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[ Upstream commit 868a1e863f95183f00809363fefba6d4f5bcd116 ] If all free RB queues are empty, the driver will never restock the free RB queue. That's because the restocking happens in the Rx flow, and if the free queue is empty there will be no Rx. Although there's a background worker (a.k.a. allocator) allocating memory for RBs so that the Rx handler can restock them, the worker may run only after the free queue has become empty (and then it is too late for restocking as explained above). There is a solution for that called 'emergency': If the number of used RB's reaches half the amount of all RB's, the Rx handler will not wait for the allocator but immediately allocate memory for the used RB's and restock the free queue. But, since the used RB's is per queue, it may happen that the used RB's are spread between the queues such that the emergency check will fail for each of the queues (and still run out of RBs, causing the above symptom). To fix it, move to emergency mode if the sum of *all* used RBs (for all Rx queues) reaches half the amount of all RB's Signed-off-by: Shaul Triebitz <shaul.triebitz@intel.com> Signed-off-by: Luca Coelho <luciano.coelho@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.