linux-toradex.git/mm/zswap.c, branch v5.17

frontswap: remove support for multiple ops

2022-01-22T06:33:38+00:00

There is only a single instance of frontswap ops in the kernel, so
simplify the frontswap code by removing support for multiple operations.

Link: https://lkml.kernel.org/r/20211224062246.1258487-13-hch@lst.de
Signed-off-by: Christoph Hellwig 
Reviewed-by: Juergen Gross 
Cc: Dan Streetman 
Cc: Geert Uytterhoeven 
Cc: Hugh Dickins 
Cc: Konrad Rzeszutek Wilk 
Cc: Matthew Wilcox (Oracle) 
Cc: Seth Jennings 
Cc: Vitaly Wool 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/zswap.c: fix two bugs in zswap_writeback_entry()

2021-07-01T03:47:31+00:00

In the ZSWAP_SWAPCACHE_FAIL and ZSWAP_SWAPCACHE_EXIST case, we forgot to
call zpool_unmap_handle() when zpool can't sleep. And we might sleep in
zswap_get_swap_cache_page() while zpool can't sleep. To fix all of these,
zpool_unmap_handle() should be done before zswap_get_swap_cache_page()
when zpool can't sleep.

Link: https://lkml.kernel.org/r/20210522092242.3233191-4-linmiaohe@huawei.com
Fixes: fc6697a89f56 ("mm/zswap: add the flag can_sleep_mapped")
Signed-off-by: Miaohe Lin 
Cc: Colin Ian King 
Cc: Dan Streetman 
Cc: Nathan Chancellor 
Cc: Sebastian Andrzej Siewior 
Cc: Seth Jennings 
Cc: Tian Tao 
Cc: Vitaly Wool 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/zswap.c: avoid unnecessary copy-in at map time

2021-07-01T03:47:31+00:00

The buf mapped via zpool_map_handle() is only used to store compressed
page buffer and there is no information to extract from it. So we could
use ZPOOL_MM_WO instead to avoid unnecessary copy-in at map time.

Link: https://lkml.kernel.org/r/20210522092242.3233191-3-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin 
Cc: Colin Ian King 
Cc: Dan Streetman 
Cc: Nathan Chancellor 
Cc: Sebastian Andrzej Siewior 
Cc: Seth Jennings 
Cc: Tian Tao 
Cc: Vitaly Wool 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/zswap.c: remove unused function zswap_debugfs_exit()

2021-07-01T03:47:31+00:00

Patch series "Cleanup and fixup for zswap".

This series contains cleanups to remove unused function and avoid
unnecessary copy-in at map time.  Also this fixes two bugs in the function
zswap_writeback_entry().  More details can be found in the respective
changelogs.

This patch (of 3):

zswap_debugfs_exit() is unused, remove it.

Link: https://lkml.kernel.org/r/20210522092242.3233191-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20210522092242.3233191-2-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin 
Cc: Seth Jennings 
Cc: Dan Streetman 
Cc: Vitaly Wool 
Cc: Sebastian Andrzej Siewior 
Cc: Nathan Chancellor 
Cc: Colin Ian King 
Cc: Tian Tao 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/zswap.c: switch from strlcpy to strscpy

2021-05-05T18:27:27+00:00

strlcpy is marked as deprecated in Documentation/process/deprecated.rst,
and there is no functional difference when the caller expects truncation
(when not checking the return value).  strscpy is relatively better as
it also avoids scanning the whole source string.

Link: https://lkml.kernel.org/r/1614227981-20367-1-git-send-email-daizhiyuan@phytium.com.cn
Signed-off-by: Zhiyuan Dai 
Cc: Seth Jennings 
Cc: Dan Streetman 
Cc: Vitaly Wool 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/zswap: add the flag can_sleep_mapped

2021-02-26T17:41:01+00:00

Patch series "Fix the compatibility of zsmalloc and zswap".

Patch #1 adds a flag to zpool, then zswap used to determine if zpool
drivers such as zbud/z3fold/zsmalloc will enter an atomic context after
mapping.

The difference between zbud/z3fold and zsmalloc is that zsmalloc requires
an atomic context that since its map function holds a preempt-disabled,
but zbud/z3fold don't require an atomic context.  So patch #2 sets flag
sleep_mapped to true indicating that zbud/z3fold can sleep after mapping.
zsmalloc didn't support sleep after mapping, so don't set that flag to
true.

This patch (of 2):

Add a flag to zpool, named is "can_sleep_mapped", and have it set true for
zbud/z3fold, not set this flag for zsmalloc, so its default value is
false.  Then zswap could go the current path if the flag is true; and if
it's false, copy data from src to a temporary buffer, then unmap the
handle, take the mutex, process the buffer instead of src to avoid
sleeping function called from atomic context.

[natechancellor@gmail.com: add return value in zswap_frontswap_load]
  Link: https://lkml.kernel.org/r/20210121214804.926843-1-natechancellor@gmail.com
[tiantao6@hisilicon.com: fix potential memory leak]
  Link: https://lkml.kernel.org/r/1611538365-51811-1-git-send-email-tiantao6@hisilicon.com
[colin.king@canonical.com: fix potential uninitialized pointer read on tmp]
  Link: https://lkml.kernel.org/r/20210128141728.639030-1-colin.king@canonical.com
[tiantao6@hisilicon.com: fix variable 'entry' is uninitialized when used]
  Link: https://lkml.kernel.org/r/1611223030-58346-1-git-send-email-tiantao6@hisilicon.comLink: https://lkml.kernel.org/r/1611035683-12732-1-git-send-email-tiantao6@hisilicon.com

Link: https://lkml.kernel.org/r/1611035683-12732-2-git-send-email-tiantao6@hisilicon.com
Signed-off-by: Tian Tao 
Signed-off-by: Nathan Chancellor 
Signed-off-by: Colin Ian King 
Reviewed-by: Vitaly Wool 
Acked-by: Sebastian Andrzej Siewior 
Reported-by: Mike Galbraith 
Cc: Barry Song 
Cc: Dan Streetman 
Cc: Seth Jennings 
Cc: Dan Carpenter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: zswap: clean up confusing comment

2021-02-26T17:41:01+00:00

Correct wording and change one duplicated word (it) to "it is".

Link: https://lkml.kernel.org/r/20201221042848.13980-1-rdunlap@infradead.org
Fixes: 0ab0abcf5115 ("mm/zswap: refactor the get/put routines")
Signed-off-by: Randy Dunlap 
Cc: Weijie Yang 
Cc: Seth Jennings 
Cc: Seth Jennings 
Cc: Dan Streetman 
Cc: Vitaly Wool 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/zswap: move to use crypto_acomp API for hardware acceleration

2020-12-15T20:13:46+00:00

Right now, all new ZIP drivers are adapted to crypto_acomp APIs rather
than legacy crypto_comp APIs.  Tradiontal ZIP drivers like lz4,lzo etc
have been also wrapped into acomp via scomp backend.  But zswap.c is still
using the old APIs.  That means zswap won't be able to work on any new ZIP
drivers in kernel.

This patch moves to use cryto_acomp APIs to fix the disconnected bridge
between new ZIP drivers and zswap.  It is probably the first real user to
use acomp but perhaps not a good example to demonstrate how multiple acomp
requests can be executed in parallel in one acomp instance.  frontswap is
doing page load and store page by page synchronously.  swap_writepage()
depends on the completion of frontswap_store() to decide if it should call
__swap_writepage() to swap to disk.

However this patch creates multiple acomp instances, so multiple threads
running on multiple different cpus can actually do (de)compression
parallelly, leveraging the power of multiple ZIP hardware queues.  This is
also consistent with frontswap's page management model.

The old zswap code uses atomic context and avoids the race conditions
while shared resources like zswap_dstmem are accessed.  Here since acomp
can sleep, per-cpu mutex is used to replace preemption-disable.

While it is possible to make mm/page_io.c and mm/frontswap.c support async
(de)compression in some way, the entire design requires careful thinking
and performance evaluation.  For the first step, the base with fixed
connection between ZIP drivers and zswap should be built.

Link: https://lkml.kernel.org/r/20201107065332.26992-1-song.bao.hua@hisilicon.com
Signed-off-by: Barry Song 
Acked-by: Vitaly Wool 
Cc: Luis Claudio R. Goncalves 
Cc: Sebastian Andrzej Siewior 
Cc: Herbert Xu 
Cc: David S. Miller 
Cc: Mahipal Challa 
Cc: Seth Jennings 
Cc: Dan Streetman 
Cc: Zhou Wang 
Cc: Colin Ian King 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/zswap: fix passing zero to 'PTR_ERR' warning

2020-12-15T20:13:46+00:00

Fix smatch warning:

  mm/zswap.c:425 zswap_cpu_comp_prepare() warn: passing zero to 'PTR_ERR'

crypto_alloc_comp() never return NULL, use IS_ERR instead of
IS_ERR_OR_NULL to fix this.

Link: https://lkml.kernel.org/r/20201031055615.28080-1-yuehaibing@huawei.com
Fixes: f1c54846ee45 ("zswap: dynamic pool creation")
Signed-off-by: YueHaibing 
Reviewed-by: David Hildenbrand 
Cc: Seth Jennings 
Cc: Dan Streetman 
Cc: Vitaly Wool 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/zswap: make struct kernel_param_ops definitions const

2020-12-15T20:13:46+00:00

These should be const, so make it so.

Link: https://lkml.kernel.org/r/1791535ee0b00f4a5c68cc4a8adada06593ad8f1.1601770305.git.joe@perches.com
Signed-off-by: Joe Perches 
Cc: Seth Jennings 
Cc: Dan Streetman 
Cc: Vitaly Wool 
Cc: "Maciej S. Szmigiero" 
Cc: Dan Carpenter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds