| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <b9b7351b-ddee-64c7-e78a-00df85c56e94@linux.dev>
Date: Wed, 6 Sep 2023 15:38:16 +0800
From: Muchun Song <muchun.song@...ux.dev>
To: Mike Kravetz <mike.kravetz@...cle.com>, linux-mm@...ck.org,
linux-kernel@...r.kernel.org
Cc: Muchun Song <songmuchun@...edance.com>,
Joao Martins <joao.m.martins@...cle.com>,
Oscar Salvador <osalvador@...e.de>,
David Hildenbrand <david@...hat.com>,
Miaohe Lin <linmiaohe@...wei.com>,
David Rientjes <rientjes@...gle.com>,
Anshuman Khandual <anshuman.khandual@....com>,
Naoya Horiguchi <naoya.horiguchi@...ux.dev>,
Michal Hocko <mhocko@...e.com>,
Matthew Wilcox <willy@...radead.org>,
Xiongchun Duan <duanxiongchun@...edance.com>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH v2 08/11] hugetlb: batch freeing of vmemmap pages
On 2023/9/6 05:44, Mike Kravetz wrote:
> Now that batching of hugetlb vmemmap optimization processing is possible,
> batch the freeing of vmemmap pages. When freeing vmemmap pages for a
> hugetlb page, we add them to a list that is freed after the entire batch
> has been processed.
>
> This enhances the ability to return contiguous ranges of memory to the
> low level allocators.
>
> Signed-off-by: Mike Kravetz <mike.kravetz@...cle.com>
> ---
> mm/hugetlb_vmemmap.c | 60 ++++++++++++++++++++++++++++----------------
> 1 file changed, 38 insertions(+), 22 deletions(-)
>
> diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
> index 79de984919ef..a715712df831 100644
> --- a/mm/hugetlb_vmemmap.c
> +++ b/mm/hugetlb_vmemmap.c
> @@ -306,18 +306,21 @@ static void vmemmap_restore_pte(pte_t *pte, unsigned long addr,
> * @end: end address of the vmemmap virtual address range that we want to
> * remap.
> * @reuse: reuse address.
> + * @vmemmap_pages: list to deposit vmemmap pages to be freed. It is callers
> + * responsibility to free pages.
> *
> * Return: %0 on success, negative error code otherwise.
> */
> static int vmemmap_remap_free(unsigned long start, unsigned long end,
> - unsigned long reuse)
> + unsigned long reuse,
> + struct list_head *vmemmap_pages)
> {
> int ret;
> - LIST_HEAD(vmemmap_pages);
> + LIST_HEAD(freed_pages);
IIUC, we could reuse the parameter of @vmemmap_pages directly instead of
a temporary variable, could it be dropped?
> struct vmemmap_remap_walk walk = {
> .remap_pte = vmemmap_remap_pte,
> .reuse_addr = reuse,
> - .vmemmap_pages = &vmemmap_pages,
> + .vmemmap_pages = &freed_pages,
> };
> int nid = page_to_nid((struct page *)start);
> gfp_t gfp_mask = GFP_KERNEL | __GFP_THISNODE | __GFP_NORETRY |
> @@ -335,7 +338,7 @@ static int vmemmap_remap_free(unsigned long start, unsigned long end,
> if (walk.reuse_page) {
> copy_page(page_to_virt(walk.reuse_page),
> (void *)walk.reuse_addr);
> - list_add(&walk.reuse_page->lru, &vmemmap_pages);
> + list_add(&walk.reuse_page->lru, &freed_pages);
> }
>
> /*
> @@ -366,15 +369,14 @@ static int vmemmap_remap_free(unsigned long start, unsigned long end,
> walk = (struct vmemmap_remap_walk) {
> .remap_pte = vmemmap_restore_pte,
> .reuse_addr = reuse,
> - .vmemmap_pages = &vmemmap_pages,
> + .vmemmap_pages = &freed_pages,
> };
>
> vmemmap_remap_range(reuse, end, &walk);
> }
> mmap_read_unlock(&init_mm);
>
> - free_vmemmap_page_list(&vmemmap_pages);
> -
> + list_splice(&freed_pages, vmemmap_pages);
> return ret;
> }
>
> @@ -553,17 +555,9 @@ static bool vmemmap_should_optimize(const struct hstate *h, const struct page *h
> return true;
> }
>
> -/**
> - * hugetlb_vmemmap_optimize - optimize @head page's vmemmap pages.
> - * @h: struct hstate.
> - * @head: the head page whose vmemmap pages will be optimized.
> - *
> - * This function only tries to optimize @head's vmemmap pages and does not
> - * guarantee that the optimization will succeed after it returns. The caller
> - * can use HPageVmemmapOptimized(@head) to detect if @head's vmemmap pages
> - * have been optimized.
> - */
> -void hugetlb_vmemmap_optimize(const struct hstate *h, struct page *head)
> +static void __hugetlb_vmemmap_optimize(const struct hstate *h,
> + struct page *head,
> + struct list_head *vmemmap_pages)
> {
> unsigned long vmemmap_start = (unsigned long)head, vmemmap_end;
> unsigned long vmemmap_reuse;
> @@ -580,21 +574,43 @@ void hugetlb_vmemmap_optimize(const struct hstate *h, struct page *head)
>
> /*
> * Remap the vmemmap virtual address range [@vmemmap_start, @vmemmap_end)
> - * to the page which @vmemmap_reuse is mapped to, then free the pages
> - * which the range [@vmemmap_start, @vmemmap_end] is mapped to.
> + * to the page which @vmemmap_reuse is mapped to. Add pages previously
> + * mapping the range to vmemmap_pages list so that they can be freed by
> + * the caller.
> */
> - if (vmemmap_remap_free(vmemmap_start, vmemmap_end, vmemmap_reuse))
> + if (vmemmap_remap_free(vmemmap_start, vmemmap_end, vmemmap_reuse, vmemmap_pages))
> static_branch_dec(&hugetlb_optimize_vmemmap_key);
> else
> SetHPageVmemmapOptimized(head);
> }
>
> +/**
> + * hugetlb_vmemmap_optimize - optimize @head page's vmemmap pages.
> + * @h: struct hstate.
> + * @head: the head page whose vmemmap pages will be optimized.
> + *
> + * This function only tries to optimize @head's vmemmap pages and does not
> + * guarantee that the optimization will succeed after it returns. The caller
> + * can use HPageVmemmapOptimized(@head) to detect if @head's vmemmap pages
> + * have been optimized.
> + */
> +void hugetlb_vmemmap_optimize(const struct hstate *h, struct page *head)
> +{
> + LIST_HEAD(vmemmap_pages);
> +
> + __hugetlb_vmemmap_optimize(h, head, &vmemmap_pages);
> + free_vmemmap_page_list(&vmemmap_pages);
> +}
> +
> void hugetlb_vmemmap_optimize_folios(struct hstate *h, struct list_head *folio_list)
> {
> struct folio *folio;
> + LIST_HEAD(vmemmap_pages);
>
> list_for_each_entry(folio, folio_list, lru)
> - hugetlb_vmemmap_optimize(h, &folio->page);
> + __hugetlb_vmemmap_optimize(h, &folio->page, &vmemmap_pages);
> +
> + free_vmemmap_page_list(&vmemmap_pages);
> }
>
> static struct ctl_table hugetlb_vmemmap_sysctls[] = {
Powered by blists - more mailing lists