4373a5e260
Eric Dumazet says: ==================== net/packet: better behavior under DDOS Using tcpdump (or other af_packet user) on a busy host can lead to catastrophic consequences, because suddenly, potentially all cpus are spinning on a contended spinlock. Both packet_rcv() and tpacket_rcv() grab the spinlock to eventually find there is no room for an additional packet. This patch series align packet_rcv() and tpacket_rcv() to both check if the queue is full before grabbing the spinlock. If the queue is full, they both increment a new atomic counter placed on a separate cache line to let readers drain the queue faster. There is still false sharing on this new atomic counter, we might in the future make it per cpu if there is interest. ==================== Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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.