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f2cbd48528
after 'police' configuration parameters were converted to use RCU instead of spinlock, the state variables used to compute the traffic rate (namely 'tcfp_toks', 'tcfp_ptoks' and 'tcfp_t_c') are erroneously read/updated in the traffic path without any protection. Use a dedicated spinlock to avoid race conditions on these variables, and ensure proper cache-line alignment. In this way, 'police' is still faster than what we observed when 'tcf_lock' was used in the traffic path _ i.e. reverting commit2d550dbad8("net/sched: act_police: don't use spinlock in the data path"). Moreover, we preserve the throughput improvement that was obtained after 'police' started using per-cpu counters, when 'avrate' is used instead of 'rate'. Changes since v1 (thanks to Eric Dumazet): - call ktime_get_ns() before acquiring the lock in the traffic path - use a dedicated spinlock instead of tcf_lock - improve cache-line usage Fixes:2d550dbad8("net/sched: act_police: don't use spinlock in the data path") Reported-and-suggested-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Davide Caratti <dcaratti@redhat.com> Reviewed-by: Eric Dumazet <edumazet@google.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.