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asm-generic: pgalloc: provide generic pmd_alloc_one() and pmd_free_one()

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For most architectures that support >2 levels of page tables,
pmd_alloc_one() is a wrapper for __get_free_pages(), sometimes with
__GFP_ZERO and sometimes followed by memset(0) instead.

More elaborate versions on arm64 and x86 account memory for the user page
tables and call to pgtable_pmd_page_ctor() as the part of PMD page
initialization.

Move the arm64 version to include/asm-generic/pgalloc.h and use the
generic version on several architectures.

The pgtable_pmd_page_ctor() is a NOP when ARCH_ENABLE_SPLIT_PMD_PTLOCK is
not enabled, so there is no functional change for most architectures
except of the addition of __GFP_ACCOUNT for allocation of user page
tables.

The pmd_free() is a wrapper for free_page() in all the cases, so no
functional change here.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Link: http://lkml.kernel.org/r/20200627143453.31835-5-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mike Rapoport 2020-08-06 23:22:39 -07:00 • committed by Linus Torvalds
parent 7278914ca1
commit 1355c31eeb
13 changed files with 55 additions and 135 deletions
Download patch file Download diff file Expand all files Collapse all files

43
include/asm-generic/pgalloc.h
View file

@ -102,6 +102,49 @@ static inline void pte_free(struct mm_struct *mm, struct page *pte_page)
__free_page(pte_page);
}
#if CONFIG_PGTABLE_LEVELS > 2
#ifndef __HAVE_ARCH_PMD_ALLOC_ONE
/**
* pmd_alloc_one - allocate a page for PMD-level page table
* @mm: the mm_struct of the current context
*
* Allocates a page and runs the pgtable_pmd_page_ctor().
* Allocations use %GFP_PGTABLE_USER in user context and
* %GFP_PGTABLE_KERNEL in kernel context.
*
* Return: pointer to the allocated memory or %NULL on error
*/
static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
{
struct page *page;
gfp_t gfp = GFP_PGTABLE_USER;
if (mm == &init_mm)
gfp = GFP_PGTABLE_KERNEL;
page = alloc_pages(gfp, 0);
if (!page)
return NULL;
if (!pgtable_pmd_page_ctor(page)) {
__free_pages(page, 0);
return NULL;
}
return (pmd_t *)page_address(page);
}
#endif
#ifndef __HAVE_ARCH_PMD_FREE
static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
{
BUG_ON((unsigned long)pmd & (PAGE_SIZE-1));
pgtable_pmd_page_dtor(virt_to_page(pmd));
free_page((unsigned long)pmd);
}
#endif
#endif /* CONFIG_PGTABLE_LEVELS > 2 */
#endif /* CONFIG_MMU */
#endif /* __ASM_GENERIC_PGALLOC_H */