Currently, a hotplug bridge will be given hpmemsize additional memory if available, in order to satisfy any future hotplug allocation requirements. These calculations don't consider the current memory size of the hotplug bridge/slot, so hotplug bridges/slots which have downstream devices will get their current allocation in addition to the hpmemsize value. This makes for possibly undesirable results with a mix of unoccupied and occupied slots (ex, with hpmemsize=2M): 02:03.0 PCI bridge: <-- Occupied Memory behind bridge: d6200000-d64fffff [size=3M] 02:04.0 PCI bridge: <-- Unoccupied Memory behind bridge: d6500000-d66fffff [size=2M] This change considers the current allocation size when using the hpmemsize parameter to make the reservations predictable for the mix of unoccupied and occupied slots: 02:03.0 PCI bridge: <-- Occupied Memory behind bridge: d6200000-d63fffff [size=2M] 02:04.0 PCI bridge: <-- Unoccupied Memory behind bridge: d6400000-d65fffff [size=2M] Signed-off-by: Jon Derrick <jonathan.derrick@xxxxxxxxx> --- Original RFC here: https://patchwork.ozlabs.org/patch/945374/ I split this bit out from the RFC while awaiting the pci string handling enhancements to handle per-device settings Changed from RFC is a simpler algo drivers/pci/setup-bus.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index 79b1824..5ae39e6 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -831,7 +831,8 @@ static resource_size_t calculate_iosize(resource_size_t size, static resource_size_t calculate_memsize(resource_size_t size, resource_size_t min_size, - resource_size_t size1, + resource_size_t add_size, + resource_size_t children_add_size, resource_size_t old_size, resource_size_t align) { @@ -841,7 +842,7 @@ static resource_size_t calculate_memsize(resource_size_t size, old_size = 0; if (size < old_size) size = old_size; - size = ALIGN(size + size1, align); + size = ALIGN(max(size, add_size) + children_add_size, align); return size; } @@ -1079,12 +1080,10 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, min_align = calculate_mem_align(aligns, max_order); min_align = max(min_align, window_alignment(bus, b_res->flags)); - size0 = calculate_memsize(size, min_size, 0, resource_size(b_res), min_align); + size0 = calculate_memsize(size, min_size, 0, 0, resource_size(b_res), min_align); add_align = max(min_align, add_align); - if (children_add_size > add_size) - add_size = children_add_size; - size1 = (!realloc_head || (realloc_head && !add_size)) ? size0 : - calculate_memsize(size, min_size, add_size, + size1 = (!realloc_head || (realloc_head && !add_size && !children_add_size)) ? size0 : + calculate_memsize(size, min_size, add_size, children_add_size, resource_size(b_res), add_align); if (!size0 && !size1) { if (b_res->start || b_res->end) -- 1.8.3.1
