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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH 2/2] xen/arm: Handle reserved heap pages in boot and heap allocator
On Wed, 24 Aug 2022, Henry Wang wrote:
> This commit firstly adds a global variable `reserved_heap`.
> This newly introduced global variable is set at the device tree
> parsing time if the reserved heap ranges are defined in the device
> tree chosen node.
>
> For Arm32, In `setup_mm`, if the reserved heap is enabled, we use
> the reserved heap region for both domheap and xenheap allocation.
>
> For Arm64, In `setup_mm`, if the reserved heap is enabled and used,
> we make sure that only these reserved heap pages are added to the
> boot allocator. These reserved heap pages in the boot allocator are
> added to the heap allocator at `end_boot_allocator()`.
>
> If the reserved heap is disabled, we stick to current page allocation
> strategy at boot time.
>
> Also, take the chance to correct a "double not" print in Arm32
> `setup_mm()`.
>
> Signed-off-by: Henry Wang <Henry.Wang@xxxxxxx>
> ---
> With reserved heap enabled, for Arm64, naming of global variables such
> as `xenheap_mfn_start` and `xenheap_mfn_end` seems to be ambiguous,
> wondering if we should rename these variables.
> ---
> Changes from RFC to v1:
> - Rebase on top of latest `setup_mm()` changes.
> - Added Arm32 logic in `setup_mm()`.
> ---
> xen/arch/arm/bootfdt.c | 2 +
> xen/arch/arm/include/asm/setup.h | 2 +
> xen/arch/arm/setup.c | 79 +++++++++++++++++++++++++-------
> 3 files changed, 67 insertions(+), 16 deletions(-)
>
> diff --git a/xen/arch/arm/bootfdt.c b/xen/arch/arm/bootfdt.c
> index 33704ca487..ab73b6e212 100644
> --- a/xen/arch/arm/bootfdt.c
> +++ b/xen/arch/arm/bootfdt.c
> @@ -325,6 +325,8 @@ static int __init process_chosen_node(const void *fdt,
> int node,
> true);
> if ( rc )
> return rc;
> +
> + reserved_heap = true;
> }
>
> printk("Checking for initrd in /chosen\n");
> diff --git a/xen/arch/arm/include/asm/setup.h
> b/xen/arch/arm/include/asm/setup.h
> index e80f3d6201..00536a6d55 100644
> --- a/xen/arch/arm/include/asm/setup.h
> +++ b/xen/arch/arm/include/asm/setup.h
> @@ -92,6 +92,8 @@ extern struct bootinfo bootinfo;
>
> extern domid_t max_init_domid;
>
> +extern bool reserved_heap;
> +
> void copy_from_paddr(void *dst, paddr_t paddr, unsigned long len);
>
> size_t estimate_efi_size(unsigned int mem_nr_banks);
> diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
> index 500307edc0..fe76cf6325 100644
> --- a/xen/arch/arm/setup.c
> +++ b/xen/arch/arm/setup.c
> @@ -73,6 +73,8 @@ integer_param("xenheap_megabytes", opt_xenheap_megabytes);
>
> domid_t __read_mostly max_init_domid;
>
> +bool __read_mostly reserved_heap;
> +
> static __used void init_done(void)
> {
> /* Must be done past setting system_state. */
> @@ -699,8 +701,10 @@ static void __init populate_boot_allocator(void)
> #ifdef CONFIG_ARM_32
> static void __init setup_mm(void)
> {
> - paddr_t ram_start, ram_end, ram_size, e;
> - unsigned long ram_pages;
> + paddr_t ram_start, ram_end, ram_size, e, bank_start, bank_end, bank_size;
> + paddr_t reserved_heap_start = ~0, reserved_heap_end = 0,
INVALID_PADDR or ~0ULL
> + reserved_heap_size = 0;
> + unsigned long ram_pages, reserved_heap_pages = 0;
> unsigned long heap_pages, xenheap_pages, domheap_pages;
> unsigned int i;
> const uint32_t ctr = READ_CP32(CTR);
> @@ -720,9 +724,9 @@ static void __init setup_mm(void)
>
> for ( i = 1; i < bootinfo.mem.nr_banks; i++ )
> {
> - paddr_t bank_start = bootinfo.mem.bank[i].start;
> - paddr_t bank_size = bootinfo.mem.bank[i].size;
> - paddr_t bank_end = bank_start + bank_size;
> + bank_start = bootinfo.mem.bank[i].start;
> + bank_size = bootinfo.mem.bank[i].size;
> + bank_end = bank_start + bank_size;
>
> ram_size = ram_size + bank_size;
> ram_start = min(ram_start,bank_start);
> @@ -731,6 +735,25 @@ static void __init setup_mm(void)
>
> total_pages = ram_pages = ram_size >> PAGE_SHIFT;
>
> + if ( reserved_heap )
> + {
> + for ( i = 0 ; i < bootinfo.reserved_mem.nr_banks; i++ )
> + {
> + if ( bootinfo.reserved_mem.bank[i].xen_heap )
> + {
> + bank_start = bootinfo.reserved_mem.bank[i].start;
> + bank_size = bootinfo.reserved_mem.bank[i].size;
> + bank_end = bank_start + bank_size;
> +
> + reserved_heap_size += bank_size;
> + reserved_heap_start = min(reserved_heap_start, bank_start);
> + reserved_heap_end = max(reserved_heap_end, bank_end);
> + }
> + }
> +
> + reserved_heap_pages = reserved_heap_size >> PAGE_SHIFT;
> + }
> +
> /*
> * If the user has not requested otherwise via the command line
> * then locate the xenheap using these constraints:
> @@ -743,7 +766,8 @@ static void __init setup_mm(void)
> * We try to allocate the largest xenheap possible within these
> * constraints.
> */
> - heap_pages = ram_pages;
> + heap_pages = !reserved_heap ? ram_pages : reserved_heap_pages;
> +
> if ( opt_xenheap_megabytes )
> xenheap_pages = opt_xenheap_megabytes << (20-PAGE_SHIFT);
> else
> @@ -755,17 +779,21 @@ static void __init setup_mm(void)
>
> do
> {
> - e = consider_modules(ram_start, ram_end,
> + e = !reserved_heap ?
> + consider_modules(ram_start, ram_end,
> pfn_to_paddr(xenheap_pages),
> - 32<<20, 0);
> + 32<<20, 0) :
> + reserved_heap_end;
> +
> if ( e )
> break;
>
> xenheap_pages >>= 1;
> } while ( !opt_xenheap_megabytes && xenheap_pages > 32<<(20-PAGE_SHIFT)
> );
>
> - if ( ! e )
> - panic("Not not enough space for xenheap\n");
> + if ( ! e ||
> + ( reserved_heap && reserved_heap_pages < 32<<(20-PAGE_SHIFT) ) )
> + panic("Not enough space for xenheap\n");
I would skip the do/while loop completely if reserved_heap. We don't
need it anyway and we can automatically calculate xenheap_pages in a
single line.
> domheap_pages = heap_pages - xenheap_pages;
>
> @@ -810,9 +838,9 @@ static void __init setup_mm(void)
> static void __init setup_mm(void)
> {
> const struct meminfo *banks = &bootinfo.mem;
> - paddr_t ram_start = ~0;
> - paddr_t ram_end = 0;
> - paddr_t ram_size = 0;
> + paddr_t ram_start = ~0, bank_start = ~0;
> + paddr_t ram_end = 0, bank_end = 0;
> + paddr_t ram_size = 0, bank_size = 0;
> unsigned int i;
Please use INVALID_PADDR or ~0ULL
>
> init_pdx();
> @@ -821,17 +849,36 @@ static void __init setup_mm(void)
> * We need some memory to allocate the page-tables used for the xenheap
> * mappings. But some regions may contain memory already allocated
> * for other uses (e.g. modules, reserved-memory...).
> - *
> + * If reserved heap regions are properly defined, (only) add these
> regions
> + * in the boot allocator.
> + */
> + if ( reserved_heap )
> + {
> + for ( i = 0 ; i < bootinfo.reserved_mem.nr_banks; i++ )
> + {
> + if ( bootinfo.reserved_mem.bank[i].xen_heap )
> + {
> + bank_start = bootinfo.reserved_mem.bank[i].start;
> + bank_size = bootinfo.reserved_mem.bank[i].size;
> + bank_end = bank_start + bank_size;
> +
> + init_boot_pages(bank_start, bank_end);
> + }
> + }
> + }
> + /*
> + * No reserved heap regions:
> * For simplicity, add all the free regions in the boot allocator.
> */
> - populate_boot_allocator();
> + else
> + populate_boot_allocator();
>
> total_pages = 0;
>
> for ( i = 0; i < banks->nr_banks; i++ )
> {
> const struct membank *bank = &banks->bank[i];
> - paddr_t bank_end = bank->start + bank->size;
> + bank_end = bank->start + bank->size;
>
> ram_size = ram_size + bank->size;
> ram_start = min(ram_start, bank->start);
> --
> 2.17.1
>
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