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hugetlb: batch freeing of vmemmap pages

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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.

Link: https://lkml.kernel.org/r/20231019023113.345257-6-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Barry Song <21cnbao@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Konrad Dybcio <konradybcio@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Usama Arif <usama.arif@bytedance.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Mike Kravetz 2023-10-18 19:31:07 -07:00 committed by Andrew Morton
parent cfb8c75099
commit 91f386bf07
1 changed files with 62 additions and 32 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

94
mm/hugetlb_vmemmap.c
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@ -251,7 +251,7 @@ static void vmemmap_remap_pte(pte_t *pte, unsigned long addr,
}
entry = mk_pte(walk->reuse_page, pgprot);
list_add_tail(&page->lru, walk->vmemmap_pages);
list_add(&page->lru, walk->vmemmap_pages);
set_pte_at(&init_mm, addr, pte, entry);
}
@ -306,18 +306,20 @@ 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);
struct vmemmap_remap_walk walk = {
.remap_pte = vmemmap_remap_pte,
.reuse_addr = reuse,
.vmemmap_pages = &vmemmap_pages,
.vmemmap_pages = vmemmap_pages,
};
int nid = page_to_nid((struct page *)reuse);
gfp_t gfp_mask = GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN;
@ -334,7 +336,7 @@ 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, vmemmap_pages);
}
/*
@ -365,15 +367,13 @@ 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 = vmemmap_pages,
};
vmemmap_remap_range(reuse, end, &walk);
}
mmap_read_unlock(&init_mm);
free_vmemmap_page_list(&vmemmap_pages);
return ret;
}
@ -389,7 +389,7 @@ static int alloc_vmemmap_page_list(unsigned long start, unsigned long end,
page = alloc_pages_node(nid, gfp_mask, 0);
if (!page)
goto out;
list_add_tail(&page->lru, list);
list_add(&page->lru, list);
}
return 0;
@ -577,6 +577,39 @@ static bool vmemmap_should_optimize(const struct hstate *h, const struct page *h
return true;
}
static int __hugetlb_vmemmap_optimize(const struct hstate *h,
struct page *head,
struct list_head *vmemmap_pages)
{
int ret = 0;
unsigned long vmemmap_start = (unsigned long)head, vmemmap_end;
unsigned long vmemmap_reuse;
VM_WARN_ON_ONCE(!PageHuge(head));
if (!vmemmap_should_optimize(h, head))
return ret;
static_branch_inc(&hugetlb_optimize_vmemmap_key);
vmemmap_end = vmemmap_start + hugetlb_vmemmap_size(h);
vmemmap_reuse = vmemmap_start;
vmemmap_start += HUGETLB_VMEMMAP_RESERVE_SIZE;
/*
* Remap the vmemmap virtual address range [@vmemmap_start, @vmemmap_end)
* 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.
*/
ret = vmemmap_remap_free(vmemmap_start, vmemmap_end, vmemmap_reuse, vmemmap_pages);
if (ret)
static_branch_dec(&hugetlb_optimize_vmemmap_key);
else
SetHPageVmemmapOptimized(head);
return ret;
}
/**
* hugetlb_vmemmap_optimize - optimize @head page's vmemmap pages.
* @h: struct hstate.
@ -589,36 +622,33 @@ static bool vmemmap_should_optimize(const struct hstate *h, const struct page *h
*/
void hugetlb_vmemmap_optimize(const struct hstate *h, struct page *head)
{
unsigned long vmemmap_start = (unsigned long)head, vmemmap_end;
unsigned long vmemmap_reuse;
LIST_HEAD(vmemmap_pages);
VM_WARN_ON_ONCE(!PageHuge(head));
if (!vmemmap_should_optimize(h, head))
return;
static_branch_inc(&hugetlb_optimize_vmemmap_key);
vmemmap_end = vmemmap_start + hugetlb_vmemmap_size(h);
vmemmap_reuse = vmemmap_start;
vmemmap_start += HUGETLB_VMEMMAP_RESERVE_SIZE;
/*
* 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.
*/
if (vmemmap_remap_free(vmemmap_start, vmemmap_end, vmemmap_reuse))
static_branch_dec(&hugetlb_optimize_vmemmap_key);
else
SetHPageVmemmapOptimized(head);
__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);
list_for_each_entry(folio, folio_list, lru) {
int ret = __hugetlb_vmemmap_optimize(h, &folio->page,
&vmemmap_pages);
/*
* Pages to be freed may have been accumulated. If we
* encounter an ENOMEM, free what we have and try again.
*/
if (ret == -ENOMEM && !list_empty(&vmemmap_pages)) {
free_vmemmap_page_list(&vmemmap_pages);
INIT_LIST_HEAD(&vmemmap_pages);
__hugetlb_vmemmap_optimize(h, &folio->page, &vmemmap_pages);
}
}
free_vmemmap_page_list(&vmemmap_pages);
}
static struct ctl_table hugetlb_vmemmap_sysctls[] = {