f728760aa9
There are stressful update of cluster allocation bitmap when using dirsync mount option which is doing sync buffer on every cluster bit clearing. This could result in performance degradation when deleting big size file. Fix to update only when the bitmap buffer index is changed would make less disk access, improving performance especially for truncate operation. Testing with Samsung 256GB sdcard, mounted with dirsync option (mount -t exfat /dev/block/mmcblk0p1 /temp/mount -o dirsync) Remove 4GB file, blktrace result. [Before] : 39 secs. Total (blktrace): Reads Queued: 0, 0KiB Writes Queued: 32775, 16387KiB Read Dispatches: 0, 0KiB Write Dispatches: 32775, 16387KiB Reads Requeued: 0 Writes Requeued: 0 Reads Completed: 0, 0KiB Writes Completed: 32775, 16387KiB Read Merges: 0, 0KiB Write Merges: 0, 0KiB IO unplugs: 2 Timer unplugs: 0 [After] : 1 sec. Total (blktrace): Reads Queued: 0, 0KiB Writes Queued: 13, 6KiB Read Dispatches: 0, 0KiB Write Dispatches: 13, 6KiB Reads Requeued: 0 Writes Requeued: 0 Reads Completed: 0, 0KiB Writes Completed: 13, 6KiB Read Merges: 0, 0KiB Write Merges: 0, 0KiB IO unplugs: 1 Timer unplugs: 0 Signed-off-by: Hyeongseok Kim <hyeongseok@gmail.com> Acked-by: Sungjong Seo <sj1557.seo@samsung.com> Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
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 Restructured Text 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.