mm: zpool: return pool size in pages

All zswap backends track their pool sizes in pages. Currently they
multiply by PAGE_SIZE for zswap, only for zswap to divide again in order
to do limit math. R

mm: zpool: return pool size in pages

All zswap backends track their pool sizes in pages. Currently they
multiply by PAGE_SIZE for zswap, only for zswap to divide again in order
to do limit math. Report pages directly.

Link: https://lkml.kernel.org/r/20240312153901.3441-2-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/z3fold: fix the comment for __encode_handle()

The comment is confusing that Pool lock should be held as this function
accesses first_num above the __encode_handle() because first_num is the
eleme

mm/z3fold: fix the comment for __encode_handle()

The comment is confusing that Pool lock should be held as this function
accesses first_num above the __encode_handle() because first_num is the
element of z3fold_header which is protected by z3fold_header->page_lock.

I found the same comment for encode_handle() in zbud.c by accident ,Pool
lock should be held as this function accesses first|last_chunks, which is
the element of zbud_header and it does not have any lock, so pool lock
should be held.

Z3fold is based on zbud, maybe the comment come from zbud, but it was
wrong, so fix it.

Link: https://lkml.kernel.org/r/20240219024453.2240147-1-hezhongkun.hzk@bytedance.com
Signed-off-by: Zhongkun He <hezhongkun.hzk@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/z3fold: remove obsolete comment for struct z3fold_pool

Since commit e774a7bc7f0a ("mm: zswap: remove page reclaim logic from
z3fold"), zpool and zpool_ops have been removed, so also remove the
co

mm/z3fold: remove obsolete comment for struct z3fold_pool

Since commit e774a7bc7f0a ("mm: zswap: remove page reclaim logic from
z3fold"), zpool and zpool_ops have been removed, so also remove the
corresponding comments.

Link: https://lkml.kernel.org/r/20230814221142.486548-1-xiujianfeng@huaweicloud.com
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/z3fold: use helper function put_z3fold_locked() and put_z3fold_locked_list()

This code is already duplicated six times, use helper function
put_z3fold_locked() to release z3fold page instead of o

mm/z3fold: use helper function put_z3fold_locked() and put_z3fold_locked_list()

This code is already duplicated six times, use helper function
put_z3fold_locked() to release z3fold page instead of open code it to help
improve code readability a bit. And add put_z3fold_locked_list() helper
function to be consistent with it. No functional change involved.

Link: https://lkml.kernel.org/r/20230803113824.886413-1-ruanjinjie@huawei.com
Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm: zswap: remove shrink from zpool interface

Now that all three zswap backends have removed their shrink code, it is
no longer necessary for the zpool interface to include shrink/writeback
endpoint

mm: zswap: remove shrink from zpool interface

Now that all three zswap backends have removed their shrink code, it is
no longer necessary for the zpool interface to include shrink/writeback
endpoints.

Link: https://lkml.kernel.org/r/20230612093815.133504-6-cerasuolodomenico@gmail.com
Signed-off-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm: zswap: remove page reclaim logic from z3fold

Switch z3fold to the new generic zswap LRU and remove its custom
implementation.

Link: https://lkml.kernel.org/r/20230612093815.133504-4-cerasuolodo

mm: zswap: remove page reclaim logic from z3fold

Switch z3fold to the new generic zswap LRU and remove its custom
implementation.

Link: https://lkml.kernel.org/r/20230612093815.133504-4-cerasuolodomenico@gmail.com
Signed-off-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

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mm: remove PageMovable export

The only in-kernel users that need PageMovable() to be exported are z3fold
and zsmalloc and they are only using it for dubious debugging
functionality. So remove those

mm: remove PageMovable export

The only in-kernel users that need PageMovable() to be exported are z3fold
and zsmalloc and they are only using it for dubious debugging
functionality. So remove those usages and the export so that no driver
code accidentally thinks that they are allowed to use this symbol.

Link: https://lkml.kernel.org/r/20230106135900.3763622-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

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zpool: clean out dead code

There is a lot of provision for flexibility that isn't actually needed or
used. Zswap (the only zpool user) always passes zpool_ops with an .evict
method set. The backen

zpool: clean out dead code

There is a lot of provision for flexibility that isn't actually needed or
used. Zswap (the only zpool user) always passes zpool_ops with an .evict
method set. The backends who reclaim only do so for zswap, so they can
also directly call zpool_ops without indirection or checks.

Finally, there is no need to check the retries parameters and bail with
-EINVAL in the reclaim function, when that's called just a few lines below
with a hard-coded 8. There is no need to duplicate the evictable and
sleep_mapped attrs from the driver in zpool_ops.

Link: https://lkml.kernel.org/r/20221128191616.1261026-3-nphamcs@gmail.com
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

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mm: Convert all PageMovable users to movable_operations

These drivers are rather uncomfortably hammered into the
address_space_operations hole. They aren't filesystems and don't behave
like filesys

mm: Convert all PageMovable users to movable_operations

These drivers are rather uncomfortably hammered into the
address_space_operations hole. They aren't filesystems and don't behave
like filesystems. They just need their own movable_operations structure,
which we can point to directly from page->mapping.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

show more ...

mm/z3fold: fix z3fold_page_migrate races with z3fold_map

Think about the below scenario:

CPU1 CPU2
z3fold_page_migrate z3fold_map
z3fold_page_trylock
...
z3fold_page_unlock
/* slots st

mm/z3fold: fix z3fold_page_migrate races with z3fold_map

Think about the below scenario:

CPU1 CPU2
z3fold_page_migrate z3fold_map
z3fold_page_trylock
...
z3fold_page_unlock
/* slots still points to old zhdr*/
get_z3fold_header
get slots from handle
get old zhdr from slots
z3fold_page_trylock
return *old* zhdr
encode_handle(new_zhdr, FIRST|LAST|MIDDLE)
put_page(page) /* zhdr is freed! */
but zhdr is still used by caller!

z3fold_map can map freed z3fold page and lead to use-after-free bug. To
fix it, we add PAGE_MIGRATED to indicate z3fold page is migrated and soon
to be released. So get_z3fold_header won't return such page.

Link: https://lkml.kernel.org/r/20220429064051.61552-10-linmiaohe@huawei.com
Fixes: 1f862989b04a ("mm/z3fold.c: support page migration")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/z3fold: fix z3fold_reclaim_page races with z3fold_free

Think about the below scenario:

CPU1 CPU2
z3fold_reclaim_page z3fold_free
spin_lock(&pool->lock) get_z3fold_header -- hold page_lock

mm/z3fold: fix z3fold_reclaim_page races with z3fold_free

Think about the below scenario:

CPU1 CPU2
z3fold_reclaim_page z3fold_free
spin_lock(&pool->lock) get_z3fold_header -- hold page_lock
kref_get_unless_zero
kref_put--zhdr->refcount can be 1 now
!z3fold_page_trylock
kref_put -- zhdr->refcount is 0 now
release_z3fold_page
WARN_ON(!list_empty(&zhdr->buddy)); -- we're on buddy now!
spin_lock(&pool->lock); -- deadlock here!

z3fold_reclaim_page might race with z3fold_free and will lead to pool lock
deadlock and zhdr buddy non-empty warning. To fix this, defer getting the
refcount until page_lock is held just like what __z3fold_alloc does. Note
this has the side effect that we won't break the reclaim if we meet a soon
to be released z3fold page now.

Link: https://lkml.kernel.org/r/20220429064051.61552-9-linmiaohe@huawei.com
Fixes: dcf5aedb24f8 ("z3fold: stricter locking and more careful reclaim")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/z3fold: always clear PAGE_CLAIMED under z3fold page lock

Think about the below race window:

CPU1 CPU2
z3fold_reclaim_page z3fold_free
test_and_set_bit PAGE_CLAIMED
failed to reclaim page

mm/z3fold: always clear PAGE_CLAIMED under z3fold page lock

Think about the below race window:

CPU1 CPU2
z3fold_reclaim_page z3fold_free
test_and_set_bit PAGE_CLAIMED
failed to reclaim page
z3fold_page_lock(zhdr);
add back to the lru list;
z3fold_page_unlock(zhdr);
get_z3fold_header
page_claimed=test_and_set_bit PAGE_CLAIMED

clear_bit(PAGE_CLAIMED, &page->private);

if (!page_claimed) /* it's false true */
free_handle is not called

free_handle won't be called in this case. So z3fold_buddy_slots will leak.
Fix it by always clear PAGE_CLAIMED under z3fold page lock.

Link: https://lkml.kernel.org/r/20220429064051.61552-8-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/z3fold: put z3fold page back into unbuddied list when reclaim or migration fails

When doing z3fold page reclaim or migration, the page is removed from
unbuddied list. If reclaim or migration suc

mm/z3fold: put z3fold page back into unbuddied list when reclaim or migration fails

When doing z3fold page reclaim or migration, the page is removed from
unbuddied list. If reclaim or migration succeeds, it's fine as page is
released. But in case it fails, the page is not put back into unbuddied
list now. The page will be leaked until next compaction work, reclaim or
migration is done.

Link: https://lkml.kernel.org/r/20220429064051.61552-7-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

revert "mm/z3fold.c: allow __GFP_HIGHMEM in z3fold_alloc"

Revert commit f1549cb5ab2b ("mm/z3fold.c: allow __GFP_HIGHMEM in
z3fold_alloc").

z3fold can't support GFP_HIGHMEM page now. page_address i

revert "mm/z3fold.c: allow __GFP_HIGHMEM in z3fold_alloc"

Revert commit f1549cb5ab2b ("mm/z3fold.c: allow __GFP_HIGHMEM in
z3fold_alloc").

z3fold can't support GFP_HIGHMEM page now. page_address is used directly
at all places. Moreover, z3fold_header is on per cpu unbuddied list which
could be accessed anytime. So we should remove the support of GFP_HIGHMEM
allocation for z3fold.

Link: https://lkml.kernel.org/r/20220429064051.61552-6-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/z3fold: throw warning on failure of trylock_page in z3fold_alloc

If trylock_page fails, the page won't be non-lru movable page. When this
page is freed via free_z3fold_page, it will trigger bug

mm/z3fold: throw warning on failure of trylock_page in z3fold_alloc

If trylock_page fails, the page won't be non-lru movable page. When this
page is freed via free_z3fold_page, it will trigger bug on PageMovable
check in __ClearPageMovable. Throw warning on failure of trylock_page to
guard against such rare case just as what zsmalloc does.

Link: https://lkml.kernel.org/r/20220429064051.61552-5-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/z3fold: remove buggy use of stale list for allocation

Currently if z3fold couldn't find an unbuddied page it would first try to
pull a page off the stale list. But this approach is problematic.

mm/z3fold: remove buggy use of stale list for allocation

Currently if z3fold couldn't find an unbuddied page it would first try to
pull a page off the stale list. But this approach is problematic. If
init z3fold page fails later, the page should be freed via
free_z3fold_page to clean up the relevant resource instead of using
__free_page directly. And if page is successfully reused, it will BUG_ON
later in __SetPageMovable because it's already non-lru movable page, i.e.
PAGE_MAPPING_MOVABLE is already set in page->mapping. In order to fix all
of these issues, we can simply remove the buggy use of stale list for
allocation because can_sleep should always be false and we never really
hit the reusing code path now.

Link: https://lkml.kernel.org/r/20220429064051.61552-4-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/z3fold: fix possible null pointer dereferencing

alloc_slots could fail to allocate memory under heavy memory pressure. So
we should check zhdr->slots against NULL to avoid future null pointer
de

mm/z3fold: fix possible null pointer dereferencing

alloc_slots could fail to allocate memory under heavy memory pressure. So
we should check zhdr->slots against NULL to avoid future null pointer
dereferencing.

Link: https://lkml.kernel.org/r/20220429064051.61552-3-linmiaohe@huawei.com
Fixes: fc5488651c7d ("z3fold: simplify freeing slots")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/z3fold: fix sheduling while atomic

Patch series "A few fixup patches for z3fold".

This series contains a few fixup patches to fix sheduling while atomic,
fix possible null pointer dereferencing,

mm/z3fold: fix sheduling while atomic

Patch series "A few fixup patches for z3fold".

This series contains a few fixup patches to fix sheduling while atomic,
fix possible null pointer dereferencing, fix various race conditions and
so on. More details can be found in the respective changelogs.


This patch (of 9):

z3fold's page_lock is always held when calling alloc_slots. So gfp should
be GFP_ATOMIC to avoid "scheduling while atomic" bug.

Link: https://lkml.kernel.org/r/20220429064051.61552-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20220429064051.61552-2-linmiaohe@huawei.com
Fixes: fc5488651c7d ("z3fold: simplify freeing slots")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/z3fold: remove unneeded PAGE_HEADLESS check in free_handle()

The only caller z3fold_free() never calls free_handle() in PAGE_HEADLESS
case. Remove this unneeded check.

Link: https://lkml.kernel

mm/z3fold: remove unneeded PAGE_HEADLESS check in free_handle()

The only caller z3fold_free() never calls free_handle() in PAGE_HEADLESS
case. Remove this unneeded check.

Link: https://lkml.kernel.org/r/20220308134311.59086-9-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/z3fold: remove redundant list_del_init of zhdr->buddy in z3fold_free

do_compact_page() will do list_del_init(&zhdr->buddy) for us. Remove this
extra one to save some possible cpu cycles.

Link:

mm/z3fold: remove redundant list_del_init of zhdr->buddy in z3fold_free

do_compact_page() will do list_del_init(&zhdr->buddy) for us. Remove this
extra one to save some possible cpu cycles.

Link: https://lkml.kernel.org/r/20220308134311.59086-8-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/z3fold: move decrement of pool->pages_nr into __release_z3fold_page()

The z3fold will always do atomic64_dec(&pool->pages_nr) when the
__release_z3fold_page() is called. Thus we can move decreme

mm/z3fold: move decrement of pool->pages_nr into __release_z3fold_page()

The z3fold will always do atomic64_dec(&pool->pages_nr) when the
__release_z3fold_page() is called. Thus we can move decrement of
pool->pages_nr into __release_z3fold_page() to simplify the code.

Also we can reduce the size of z3fold.o ~1k.

Without this patch:
text data bss dec hex filename
15444 1376 8 16828 41bc mm/z3fold.o
With this patch:
text data bss dec hex filename
15044 1248 8 16300 3fac mm/z3fold.o

Link: https://lkml.kernel.org/r/20220308134311.59086-7-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/z3fold: remove confusing local variable l reassignment

The local variable l holds the address of unbuddied[i] which won't change
after we take the pool lock. Remove it to avoid confusion.

Link:

mm/z3fold: remove confusing local variable l reassignment

The local variable l holds the address of unbuddied[i] which won't change
after we take the pool lock. Remove it to avoid confusion.

Link: https://lkml.kernel.org/r/20220308134311.59086-6-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/z3fold: remove unneeded page_mapcount_reset and ClearPagePrivate

Page->page_type and PagePrivate are not used in z3fold. We should remove
these confusing unneeded operations. The z3fold do thes

mm/z3fold: remove unneeded page_mapcount_reset and ClearPagePrivate

Page->page_type and PagePrivate are not used in z3fold. We should remove
these confusing unneeded operations. The z3fold do these here is due to
referring to zsmalloc's migration code which does need these operations.

Link: https://lkml.kernel.org/r/20220308134311.59086-5-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/z3fold: minor clean up for z3fold_free

Use put_z3fold_header() to pair with get_z3fold_header. Also fix the
wrong comments. Minor readability improvement.

Link: https://lkml.kernel.org/r/20220

mm/z3fold: minor clean up for z3fold_free

Use put_z3fold_header() to pair with get_z3fold_header. Also fix the
wrong comments. Minor readability improvement.

Link: https://lkml.kernel.org/r/20220308134311.59086-4-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/z3fold: remove obsolete comment in z3fold_alloc

The highmem pages are supported since commit f1549cb5ab2b ("mm/z3fold.c:
allow __GFP_HIGHMEM in z3fold_alloc"). Remove the residual comment.

Link

mm/z3fold: remove obsolete comment in z3fold_alloc

The highmem pages are supported since commit f1549cb5ab2b ("mm/z3fold.c:
allow __GFP_HIGHMEM in z3fold_alloc"). Remove the residual comment.

Link: https://lkml.kernel.org/r/20220308134311.59086-3-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...