Hi, Barry, Barry Song <21cnbao@xxxxxxxxx> writes: > From: Barry Song <v-songbaohua@xxxxxxxx> > > When large folios are compressed at a larger granularity, we observe > a notable reduction in CPU usage and a significant improvement in > compression ratios. > > mTHP's ability to be swapped out without splitting and swapped back in > as a whole allows compression and decompression at larger granularities. > > This patchset enhances zsmalloc and zram by adding support for dividing > large folios into multi-page blocks, typically configured with a > 2-order granularity. Without this patchset, a large folio is always > divided into `nr_pages` 4KiB blocks. > > The granularity can be set using the `ZSMALLOC_MULTI_PAGES_ORDER` > setting, where the default of 2 allows all anonymous THP to benefit. > > Examples include: > * A 16KiB large folio will be compressed and stored as a single 16KiB > block. > * A 64KiB large folio will be compressed and stored as four 16KiB > blocks. > > For example, swapping out and swapping in 100MiB of typical anonymous > data 100 times (with 16KB mTHP enabled) using zstd yields the following > results: > > w/o patches w/ patches > swap-out time(ms) 68711 49908 > swap-in time(ms) 30687 20685 > compression ratio 20.49% 16.9% The data looks good. Thanks! Have you considered the situation that the large folio fails to be allocated during swap-in? It's possible because the memory may be very fragmented. > -v2: > While it is not mature yet, I know some people are waiting for > an update :-) > * Fixed some stability issues. > * rebase againest the latest mm-unstable. > * Set default order to 2 which benefits all anon mTHP. > * multipages ZsPageMovable is not supported yet. > > Tangquan Zheng (2): > mm: zsmalloc: support objects compressed based on multiple pages > zram: support compression at the granularity of multi-pages > > drivers/block/zram/Kconfig | 9 + > drivers/block/zram/zcomp.c | 17 +- > drivers/block/zram/zcomp.h | 12 +- > drivers/block/zram/zram_drv.c | 450 +++++++++++++++++++++++++++++++--- > drivers/block/zram/zram_drv.h | 45 ++++ > include/linux/zsmalloc.h | 10 +- > mm/Kconfig | 18 ++ > mm/zsmalloc.c | 232 +++++++++++++----- > 8 files changed, 699 insertions(+), 94 deletions(-) -- Best Regards, Huang, Ying
