The default value appears to have been corrected by "f2fs: fix wrong percentage" commit[1], but still the old values in the f2fs document[2]. ref: 1: https://github.com/torvalds/linux/commit/29710bcf9426c84bb6a9b1d94316895ed6143813 2: https://www.kernel.org/doc/Documentation/filesystems/f2fs.txt introduces ram_thresh: https://lore.kernel.org/patchwork/patch/450476/ define DEF_RAM_THRESHOLD 1: https://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs-stable.git/tree/fs/f2fs/node.h?h=linux-4.19.y#n23
Thanks for the report, I've sent a patch for this issue. https://lore.kernel.org/linux-f2fs-devel/20191022092611.58191-1-yuchao0@huawei.com/T/#u
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=4c3258b9b0fff24623a6e95381e1112cc290abd4