Commit 9710a78a authored by Zach O'Keefe's avatar Zach O'Keefe Committed by Andrew Morton
Browse files

mm/khugepaged: dedup and simplify hugepage alloc and charging 

The following code is duplicated in collapse_huge_page() and
collapse_file():

        gfp = alloc_hugepage_khugepaged_gfpmask() | __GFP_THISNODE;

	new_page = khugepaged_alloc_page(hpage, gfp, node);
        if (!new_page) {
                result = SCAN_ALLOC_HUGE_PAGE_FAIL;
                goto out;
        }

        if (unlikely(mem_cgroup_charge(page_folio(new_page), mm, gfp))) {
                result = SCAN_CGROUP_CHARGE_FAIL;
                goto out;
        }
        count_memcg_page_event(new_page, THP_COLLAPSE_ALLOC);

Also, "node" is passed as an argument to both collapse_huge_page() and
collapse_file() and obtained the same way, via
khugepaged_find_target_node().

Move all this into a new helper, alloc_charge_hpage(), and remove the
duplicate code from collapse_huge_page() and collapse_file().  Also,
simplify khugepaged_alloc_page() by returning a bool indicating allocation
success instead of a copy of the allocated struct page *.

Link: https://lkml.kernel.org/r/20220706235936.2197195-5-zokeefe@google.com


Signed-off-by: default avatarZach O'Keefe <zokeefe@google.com>
Suggested-by: default avatarPeter Xu <peterx@redhat.com>
Acked-by: default avatarDavid Rientjes <rientjes@google.com>
Reviewed-by: default avatarYang Shi <shy828301@gmail.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Chris Kennelly <ckennelly@google.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Cc: Rongwei Wang <rongwei.wang@linux.alibaba.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Souptick Joarder (HPE)" <jrdr.linux@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 34d6b470

mm/khugepaged.c

+35 −43
Original line number Diff line number Diff line
@@ -813,19 +813,18 @@ static int khugepaged_find_target_node(struct collapse_control *cc) 
}

#endif



static struct page *

khugepaged_alloc_page(struct page **hpage, gfp_t gfp, int node)

static bool khugepaged_alloc_page(struct page **hpage, gfp_t gfp, int node)

{

	*hpage = __alloc_pages_node(node, gfp, HPAGE_PMD_ORDER);

	if (unlikely(!*hpage)) {

		count_vm_event(THP_COLLAPSE_ALLOC_FAILED);

		*hpage = ERR_PTR(-ENOMEM);

		return NULL;

		return false;

	}



	prep_transhuge_page(*hpage);

	count_vm_event(THP_COLLAPSE_ALLOC);

	return *hpage;

	return true;

}



/*
@@ -923,10 +922,24 @@ static bool __collapse_huge_page_swapin(struct mm_struct *mm, 
	return true;

}



static void collapse_huge_page(struct mm_struct *mm,

				   unsigned long address,

				   struct page **hpage,

				   int node, int referenced, int unmapped)

static int alloc_charge_hpage(struct page **hpage, struct mm_struct *mm,

			      struct collapse_control *cc)

{

	/* Only allocate from the target node */

	gfp_t gfp = alloc_hugepage_khugepaged_gfpmask() | __GFP_THISNODE;

	int node = khugepaged_find_target_node(cc);



	if (!khugepaged_alloc_page(hpage, gfp, node))

		return SCAN_ALLOC_HUGE_PAGE_FAIL;

	if (unlikely(mem_cgroup_charge(page_folio(*hpage), mm, gfp)))

		return SCAN_CGROUP_CHARGE_FAIL;

	count_memcg_page_event(*hpage, THP_COLLAPSE_ALLOC);

	return SCAN_SUCCEED;

}



static void collapse_huge_page(struct mm_struct *mm, unsigned long address,

			       struct page **hpage, int referenced,

			       int unmapped, struct collapse_control *cc)

{

	LIST_HEAD(compound_pagelist);

	pmd_t *pmd, _pmd;
@@ -937,13 +950,9 @@ static void collapse_huge_page(struct mm_struct *mm, 
	int isolated = 0, result = 0;

	struct vm_area_struct *vma;

	struct mmu_notifier_range range;

	gfp_t gfp;



	VM_BUG_ON(address & ~HPAGE_PMD_MASK);



	/* Only allocate from the target node */

	gfp = alloc_hugepage_khugepaged_gfpmask() | __GFP_THISNODE;



	/*

	 * Before allocating the hugepage, release the mmap_lock read lock.

	 * The allocation can take potentially a long time if it involves
@@ -951,17 +960,12 @@ static void collapse_huge_page(struct mm_struct *mm, 
	 * that. We will recheck the vma after taking it again in write mode.

	 */

	mmap_read_unlock(mm);

	new_page = khugepaged_alloc_page(hpage, gfp, node);

	if (!new_page) {

		result = SCAN_ALLOC_HUGE_PAGE_FAIL;

		goto out_nolock;

	}



	if (unlikely(mem_cgroup_charge(page_folio(new_page), mm, gfp))) {

		result = SCAN_CGROUP_CHARGE_FAIL;

	result = alloc_charge_hpage(hpage, mm, cc);

	if (result != SCAN_SUCCEED)

		goto out_nolock;

	}

	count_memcg_page_event(new_page, THP_COLLAPSE_ALLOC);



	new_page = *hpage;



	mmap_read_lock(mm);

	result = hugepage_vma_revalidate(mm, address, &vma);
@@ -1235,10 +1239,9 @@ static int khugepaged_scan_pmd(struct mm_struct *mm, struct vm_area_struct *vma, 
out_unmap:

	pte_unmap_unlock(pte, ptl);

	if (ret) {

		node = khugepaged_find_target_node(cc);

		/* collapse_huge_page will return with the mmap_lock released */

		collapse_huge_page(mm, address, hpage, node,

				referenced, unmapped);

		collapse_huge_page(mm, address, hpage, referenced, unmapped,

				   cc);

	}

out:

	trace_mm_khugepaged_scan_pmd(mm, page, writable, referenced,
@@ -1506,7 +1509,7 @@ static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff) 
 * @file: file that collapse on

 * @start: collapse start address

 * @hpage: new allocated huge page for collapse

 * @node: appointed node the new huge page allocate from

 * @cc: collapse context and scratchpad

 *

 * Basic scheme is simple, details are more complex:

 *  - allocate and lock a new huge page;
@@ -1523,12 +1526,11 @@ static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff) 
 *    + restore gaps in the page cache;

 *    + unlock and free huge page;

 */

static void collapse_file(struct mm_struct *mm,

		struct file *file, pgoff_t start,

		struct page **hpage, int node)

static void collapse_file(struct mm_struct *mm, struct file *file,

			  pgoff_t start, struct page **hpage,

			  struct collapse_control *cc)

{

	struct address_space *mapping = file->f_mapping;

	gfp_t gfp;

	struct page *new_page;

	pgoff_t index, end = start + HPAGE_PMD_NR;

	LIST_HEAD(pagelist);
@@ -1540,20 +1542,11 @@ static void collapse_file(struct mm_struct *mm, 
	VM_BUG_ON(!IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) && !is_shmem);

	VM_BUG_ON(start & (HPAGE_PMD_NR - 1));



	/* Only allocate from the target node */

	gfp = alloc_hugepage_khugepaged_gfpmask() | __GFP_THISNODE;



	new_page = khugepaged_alloc_page(hpage, gfp, node);

	if (!new_page) {

		result = SCAN_ALLOC_HUGE_PAGE_FAIL;

	result = alloc_charge_hpage(hpage, mm, cc);

	if (result != SCAN_SUCCEED)

		goto out;

	}



	if (unlikely(mem_cgroup_charge(page_folio(new_page), mm, gfp))) {

		result = SCAN_CGROUP_CHARGE_FAIL;

		goto out;

	}

	count_memcg_page_event(new_page, THP_COLLAPSE_ALLOC);

	new_page = *hpage;



	/*

	 * Ensure we have slots for all the pages in the range.  This is
@@ -1965,8 +1958,7 @@ static void khugepaged_scan_file(struct mm_struct *mm, struct file *file, 
			result = SCAN_EXCEED_NONE_PTE;

			count_vm_event(THP_SCAN_EXCEED_NONE_PTE);

		} else {

			node = khugepaged_find_target_node(cc);

			collapse_file(mm, file, start, hpage, node);

			collapse_file(mm, file, start, hpage, cc);

		}

	}