Re: [PATCH net-next v9 00/17] net: macb: implement context swapping
From: Théo Lebrun <theo.lebrun@bootlin.com>
Date: 2026-08-15 09:31:18
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On Wed Aug 12, 2026 at 10:03 AM CEST, Théo Lebrun wrote:
MACB has a pretty primitive approach to buffer management. They are all stored in `struct macb *bp`. On operations that require buffer realloc (set_ringparam & change_mtu at the moment), the only option is to close the interface, change our global state and re-open the interface. Two issues: - It doesn't fly on memory pressured systems; we free our precious buffers and don't manage to reallocate fully, meaning our machine just lost its network access. - Anecdotally, it is pretty slow because it implies a full PHY reinit. Instead, we shall: - allocate a new context (including buffers) first - if it fails, early return without any impact to the interface - stop interface - update global state (bp, netdev, etc) - pass newly allocated buffer pointers to the hardware - start interface - free old context This is what we implement here. Both .set_ringparam() and .ndo_change_mtu() are covered by this series. In the future, at least .set_channels() [0], XDP [1] and XSK [2] would benefit.
Sorry for the insistence, but do we have a chance of seeing this merged before the next merge window? Context swapping is a nice feature to get into v7.3 and it would allow us to send XDP (& XSK) series that are dependent on context swapping. Thanks! Have a nice week-end, -- Théo Lebrun, Bootlin Embedded Linux and Kernel engineering https://bootlin.com