Re: [PATCH v7] hugetlbfs: Extend the definition of hugepages parameter to support node allocation

Mike Kravetz
2021-10-01T22:34:44Z

On 9/27/21 3:41 AM, Zhenguo Yao wrote:
> We can specify the number of hugepages to allocate at boot. But the
> hugepages is balanced in all nodes at present. In some scenarios,
> we only need hugepages in one node. For example: DPDK needs hugepages
> which are in the same node as NIC. if DPDK needs four hugepages of 1G
> size in node1 and system has 16 numa nodes. We must reserve 64 hugepages
> in kernel cmdline. But, only four hugepages are used. The others should
> be free after boot. If the system memory is low(for example: 64G), it will
> be an impossible task. So, Extending hugepages parameter to support
> specifying hugepages at a specific node.
> For example add following parameter:
>
> hugepagesz=1G hugepages=0:1,1:3
>
> It will allocate 1 hugepage in node0 and 3 hugepages in node1.
>
> Signed-off-by: Zhenguo Yao <yaozhenguo1@gmail.com>

Thanks for your continued efforts! And, thank you Mike R. for your
input.

Just a few very minor comments below. Everything else looks good.
With suggested updates,

Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>

> ---
> v6->v7 changes:
> - replace nodes_weight(node_states[N_MEMORY] with nr_online_nodes.
> v5->v6 changes:
> - Remove v5 codes: using return value to disable node specific alloc.
> - Add node_specific_alloc_support weak function to disable node
> specific alloc when arch can't support it.
> - Remove useless variable addr in alloc_bootmem_huge_page.
> - Add powerpc version of node_specific_alloc_support when
> CONFIG_PPC_BOOK3S_64 is defined.
> v4->v5 changes:
> - remove BUG_ON in __alloc_bootmem_huge_page.
> - add nid parameter in __alloc_bootmem_huge_page to support
> called in both specific node alloc and normal alloc.
> - do normal alloc if architecture can't support node specific alloc.
> - return -1 in powerpc version of alloc_bootmem_huge_page when
> nid is not NUMA_NO_NODE.
> v3->v4 changes:
> - fix wrong behavior for parameter:
> hugepages=0:1,1:3 default_hugepagesz=1G
> - make the change of documentation more reasonable.
> v2->v3 changes:
> - Skip gigantic hugepages allocation if hugetlb_cma is enabled.
> - Fix wrong behavior for parameter:
> hugepagesz=2M hugepages=2 hugepages=5.
> - Update hugetlbpage.rst.
> - Fix side effects which v2 brings in.
> - add cond_resched in hugetlb_hstate_alloc_pages_onenode.
> v1->v2 changes:
> - add checking for max node to avoid array out of bounds.
> - fix wrong max_huge_pages after failed allocation.
> - fix wrong behavior when parsing parameter: hugepages=0:1,2,3:4.
> - return 0 when parsing invalid parameter in hugepages_setup
> ---
> .../admin-guide/kernel-parameters.txt | 8 +-
> Documentation/admin-guide/mm/hugetlbpage.rst | 12 +-
> arch/powerpc/mm/hugetlbpage.c | 9 +-
> include/linux/hugetlb.h | 6 +-
> mm/hugetlb.c | 153 +++++++++++++++---
> 5 files changed, 157 insertions(+), 31 deletions(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 91ba391f9b32..9b3d8791586d 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -1599,9 +1599,11 @@
> the number of pages of hugepagesz to be allocated.
> If this is the first HugeTLB parameter on the command
> line, it specifies the number of pages to allocate for
> - the default huge page size. See also
> - Documentation/admin-guide/mm/hugetlbpage.rst.
> - Format: <integer>
> + the default huge page size. If using node format, the
> + number of pages to allocate per-node can be specified.
> + See also Documentation/admin-guide/mm/hugetlbpage.rst.
> + Format: <integer> or (node format)
> + <node>:<integer>[,<node>:<integer>]
>
> hugepagesz=
> [HW] The size of the HugeTLB pages. This is used in
> diff --git a/Documentation/admin-guide/mm/hugetlbpage.rst b/Documentation/admin-guide/mm/hugetlbpage.rst
> index 8abaeb144e44..d70828c07658 100644
> --- a/Documentation/admin-guide/mm/hugetlbpage.rst
> +++ b/Documentation/admin-guide/mm/hugetlbpage.rst
> @@ -128,7 +128,9 @@ hugepages
> implicitly specifies the number of huge pages of default size to
> allocate. If the number of huge pages of default size is implicitly
> specified, it can not be overwritten by a hugepagesz,hugepages
> - parameter pair for the default size.
> + parameter pair for the default size. This parameter also has a
> + node format. The node format specifies the number of huge pages
> + to allocate on specific nodes.
>
> For example, on an architecture with 2M default huge page size::
>
> @@ -138,6 +140,14 @@ hugepages
> indicating that the hugepages=512 parameter is ignored. If a hugepages
> parameter is preceded by an invalid hugepagesz parameter, it will
> be ignored.
> +
> + Node format example::
> +
> + hugepagesz=2M hugepages=0:1,1:2
> +
> + It will allocate 1 2M hugepage on node0 and 2 2M hugepages on node1.
> + If the node number is invalid, the parameter will be ignored.
> +
> default_hugepagesz
> Specify the default huge page size. This parameter can
> only be specified once on the command line. default_hugepagesz can
> diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
> index 9a75ba078e1b..dd40ce6e7565 100644
> --- a/arch/powerpc/mm/hugetlbpage.c
> +++ b/arch/powerpc/mm/hugetlbpage.c
> @@ -229,17 +229,22 @@ static int __init pseries_alloc_bootmem_huge_page(struct hstate *hstate)
> m->hstate = hstate;
> return 1;
> }
> +
> +bool __init node_specific_alloc_support(void)
> +{
> + return false;
> +}
> #endif
>
>
> -int __init alloc_bootmem_huge_page(struct hstate *h)
> +int __init alloc_bootmem_huge_page(struct hstate *h, int nid)
> {
>
> #ifdef CONFIG_PPC_BOOK3S_64
> if (firmware_has_feature(FW_FEATURE_LPAR) && !radix_enabled())
> return pseries_alloc_bootmem_huge_page(h);
> #endif
> - return __alloc_bootmem_huge_page(h);
> + return __alloc_bootmem_huge_page(h, nid);
> }
>
> #ifndef CONFIG_PPC_BOOK3S_64
> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> index 1faebe1cd0ed..3504e407567c 100644
> --- a/include/linux/hugetlb.h
> +++ b/include/linux/hugetlb.h
> @@ -605,6 +605,7 @@ struct hstate {
> unsigned long nr_overcommit_huge_pages;
> struct list_head hugepage_activelist;
> struct list_head hugepage_freelists[MAX_NUMNODES];
> + unsigned int max_huge_pages_node[MAX_NUMNODES];
> unsigned int nr_huge_pages_node[MAX_NUMNODES];
> unsigned int free_huge_pages_node[MAX_NUMNODES];
> unsigned int surplus_huge_pages_node[MAX_NUMNODES];
> @@ -637,8 +638,9 @@ void restore_reserve_on_error(struct hstate *h, struct vm_area_struct *vma,
> unsigned long address, struct page *page);
>
> /* arch callback */
> -int __init __alloc_bootmem_huge_page(struct hstate *h);
> -int __init alloc_bootmem_huge_page(struct hstate *h);
> +int __init __alloc_bootmem_huge_page(struct hstate *h, int nid);
> +int __init alloc_bootmem_huge_page(struct hstate *h, int nid);
> +bool __init node_specific_alloc_support(void);

Agree with Mike R. that hugetlb should be in the name.

>
> void __init hugetlb_add_hstate(unsigned order);
> bool __init arch_hugetlb_valid_size(unsigned long size);
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 95dc7b83381f..ca00676a1bdd 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -66,6 +66,7 @@ static struct hstate * __initdata parsed_hstate;
> static unsigned long __initdata default_hstate_max_huge_pages;
> static bool __initdata parsed_valid_hugepagesz = true;
> static bool __initdata parsed_default_hugepagesz;
> +static unsigned int default_hugepages_in_node[MAX_NUMNODES] __initdata;
>
> /*
> * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
> @@ -2868,33 +2869,41 @@ struct page *alloc_huge_page(struct vm_area_struct *vma,
> return ERR_PTR(-ENOSPC);
> }
>
> -int alloc_bootmem_huge_page(struct hstate *h)
> +int alloc_bootmem_huge_page(struct hstate *h, int nid)
> __attribute__ ((weak, alias("__alloc_bootmem_huge_page")));
> -int __alloc_bootmem_huge_page(struct hstate *h)
> +int __alloc_bootmem_huge_page(struct hstate *h, int nid)
> {
> struct huge_bootmem_page *m;
> int nr_nodes, node;
>
> + if (nid >= nr_online_nodes)
> + return 0;
> + /* do node specific alloc */
> + if (nid != NUMA_NO_NODE) {
> + m = memblock_alloc_try_nid_raw(huge_page_size(h), huge_page_size(h),
> + 0, MEMBLOCK_ALLOC_ACCESSIBLE, nid);
> + if (m)
> + goto found;
> + else
> + return 0;
> + }
> + /* do all node balanced alloc */

I'm sure you saw Smatch does not like this comment. Perhaps,
/* allocate from next node when distributing huge pages */

> for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
> - void *addr;
> -
> - addr = memblock_alloc_try_nid_raw(
> + m = memblock_alloc_try_nid_raw(
> huge_page_size(h), huge_page_size(h),
> 0, MEMBLOCK_ALLOC_ACCESSIBLE, node);
> - if (addr) {
> - /*
> - * Use the beginning of the huge page to store the
> - * huge_bootmem_page struct (until gather_bootmem
> - * puts them into the mem_map).
> - */
> - m = addr;
> + /*
> + * Use the beginning of the huge page to store the
> + * huge_bootmem_page struct (until gather_bootmem
> + * puts them into the mem_map).
> + */
> + if (m)
> goto found;
> - }
> + else
> + return 0;
> }
> - return 0;
>
> found:
> - BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
> /* Put them into a private list first because mem_map is not up yet */
> INIT_LIST_HEAD(&m->list);
> list_add(&m->list, &huge_boot_pages);
> @@ -2934,12 +2943,61 @@ static void __init gather_bootmem_prealloc(void)
> cond_resched();
> }
> }
> +static void __init hugetlb_hstate_alloc_pages_onenode(struct hstate *h, int nid)
> +{
> + unsigned long i;
> + char buf[32];
> +
> + for (i = 0; i < h->max_huge_pages_node[nid]; ++i) {
> + if (hstate_is_gigantic(h)) {
> + if (!alloc_bootmem_huge_page(h, nid))
> + break;
> + } else {
> + struct page *page;
> + gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
> +
> + page = alloc_fresh_huge_page(h, gfp_mask, nid,
> + &node_states[N_MEMORY], NULL);
> + if (!page)
> + break;
> + put_page(page); /* free it into the hugepage allocator */
> + }
> + cond_resched();
> + }
> + if (i == h->max_huge_pages_node[nid])
> + return;
> +
> + string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
> + pr_warn("HugeTLB: allocating %u of page size %s failed node%d. Only allocated %lu hugepages.\n",
> + h->max_huge_pages_node[nid], buf, nid, i);
> + h->max_huge_pages -= (h->max_huge_pages_node[nid] - i);
> + h->max_huge_pages_node[nid] = i;
> +}
>
> static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
> {
> unsigned long i;
> nodemask_t *node_alloc_noretry;
> + bool node_specific_alloc = false;
> +
> + /* skip gigantic hugepages allocation if hugetlb_cma enabled */
> + if (hstate_is_gigantic(h) && hugetlb_cma_size) {
> + pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n");
> + return;
> + }
> +
> + /* do node specific alloc */
> + for (i = 0; i < nr_online_nodes; i++) {
> + if (h->max_huge_pages_node[i] > 0) {
> + hugetlb_hstate_alloc_pages_onenode(h, i);
> + node_specific_alloc = true;
> + }
> + }
>
> + if (node_specific_alloc)
> + return;
> +
> + /* bellow will do all node balanced alloc */

below

> if (!hstate_is_gigantic(h)) {
> /*
> * Bit mask controlling how hard we retry per-node allocations.
> @@ -2960,11 +3018,7 @@ static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
>
> for (i = 0; i < h->max_huge_pages; ++i) {
> if (hstate_is_gigantic(h)) {
> - if (hugetlb_cma_size) {
> - pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n");
> - goto free;
> - }
> - if (!alloc_bootmem_huge_page(h))
> + if (!alloc_bootmem_huge_page(h, NUMA_NO_NODE))
> break;
> } else if (!alloc_pool_huge_page(h,
> &node_states[N_MEMORY],
> @@ -2980,7 +3034,6 @@ static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
> h->max_huge_pages, buf, i);
> h->max_huge_pages = i;
> }
> -free:
> kfree(node_alloc_noretry);
> }
>
> @@ -3671,6 +3724,11 @@ static int __init hugetlb_init(void)

> default_hstate.max_huge_pages =
> default_hstate_max_huge_pages;
> +
> + for (i = 0; i < nr_online_nodes; i++)
> + if (default_hugepages_in_node[i] > 0)
> + default_hstate.max_huge_pages_node[i] =
> + default_hugepages_in_node[i];

Very minor nit. Not necessary to change.
The 'if (default_hugepages_in_node[i] > 0)' is not really needed. I am
not sure if any potential speed up by the check would be noticable. You
need to 'read' every value in the array.

> }
> }
>
> @@ -3731,6 +3789,10 @@ void __init hugetlb_add_hstate(unsigned int order)
> parsed_hstate = h;
> }
>
> +bool __init __weak node_specific_alloc_support(void)
> +{
> + return true;
> +}
> /*
> * hugepages command line processing
> * hugepages normally follows a valid hugepagsz or default_hugepagsz
> @@ -3742,6 +3804,10 @@ static int __init hugepages_setup(char *s)
> {
> unsigned long *mhp;
> static unsigned long *last_mhp;
> + int node = NUMA_NO_NODE;
> + int count;
> + unsigned long tmp;
> + char *p = s;
>
> if (!parsed_valid_hugepagesz) {
> pr_warn("HugeTLB: hugepages=%s does not follow a valid hugepagesz, ignoring\n", s);
> @@ -3765,8 +3831,40 @@ static int __init hugepages_setup(char *s)
> return 0;
> }
>
> - if (sscanf(s, "%lu", mhp) <= 0)
> - *mhp = 0;
> + while (*p) {
> + count = 0;
> + if (sscanf(p, "%lu%n", &tmp, &count) != 1)
> + goto invalid;
> + /* Parameter is node format */
> + if (p[count] == ':') {
> + if (!node_specific_alloc_support()) {
> + pr_warn("HugeTLB: architecture can't support node specific alloc, ignoring!\n");
> + return 0;
> + }
> + node = tmp;
> + p += count + 1;
> + if (node < 0 || node >= nr_online_nodes)
> + goto invalid;
> + /* Parse hugepages */
> + if (sscanf(p, "%lu%n", &tmp, &count) != 1)
> + goto invalid;
> + if (!hugetlb_max_hstate)
> + default_hugepages_in_node[node] = tmp;
> + else
> + parsed_hstate->max_huge_pages_node[node] = tmp;
> + *mhp += tmp;
> + /* Go to parse next node*/
> + if (p[count] == ',')
> + p += count + 1;
> + else
> + break;
> + } else {
> + if (p != s)
> + goto invalid;
> + *mhp = tmp;
> + break;
> + }
> + }
>
> /*
> * Global state is always initialized later in hugetlb_init.
> @@ -3779,6 +3877,10 @@ static int __init hugepages_setup(char *s)
> last_mhp = mhp;
>
> return 1;
> +
> +invalid:
> + pr_warn("HugeTLB: Invalid hugepages parameter %s\n", p);
> + return 0;
> }
> __setup("hugepages=", hugepages_setup);
>
> @@ -3840,6 +3942,7 @@ __setup("hugepagesz=", hugepagesz_setup);
> static int __init default_hugepagesz_setup(char *s)
> {
> unsigned long size;
> + int i;
>
> parsed_valid_hugepagesz = false;
> if (parsed_default_hugepagesz) {
> @@ -3868,6 +3971,10 @@ static int __init default_hugepagesz_setup(char *s)
> */
> if (default_hstate_max_huge_pages) {
> default_hstate.max_huge_pages = default_hstate_max_huge_pages;
> + for (i = 0; i < nr_online_nodes; i++)
> + if (default_hugepages_in_node[i] > 0)
> + default_hstate.max_huge_pages_node[i] =
> + default_hugepages_in_node[i];

Same minor nit as in hugetlb_init.

> if (hstate_is_gigantic(&default_hstate))
> hugetlb_hstate_alloc_pages(&default_hstate);
> default_hstate_max_huge_pages = 0;
>

--
Mike Kravetz