Re: [PATCH v2] ext4: dynamical adjust the length of zero-out chunk
From: Zach Brown <hidden>
Date: 2012-08-13 17:32:32
I also reworded the commit description slightly, and this is what I currently have in my tree. What do people think?
(well, you asked! :))
we allow it to be tunable via sysfs and set an initial default value
of 32, so instead of creating uninitalized extents smaller thans/32/16/?
256k (assuming a 4k block size), they will be zeroed out instead.
Having to qualify the zeroout len with the block size caught my attention!
quoted hunk ↗ jump to hunk
--- a/fs/ext4/super.c +++ b/fs/ext4/super.c@@ -2541,6 +2541,7 @@ EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs); EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request); EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc); EXT4_RW_ATTR_SBI_UI(max_writeback_mb_bump, s_max_writeback_mb_bump); +EXT4_RW_ATTR_SBI_UI(extent_zeroout_len, s_extent_zeroout_len); EXT4_ATTR(trigger_fs_error, 0200, NULL, trigger_test_error);
"len" seems to stand out amongst all those "mb" names :) It'd be nice to define the tunable in terms of some fixed unit, kb or mb, whatever, and then translate to the block size in the code so people don't have to do that math by hand. No? - z