This patch series vectorizes and simplifies the existing
zswap_store()/zswap_store_page() implementation so that the IAA compress
batching functionality in [1] can be developed seamlessly with minimal
impact to zswap_store() code; while still having a single consolidated
implementation of zswap_store() for batching/non-batching compression
algorithms, which will make the code easier to maintain.
These changes have been developed based on code review comments in [2].
I would greatly appreciate suggestions for further improving the patches in
this series.
Once this patch series is reviewed, I intend to incorporate these patches
in the IAA compress batching series [1], to develop a v5 of that series.
The main focus of testing this specific series was to make sure there are no
performance regressions. usemem 30 processes was run for three folio
configurations, with zstd and with deflate-iaa:
1) 4k folios
2) 16k/32k/64k folios
3) 2M folios
System setup for testing:
=========================
Testing of this patch-series was done with mm-unstable as of 11-18-2024,
commit 5a7056135bb6, without and with this patch-series.
Data was gathered on an Intel Sapphire Rapids server, dual-socket 56 cores
per socket, 4 IAA devices per socket, 503 GiB RAM and 525G SSD disk
partition swap. Core frequency was fixed at 2500MHz.
Other kernel configuration parameters:
zswap compressor : zstd, deflate-iaa
zswap allocator : zsmalloc
vm.page-cluster : 2
IAA "compression verification" is enabled and IAA is run in the sync mode.
1WQ is configured per IAA device, and handles both, compressions and
decompressions.
Regression testing (usemem30):
==============================
The vm-scalability "usemem" test was run in a cgroup whose memory.high
was fixed at 150G. The is no swap limit set for the cgroup. 30 usemem
processes were run, each allocating and writing 10G of memory, and sleeping
for 10 sec before exiting:
usemem --init-time -w -O -s 10 -n 30 10g
4k folios: zstd:
================
-------------------------------------------------------------------------------
mm-unstable-11-18-2024 v1 of this patch-series
Patch 1 Patch 2
-------------------------------------------------------------------------------
zswap compressor zstd zstd zstd
vm.page-cluster 2 2 2
-------------------------------------------------------------------------------
Total throughput (KB/s) 4,783,479 4,755,909 4,868,751
Avg throughput (KB/s) 159,449 158,530 162,291
elapsed time (sec) 127.46 129.70 125.70
sys time (sec) 3,088.65 3,143.92 3,071.41
-------------------------------------------------------------------------------
memcg_high 437,178 428,090 451,918
memcg_swap_fail 0 0 0
zswpout 48,931,290 48,931,325 48,932,080
zswpin 390 398 380
pswpout 0 0 0
pswpin 0 0 0
thp_swpout 0 0 0
thp_swpout_fallback 0 0 0
pgmajfault 3,231 3,636 3,627
swap_ra 93 90 91
swap_ra_hit 48 43 48
-------------------------------------------------------------------------------
4k folios: deflate-iaa:
=======================
-------------------------------------------------------------------------------
mm-unstable-11-18-2024 v1 of this patch-series
Patch 1 Patch 2
-------------------------------------------------------------------------------
zswap compressor deflate-iaa deflate-iaa deflate-iaa
vm.page-cluster 2 2 2
-------------------------------------------------------------------------------
Total throughput (KB/s) 5,155,471 5,397,318 5,231,233
Avg throughput (KB/s) 171,849 179,910 174,374
elapsed time (sec) 108.35 104.93 107.81
sys time (sec) 2,400.32 2,293.43 2,395.95
-------------------------------------------------------------------------------
memcg_high 670,635 634,770 632,160
memcg_swap_fail 0 0 0
zswpout 62,098,929 57,334,719 58,221,779
zswpin 425 402 392
pswpout 0 0 0
pswpin 0 0 0
thp_swpout 0 0 0
thp_swpout_fallback 0 0 0
pgmajfault 3,271 3,641 3,632
swap_ra 103 101 93
swap_ra_hit 47 48 45
-------------------------------------------------------------------------------
16k/32/64k folios: zstd:
========================
-------------------------------------------------------------------------------
mm-unstable-11-18-2024 v1 of this patch-series
Patch 1 Patch 2
-------------------------------------------------------------------------------
zswap compressor zstd zstd zstd
vm.page-cluster 2 2 2
-------------------------------------------------------------------------------
Total throughput (KB/s) 6,284,634 6,227,125 6,221,686
Avg throughput (KB/s) 209,487 207,570 207,389
elapsed time (sec) 107.64 110.57 109.96
sys time (sec) 2,566.69 2,636.39 2,615.76
-------------------------------------------------------------------------------
memcg_high 477,219 476,572 477,768
memcg_swap_fail 1,040 1,089 1,088
zswpout 48,931,670 48,931,991 48,931,829
zswpin 384 400 397
pswpout 0 0 0
pswpin 0 0 0
thp_swpout 0 0 0
thp_swpout_fallback 0 0 0
16kB-swpout_fallback 0 0 0
32kB_swpout_fallback 0 0 0
64kB_swpout_fallback 1,040 1,089 1,088
pgmajfault 3,258 3,271 3,265
swap_ra 95 106 101
swap_ra_hit 46 56 54
ZSWPOUT-16kB 2 3 5
ZSWPOUT-32kB 0 1 1
ZSWPOUT-64kB 3,057,203 3,057,162 3,057,147
SWPOUT-16kB 0 0 0
SWPOUT-32kB 0 0 0
SWPOUT-64kB 0 0 0
-------------------------------------------------------------------------------
16k/32/64k folios: deflate-iaa:
===============================
-------------------------------------------------------------------------------
mm-unstable-11-18-2024 v1 of this patch-series
Patch 1 Patch 2
-------------------------------------------------------------------------------
zswap compressor deflate-iaa deflate-iaa deflate-iaa
vm.page-cluster 2 2 2
-------------------------------------------------------------------------------
Total throughput (KB/s) 7,149,906 7,268,900 7,126,761
Avg throughput (KB/s) 238,330 242,296 237,558
elapsed time (sec) 84.38 87.44 84.18
sys time (sec) 1,844.32 1,847.65 1,741.97
-------------------------------------------------------------------------------
memcg_high 616,897 704,278 585,911
memcg_swap_fail 2,734 1,858 1,708
zswpout 55,520,017 60,188,111 52,639,745
zswpin 491 393 444
pswpout 0 0 0
pswpin 0 0 0
thp_swpout 0 0 0
thp_swpout_fallback 0 0 0
16kB-swpout_fallback 0 0 0
32kB_swpout_fallback 0 0 0
64kB_swpout_fallback 2,734 1,858 1,708
pgmajfault 3,314 3,266 3,277
swap_ra 128 103 154
swap_ra_hit 49 46 90
ZSWPOUT-16kB 4 4 3
ZSWPOUT-32kB 2 1 1
ZSWPOUT-64kB 3,467,400 3,759,882 3,288,260
SWPOUT-16kB 0 0 0
SWPOUT-32kB 0 0 0
SWPOUT-64kB 0 0 0
-------------------------------------------------------------------------------
2M folios: zstd:
================
-------------------------------------------------------------------------------
mm-unstable-11-18-2024 v1 of this patch-series
Patch 1 Patch 2
-------------------------------------------------------------------------------
zswap compressor zstd zstd zstd
vm.page-cluster 2 2 2
-------------------------------------------------------------------------------
Total throughput (KB/s) 6,466,700 6,544,384 6,532,820
Avg throughput (KB/s) 215,556 218,146 217,760
elapsed time (sec) 106.80 106.29 105.45
sys time (sec) 2,420.88 2,462.67 2,380.86
-------------------------------------------------------------------------------
memcg_high 60,926 58,746 62,680
memcg_swap_fail 44 62 60
zswpout 48,892,828 48,936,840 48,934,265
zswpin 391 406 391
pswpout 0 0 0
pswpin 0 0 0
thp_swpout 0 0 0
thp_swpout_fallback 44 62 60
pgmajfault 4,907 4,793 5,461
swap_ra 5,070 4,693 6,605
swap_ra_hit 5,024 4,639 6,556
ZSWPOUT-2048kB 95,442 95,509 95,506
SWPOUT-2048kB 0 0 0
-------------------------------------------------------------------------------
2M folios: deflate-iaa:
=======================
-------------------------------------------------------------------------------
mm-unstable-11-18-2024 v1 of this patch-series
Patch 1 Patch 2
-------------------------------------------------------------------------------
zswap compressor deflate-iaa deflate-iaa deflate-iaa
vm.page-cluster 2 2 2
-------------------------------------------------------------------------------
Total throughput (KB/s) 7,245,936 7,589,698 7,470,639
Avg throughput (KB/s) 241,531 252,989 249,021
elapsed time (sec) 84.44 82.77 82.54
sys time (sec) 1,753.41 1,681.53 1,674.63
-------------------------------------------------------------------------------
memcg_high 79,259 85,642 84,382
memcg_swap_fail 139 1,429 2,163
zswpout 57,701,156 59,347,201 58,657,587
zswpin 419 467 469
pswpout 0 0 0
pswpin 0 0 0
thp_swpout 0 0 0
thp_swpout_fallback 139 1,429 2,163
pgmajfault 11,542 19,689 28,301
swap_ra 24,613 47,622 73,288
swap_ra_hit 24,555 47,535 73,203
ZSWPOUT-2048kB 112,515 114,659 112,860
SWPOUT-2048kB 0 0 0
-------------------------------------------------------------------------------
Summary:
========
There are no noticeable performance regressions with this patch series.
Changes in v1:
==============
1) Addressed code review comments from Yosry and Johannes in [2]. Thanks
both!
[1]: https://patchwork.kernel.org/project/linux-mm/list/?series=911935
[2]: https://patchwork.kernel.org/project/linux-mm/patch/20241123070127.332773-11-kanchana.p.sridhar@xxxxxxxxx/
Thanks,
Kanchana
Kanchana P Sridhar (2):
mm: zswap: Modified zswap_store_page() to process multiple pages in a
folio.
mm: zswap: zswap_store_pages() simplifications for batching.
include/linux/zswap.h | 1 +
mm/zswap.c | 199 ++++++++++++++++++++++++++++--------------
2 files changed, 135 insertions(+), 65 deletions(-)
base-commit: 5a7056135bb69da2ce0a42eb8c07968c1331777b
--
2.27.0
