bb66009958
when writing file with direct_IO on bcachefs, then performance is
much lower than other fs due to write back throttle in block layer:
wbt_wait+1
__rq_qos_throttle+32
blk_mq_submit_bio+394
submit_bio_noacct_nocheck+649
bch2_submit_wbio_replicas+538
__bch2_write+2539
bch2_direct_write+1663
bch2_write_iter+318
aio_write+355
io_submit_one+1224
__x64_sys_io_submit+169
do_syscall_64+134
entry_SYSCALL_64_after_hwframe+110
add set REQ_SYNC and REQ_IDLE in bio->bi_opf as standard dirct-io
Signed-off-by: zhuxiaohui <zhuxiaohui.400@bytedance.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.