zswap: optimize the scalability of zswap rb-tree", v2.
When testing the zswap performance by using kernel build -j32 in a tmpfs
directory, I found the scalability of zswap rb-tree is not good, which is
protected by the only spinlock. That would cause heavy lock contention if
multiple tasks zswap_store/load concurrently.
So a simple solution is to split the only one zswap rb-tree into multiple
rb-trees, each corresponds to SWAP_ADDRESS_SPACE_PAGES (64M). This idea
is from the commit 4b3ef9daa4fc ("mm/swap: split swap cache into 64MB
trunks").
Although this method can't solve the spinlock contention completely, it
can mitigate much of that contention. Below is the results of kernel
build in tmpfs with zswap shrinker enabled:
linux-next zswap-lock-optimize
real 1m9.181s 1m3.820s
user 17m44.036s 17m40.100s
sys 7m37.297s 4m54.622s
So there are clearly improvements. And it's complementary with the
ongoing zswap xarray conversion by Chris. Anyway, I think we can also
merge this first, it's complementary IMHO. So I just refresh and resend
this for further discussion.
This patch (of 2):
Not all zswap interfaces can handle the absence of the zswap rb-tree,
actually only zswap_store() has handled it for now.
To make things simple, we make sure each swapfile always have the zswap
rb-tree prepared before being enabled and used. The preparation is
unlikely to fail in practice, this patch just make it explicit.
Link: https://lkml.kernel.org/r/20240117-b4-zswap-lock-optimize-v2-0-b5cc55479090@bytedance.com
Link: https://lkml.kernel.org/r/20240117-b4-zswap-lock-optimize-v2-1-b5cc55479090@bytedance.com
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Cc: Chris Li <chriscli@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Commit 2cafb582173f ("mempolicy: remove confusing MPOL_MF_LAZY dead code")
removes MPOL_MF_LAZY handling in queue_pages_test_walk(), and with that,
there is no effective use of the local variable endvma in that function
remaining.
Remove the local variable endvma and its dead code. No functional change.
This issue was identified with clang-analyzer's dead stores analysis.
Link: https://lkml.kernel.org/r/20240122092504.18377-1-lukas.bulwahn@gmail.com
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|