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Given the mechanism to unwind and replay requests (designed to support preemption), we have an alternative to the current method of resubmitting the ELSP upon reset. Resubmitting ELSP turns out to be more complicated than expected, due to having to handle lost context-switch interrupts and so guessing what ELSP we need to resubmit later. Instead, by unwinding the requests and clearing the ELSP tracking entirely, we can then just dequeue the first pair of ready requests after resetting, using the normal submission procedure. Currently, the unwound requests have maximum priority and so are guaranteed to be resubmitted upon resume. If we are lucky, we may be able to coalesce a new request on top! Suggested-by: Michał Winiarski <michal.winiarski@intel.com> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Michał Winiarski <michal.winiarski@intel.com> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20170916204414.32762-4-chris@chris-wilson.co.uk Reviewed-by: Michał Winiarski <michal.winiarski@intel.com>
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.