On Wed, Apr 20, 2022 at 4:09 PM Patrick Daly <quic_pdaly@xxxxxxxxxxx> wrote: > > The reserved_mem array must be statically allocated because it is used > prior to memblock being aware of all "no-map" or otherwise reserved > regions which have fixed physical addresses. Due to this limitation, > if one architecture/board has a large number of reserved_mem regions, > this limit must be raised for all. > > In particular, certain new qcom boards currently have 63 reserved memory > regions, which when new features are added, pushes them over the existing > limit of 64. Please revive this instead: https://lore.kernel.org/all/20211119075844.2902592-3-calvinzhang.cool@xxxxxxxxx/ > > A generalized breakdown by region type: > 13 for linux-loaded device firmware If loaded by linux, why do you need fixed carveouts in DT? The devices can't be told what address their fw is at? > 9 for guest-vms or inter-vm communication Why does that need to be in DT? > 15 cma heaps/dma-buf heaps Sounds like not trusting the OS to allocate memory itself. From what I've read, the kernel's memory allocation abilities are better now than when CMA was added. > 24 for bootloaders/hypervisor/secure-world devices or software > 2 misc > > Although this number could be reduced by a minor amount by combining > physically adjacent regions, this comes at the cost of losing > documention on what/who the regions are used by. In addition, combining > adjacent regions is not possible if there are phandles in devicetree > referring to the regions in question, such as "memory-region". > > Vmlinux before: > text data bss dec hex filename > 31030829 15807732 588524 47427085 2d3ae0d dist/vmlinux > > Vmlinux after: > text data bss dec hex filename > 31030877 15807668 592108 47430653 2d3bbfd dist/vmlinux > > Signed-off-by: Patrick Daly <quic_pdaly@xxxxxxxxxxx> > --- > drivers/of/of_reserved_mem.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c > index 75caa6f..de0cdda 100644 > --- a/drivers/of/of_reserved_mem.c > +++ b/drivers/of/of_reserved_mem.c > @@ -26,7 +26,7 @@ > > #include "of_private.h" > > -#define MAX_RESERVED_REGIONS 64 > +#define MAX_RESERVED_REGIONS 128 > static struct reserved_mem reserved_mem[MAX_RESERVED_REGIONS]; > static int reserved_mem_count; > > -- > 2.7.4 >
