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e759b5cf70
qlge uses an irq enable/disable refcounting scheme that is: * poorly implemented Uses a spin_lock to protect accesses to the irq_cnt atomic variable. * buggy Breaks when there is not a 1:1 sequence of irq - napi_poll, such as when using SO_BUSY_POLL. * unnecessary The purpose or irq_cnt is to reduce irq control writes when multiple work items result from one irq: the irq is re-enabled after all work is done. Analysis of the irq handler shows that there is only one case where there might be two workers scheduled at once, and those have separate irq masking bits. Therefore, remove irq_cnt. Additionally, we get a performance improvement: perf stat -e cycles -a -r5 super_netperf 100 -H 192.168.33.1 -t TCP_RR Before: 628560 628056 622103 622744 627202 [...] 268,803,947,669 cycles ( +- 0.09% ) After: 636300 634106 634984 638555 634188 [...] 259,237,291,449 cycles ( +- 0.19% ) Signed-off-by: Benjamin Poirier <bpoirier@suse.com> Link: https://lore.kernel.org/r/20190927101210.23856-3-bpoirier@suse.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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.