1
linux/fs/erofs
Chunhai Guo d9281660ff erofs: relaxed temporary buffers allocation on readahead
Even with inplace decompression, sometimes very few temporary buffers
may be still needed for a single decompression shot (e.g. 16 pages for
64k sliding window or 4 pages for 16k sliding window).  In low-memory
scenarios, it would be better to try to allocate with GFP_NOWAIT on
readahead first.  That can help reduce the time spent on page allocation
under durative memory pressure.

Here are detailed performance numbers under multi-app launch benchmark
workload [1] on ARM64 Android devices (8-core CPU and 8GB of memory)
running a 5.15 LTS kernel with EROFS of 4k pclusters:

+----------------------------------------------+
|      LZ4       | vanilla | patched |  diff   |
|----------------+---------+---------+---------|
|  Average (ms)  |  3364   |  2684   | -20.21% | [64k sliding window]
|----------------+---------+---------+---------|
|  Average (ms)  |  2079   |  1610   | -22.56% | [16k sliding window]
+----------------------------------------------+

The total size of system images for 4k pclusters is almost unchanged:
(64k sliding window)  9,117,044 KB
(16k sliding window)  9,113,096 KB

Therefore, in addition to switch the sliding window from 64k to 16k,
after applying this patch, it can eventually save 52.14% (3364 -> 1610)
on average with no memory reservation.  That is particularly useful for
embedded devices with limited resources.

[1] https://lore.kernel.org/r/20240109074143.4138783-1-guochunhai@vivo.com

Suggested-by: Gao Xiang <xiang@kernel.org>
Signed-off-by: Chunhai Guo <guochunhai@vivo.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Yue Hu <huyue2@coolpad.com>
Link: https://lore.kernel.org/r/20240126140142.201718-1-hsiangkao@linux.alibaba.com
2024-01-27 12:28:08 +08:00
..
compress.h erofs: relaxed temporary buffers allocation on readahead 2024-01-27 12:28:08 +08:00
data.c erofs: fix NULL dereference of dif->bdev_handle in fscache mode 2023-11-17 19:55:46 +08:00
decompressor_deflate.c erofs: relaxed temporary buffers allocation on readahead 2024-01-27 12:28:08 +08:00
decompressor_lzma.c erofs: relaxed temporary buffers allocation on readahead 2024-01-27 12:28:08 +08:00
decompressor.c erofs: relaxed temporary buffers allocation on readahead 2024-01-27 12:28:08 +08:00
dir.c
erofs_fs.h erofs: update on-disk format for xattr name filter 2023-08-11 12:11:44 +08:00
fscache.c erofs: get rid of unneeded GFP_NOFS 2024-01-25 11:24:19 +08:00
inode.c erofs: get rid of unneeded GFP_NOFS 2024-01-25 11:24:19 +08:00
internal.h Changes since last update: 2023-11-02 07:53:57 -10:00
Kconfig netfs, fscache: Combine fscache with netfs 2023-12-24 15:08:46 +00:00
Makefile erofs: DEFLATE compression support 2023-08-11 12:11:17 +08:00
namei.c
pcpubuf.c
super.c erofs: make erofs_{err,info}() support NULL sb parameter 2024-01-10 19:59:39 +08:00
sysfs.c
utils.c erofs: get rid of unneeded GFP_NOFS 2024-01-25 11:24:19 +08:00
xattr.c erofs: move erofs_xattr_handlers and xattr_handler_map to .rodata 2023-10-09 16:24:17 +02:00
xattr.h erofs: move erofs_xattr_handlers and xattr_handler_map to .rodata 2023-10-09 16:24:17 +02:00
zdata.c erofs: relaxed temporary buffers allocation on readahead 2024-01-27 12:28:08 +08:00
zmap.c Changes since last update: 2024-01-18 18:12:26 -08:00