169f5eb288
Use a spinlock to protect hba->outstanding_reqs instead of using atomic operations to update this member variable. This patch is a performance improvement because it reduces the number of atomic operations in the hot path (test_and_clear_bit()) and because it reduces the lock contention on the SCSI host lock. On my test setup this patch improves IOPS by about 1%. Link: https://lore.kernel.org/r/20210722033439.26550-14-bvanassche@acm.org Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Stanley Chu <stanley.chu@mediatek.com> Cc: Can Guo <cang@codeaurora.org> Cc: Asutosh Das <asutoshd@codeaurora.org> Cc: Avri Altman <avri.altman@wdc.com> Reviewed-by: Daejun Park <daejun7.park@samsung.com> Reviewed-by: Bean Huo <beanhuo@micron.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.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.