Re: [PATCH v2] alpha: switch to NO_BOOTMEM

From: Mike Rapoport
Date: Wed Jul 04 2018 - 08:45:06 EST


Any comments on this?

On Sat, Jun 30, 2018 at 06:13:30PM +0300, Mike Rapoport wrote:
> Replace bootmem allocator with memblock and enable use of NO_BOOTMEM like
> on most other architectures.
>
> Alpha gets the description of the physical memory from the firmware as an
> array of memory clusters. Each cluster that is not reserved by the firmware
> is added to memblock.memory.
>
> Once the memblock.memory is set up, we reserve the kernel and initrd pages
> with memblock reserve.
>
> Since we don't need the bootmem bitmap anymore, the code that finds an
> appropriate place is removed.
>
> The conversion does not take care of NUMA support which is marked broken
> for more than 10 years now.
>
> Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
> ---
> v2: describe the conversion as per Michal's request
>
> Tested with qemu-system-alpha. I've added some tweaks to sys_dp264 to force
> memory split for testing with CONFIG_DISCONTIGMEM=y
>
> The allyesconfig build requires update to DEFERRED_STRUCT_PAGE_INIT
> dependencies [1] which is already in -mm tree.
>
> [1] https://lkml.org/lkml/2018/6/29/353
>
> arch/alpha/Kconfig | 2 +
> arch/alpha/kernel/core_irongate.c | 4 +-
> arch/alpha/kernel/setup.c | 98 ++++-----------------------------
> arch/alpha/mm/numa.c | 113 +++++---------------------------------
> 4 files changed, 29 insertions(+), 188 deletions(-)
>
> diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
> index 04a4a138ed13..040692a8d433 100644
> --- a/arch/alpha/Kconfig
> +++ b/arch/alpha/Kconfig
> @@ -30,6 +30,8 @@ config ALPHA
> select ODD_RT_SIGACTION
> select OLD_SIGSUSPEND
> select CPU_NO_EFFICIENT_FFS if !ALPHA_EV67
> + select HAVE_MEMBLOCK
> + select NO_BOOTMEM
> help
> The Alpha is a 64-bit general-purpose processor designed and
> marketed by the Digital Equipment Corporation of blessed memory,
> diff --git a/arch/alpha/kernel/core_irongate.c b/arch/alpha/kernel/core_irongate.c
> index aec757250e07..f70986683fc6 100644
> --- a/arch/alpha/kernel/core_irongate.c
> +++ b/arch/alpha/kernel/core_irongate.c
> @@ -21,6 +21,7 @@
> #include <linux/init.h>
> #include <linux/initrd.h>
> #include <linux/bootmem.h>
> +#include <linux/memblock.h>
>
> #include <asm/ptrace.h>
> #include <asm/cacheflush.h>
> @@ -241,8 +242,7 @@ albacore_init_arch(void)
> size / 1024);
> }
> #endif
> - reserve_bootmem_node(NODE_DATA(0), pci_mem, memtop -
> - pci_mem, BOOTMEM_DEFAULT);
> + memblock_reserve(pci_mem, memtop - pci_mem);
> printk("irongate_init_arch: temporarily reserving "
> "region %08lx-%08lx for PCI\n", pci_mem, memtop - 1);
> }
> diff --git a/arch/alpha/kernel/setup.c b/arch/alpha/kernel/setup.c
> index 5576f7646fb6..4f0d94471bc9 100644
> --- a/arch/alpha/kernel/setup.c
> +++ b/arch/alpha/kernel/setup.c
> @@ -30,6 +30,7 @@
> #include <linux/ioport.h>
> #include <linux/platform_device.h>
> #include <linux/bootmem.h>
> +#include <linux/memblock.h>
> #include <linux/pci.h>
> #include <linux/seq_file.h>
> #include <linux/root_dev.h>
> @@ -312,9 +313,7 @@ setup_memory(void *kernel_end)
> {
> struct memclust_struct * cluster;
> struct memdesc_struct * memdesc;
> - unsigned long start_kernel_pfn, end_kernel_pfn;
> - unsigned long bootmap_size, bootmap_pages, bootmap_start;
> - unsigned long start, end;
> + unsigned long kernel_size;
> unsigned long i;
>
> /* Find free clusters, and init and free the bootmem accordingly. */
> @@ -322,6 +321,8 @@ setup_memory(void *kernel_end)
> (hwrpb->mddt_offset + (unsigned long) hwrpb);
>
> for_each_mem_cluster(memdesc, cluster, i) {
> + unsigned long end;
> +
> printk("memcluster %lu, usage %01lx, start %8lu, end %8lu\n",
> i, cluster->usage, cluster->start_pfn,
> cluster->start_pfn + cluster->numpages);
> @@ -335,6 +336,9 @@ setup_memory(void *kernel_end)
> end = cluster->start_pfn + cluster->numpages;
> if (end > max_low_pfn)
> max_low_pfn = end;
> +
> + memblock_add(PFN_PHYS(cluster->start_pfn),
> + cluster->numpages << PAGE_SHIFT);
> }
>
> /*
> @@ -363,87 +367,9 @@ setup_memory(void *kernel_end)
> max_low_pfn = mem_size_limit;
> }
>
> - /* Find the bounds of kernel memory. */
> - start_kernel_pfn = PFN_DOWN(KERNEL_START_PHYS);
> - end_kernel_pfn = PFN_UP(virt_to_phys(kernel_end));
> - bootmap_start = -1;
> -
> - try_again:
> - if (max_low_pfn <= end_kernel_pfn)
> - panic("not enough memory to boot");
> -
> - /* We need to know how many physically contiguous pages
> - we'll need for the bootmap. */
> - bootmap_pages = bootmem_bootmap_pages(max_low_pfn);
> -
> - /* Now find a good region where to allocate the bootmap. */
> - for_each_mem_cluster(memdesc, cluster, i) {
> - if (cluster->usage & 3)
> - continue;
> -
> - start = cluster->start_pfn;
> - end = start + cluster->numpages;
> - if (start >= max_low_pfn)
> - continue;
> - if (end > max_low_pfn)
> - end = max_low_pfn;
> - if (start < start_kernel_pfn) {
> - if (end > end_kernel_pfn
> - && end - end_kernel_pfn >= bootmap_pages) {
> - bootmap_start = end_kernel_pfn;
> - break;
> - } else if (end > start_kernel_pfn)
> - end = start_kernel_pfn;
> - } else if (start < end_kernel_pfn)
> - start = end_kernel_pfn;
> - if (end - start >= bootmap_pages) {
> - bootmap_start = start;
> - break;
> - }
> - }
> -
> - if (bootmap_start == ~0UL) {
> - max_low_pfn >>= 1;
> - goto try_again;
> - }
> -
> - /* Allocate the bootmap and mark the whole MM as reserved. */
> - bootmap_size = init_bootmem(bootmap_start, max_low_pfn);
> -
> - /* Mark the free regions. */
> - for_each_mem_cluster(memdesc, cluster, i) {
> - if (cluster->usage & 3)
> - continue;
> -
> - start = cluster->start_pfn;
> - end = cluster->start_pfn + cluster->numpages;
> - if (start >= max_low_pfn)
> - continue;
> - if (end > max_low_pfn)
> - end = max_low_pfn;
> - if (start < start_kernel_pfn) {
> - if (end > end_kernel_pfn) {
> - free_bootmem(PFN_PHYS(start),
> - (PFN_PHYS(start_kernel_pfn)
> - - PFN_PHYS(start)));
> - printk("freeing pages %ld:%ld\n",
> - start, start_kernel_pfn);
> - start = end_kernel_pfn;
> - } else if (end > start_kernel_pfn)
> - end = start_kernel_pfn;
> - } else if (start < end_kernel_pfn)
> - start = end_kernel_pfn;
> - if (start >= end)
> - continue;
> -
> - free_bootmem(PFN_PHYS(start), PFN_PHYS(end) - PFN_PHYS(start));
> - printk("freeing pages %ld:%ld\n", start, end);
> - }
> -
> - /* Reserve the bootmap memory. */
> - reserve_bootmem(PFN_PHYS(bootmap_start), bootmap_size,
> - BOOTMEM_DEFAULT);
> - printk("reserving pages %ld:%ld\n", bootmap_start, bootmap_start+PFN_UP(bootmap_size));
> + /* Reserve the kernel memory. */
> + kernel_size = virt_to_phys(kernel_end) - KERNEL_START_PHYS;
> + memblock_reserve(KERNEL_START_PHYS, kernel_size);
>
> #ifdef CONFIG_BLK_DEV_INITRD
> initrd_start = INITRD_START;
> @@ -459,8 +385,8 @@ setup_memory(void *kernel_end)
> initrd_end,
> phys_to_virt(PFN_PHYS(max_low_pfn)));
> } else {
> - reserve_bootmem(virt_to_phys((void *)initrd_start),
> - INITRD_SIZE, BOOTMEM_DEFAULT);
> + memblock_reserve(virt_to_phys((void *)initrd_start),
> + INITRD_SIZE);
> }
> }
> #endif /* CONFIG_BLK_DEV_INITRD */
> diff --git a/arch/alpha/mm/numa.c b/arch/alpha/mm/numa.c
> index a9e86475f169..26cd925d19b1 100644
> --- a/arch/alpha/mm/numa.c
> +++ b/arch/alpha/mm/numa.c
> @@ -11,6 +11,7 @@
> #include <linux/kernel.h>
> #include <linux/mm.h>
> #include <linux/bootmem.h>
> +#include <linux/memblock.h>
> #include <linux/swap.h>
> #include <linux/initrd.h>
> #include <linux/pfn.h>
> @@ -59,12 +60,10 @@ setup_memory_node(int nid, void *kernel_end)
> struct memclust_struct * cluster;
> struct memdesc_struct * memdesc;
> unsigned long start_kernel_pfn, end_kernel_pfn;
> - unsigned long bootmap_size, bootmap_pages, bootmap_start;
> unsigned long start, end;
> unsigned long node_pfn_start, node_pfn_end;
> unsigned long node_min_pfn, node_max_pfn;
> int i;
> - unsigned long node_datasz = PFN_UP(sizeof(pg_data_t));
> int show_init = 0;
>
> /* Find the bounds of current node */
> @@ -134,24 +133,14 @@ setup_memory_node(int nid, void *kernel_end)
> /* Cute trick to make sure our local node data is on local memory */
> node_data[nid] = (pg_data_t *)(__va(node_min_pfn << PAGE_SHIFT));
> #endif
> - /* Quasi-mark the pg_data_t as in-use */
> - node_min_pfn += node_datasz;
> - if (node_min_pfn >= node_max_pfn) {
> - printk(" not enough mem to reserve NODE_DATA");
> - return;
> - }
> - NODE_DATA(nid)->bdata = &bootmem_node_data[nid];
> -
> printk(" Detected node memory: start %8lu, end %8lu\n",
> node_min_pfn, node_max_pfn);
>
> DBGDCONT(" DISCONTIG: node_data[%d] is at 0x%p\n", nid, NODE_DATA(nid));
> - DBGDCONT(" DISCONTIG: NODE_DATA(%d)->bdata is at 0x%p\n", nid, NODE_DATA(nid)->bdata);
>
> /* Find the bounds of kernel memory. */
> start_kernel_pfn = PFN_DOWN(KERNEL_START_PHYS);
> end_kernel_pfn = PFN_UP(virt_to_phys(kernel_end));
> - bootmap_start = -1;
>
> if (!nid && (node_max_pfn < end_kernel_pfn || node_min_pfn > start_kernel_pfn))
> panic("kernel loaded out of ram");
> @@ -161,89 +150,11 @@ setup_memory_node(int nid, void *kernel_end)
> has much larger alignment than 8Mb, so it's safe. */
> node_min_pfn &= ~((1UL << (MAX_ORDER-1))-1);
>
> - /* We need to know how many physically contiguous pages
> - we'll need for the bootmap. */
> - bootmap_pages = bootmem_bootmap_pages(node_max_pfn-node_min_pfn);
> -
> - /* Now find a good region where to allocate the bootmap. */
> - for_each_mem_cluster(memdesc, cluster, i) {
> - if (cluster->usage & 3)
> - continue;
> -
> - start = cluster->start_pfn;
> - end = start + cluster->numpages;
> -
> - if (start >= node_max_pfn || end <= node_min_pfn)
> - continue;
> -
> - if (end > node_max_pfn)
> - end = node_max_pfn;
> - if (start < node_min_pfn)
> - start = node_min_pfn;
> -
> - if (start < start_kernel_pfn) {
> - if (end > end_kernel_pfn
> - && end - end_kernel_pfn >= bootmap_pages) {
> - bootmap_start = end_kernel_pfn;
> - break;
> - } else if (end > start_kernel_pfn)
> - end = start_kernel_pfn;
> - } else if (start < end_kernel_pfn)
> - start = end_kernel_pfn;
> - if (end - start >= bootmap_pages) {
> - bootmap_start = start;
> - break;
> - }
> - }
> -
> - if (bootmap_start == -1)
> - panic("couldn't find a contiguous place for the bootmap");
> -
> - /* Allocate the bootmap and mark the whole MM as reserved. */
> - bootmap_size = init_bootmem_node(NODE_DATA(nid), bootmap_start,
> - node_min_pfn, node_max_pfn);
> - DBGDCONT(" bootmap_start %lu, bootmap_size %lu, bootmap_pages %lu\n",
> - bootmap_start, bootmap_size, bootmap_pages);
> + memblock_add(PFN_PHYS(node_min_pfn),
> + (node_max_pfn - node_min_pfn) << PAGE_SHIFT);
>
> - /* Mark the free regions. */
> - for_each_mem_cluster(memdesc, cluster, i) {
> - if (cluster->usage & 3)
> - continue;
> -
> - start = cluster->start_pfn;
> - end = cluster->start_pfn + cluster->numpages;
> -
> - if (start >= node_max_pfn || end <= node_min_pfn)
> - continue;
> -
> - if (end > node_max_pfn)
> - end = node_max_pfn;
> - if (start < node_min_pfn)
> - start = node_min_pfn;
> -
> - if (start < start_kernel_pfn) {
> - if (end > end_kernel_pfn) {
> - free_bootmem_node(NODE_DATA(nid), PFN_PHYS(start),
> - (PFN_PHYS(start_kernel_pfn)
> - - PFN_PHYS(start)));
> - printk(" freeing pages %ld:%ld\n",
> - start, start_kernel_pfn);
> - start = end_kernel_pfn;
> - } else if (end > start_kernel_pfn)
> - end = start_kernel_pfn;
> - } else if (start < end_kernel_pfn)
> - start = end_kernel_pfn;
> - if (start >= end)
> - continue;
> -
> - free_bootmem_node(NODE_DATA(nid), PFN_PHYS(start), PFN_PHYS(end) - PFN_PHYS(start));
> - printk(" freeing pages %ld:%ld\n", start, end);
> - }
> -
> - /* Reserve the bootmap memory. */
> - reserve_bootmem_node(NODE_DATA(nid), PFN_PHYS(bootmap_start),
> - bootmap_size, BOOTMEM_DEFAULT);
> - printk(" reserving pages %ld:%ld\n", bootmap_start, bootmap_start+PFN_UP(bootmap_size));
> + NODE_DATA(nid)->node_start_pfn = node_min_pfn;
> + NODE_DATA(nid)->node_present_pages = node_max_pfn - node_min_pfn;
>
> node_set_online(nid);
> }
> @@ -251,6 +162,7 @@ setup_memory_node(int nid, void *kernel_end)
> void __init
> setup_memory(void *kernel_end)
> {
> + unsigned long kernel_size;
> int nid;
>
> show_mem_layout();
> @@ -262,6 +174,9 @@ setup_memory(void *kernel_end)
> for (nid = 0; nid < MAX_NUMNODES; nid++)
> setup_memory_node(nid, kernel_end);
>
> + kernel_size = virt_to_phys(kernel_end) - KERNEL_START_PHYS;
> + memblock_reserve(KERNEL_START_PHYS, kernel_size);
> +
> #ifdef CONFIG_BLK_DEV_INITRD
> initrd_start = INITRD_START;
> if (initrd_start) {
> @@ -279,9 +194,8 @@ setup_memory(void *kernel_end)
> phys_to_virt(PFN_PHYS(max_low_pfn)));
> } else {
> nid = kvaddr_to_nid(initrd_start);
> - reserve_bootmem_node(NODE_DATA(nid),
> - virt_to_phys((void *)initrd_start),
> - INITRD_SIZE, BOOTMEM_DEFAULT);
> + memblock_reserve(virt_to_phys((void *)initrd_start),
> + INITRD_SIZE);
> }
> }
> #endif /* CONFIG_BLK_DEV_INITRD */
> @@ -303,9 +217,8 @@ void __init paging_init(void)
> dma_local_pfn = virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
>
> for_each_online_node(nid) {
> - bootmem_data_t *bdata = &bootmem_node_data[nid];
> - unsigned long start_pfn = bdata->node_min_pfn;
> - unsigned long end_pfn = bdata->node_low_pfn;
> + unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
> + unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_present_pages;
>
> if (dma_local_pfn >= end_pfn - start_pfn)
> zones_size[ZONE_DMA] = end_pfn - start_pfn;
> --
> 2.7.4
>

--
Sincerely yours,
Mike.