Commit d95936a2 authored by Kevin Brodsky's avatar Kevin Brodsky Committed by Andrew Morton
Browse files

mm: introduce ctor/dtor at PGD level 

Following on from the introduction of P4D-level ctor/dtor, let's finish
the job and introduce ctor/dtor at PGD level.  The incurred improvement in
page accounting is minimal - the main motivation is to create a single,
generic place where construction/destruction hooks can be added for all
page table pages.

This patch should cover all architectures and all configurations where
PGDs are one or more regular pages.  This excludes any configuration where
PGDs are allocated from a kmem_cache object.

Link: https://lkml.kernel.org/r/20250103184415.2744423-7-kevin.brodsky@arm.com


Signed-off-by: default avatarKevin Brodsky <kevin.brodsky@arm.com>
Acked-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
Acked-by: default avatarQi Zheng <zhengqi.arch@bytedance.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent a9b3c355

arch/m68k/include/asm/mcf_pgalloc.h

+2 −1
Original line number Diff line number Diff line
@@ -73,7 +73,7 @@ static inline void pte_free(struct mm_struct *mm, pgtable_t pgtable) 


static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)

{

	pagetable_free(virt_to_ptdesc(pgd));

	pagetable_dtor_free(virt_to_ptdesc(pgd));

}



static inline pgd_t *pgd_alloc(struct mm_struct *mm)
@@ -84,6 +84,7 @@ static inline pgd_t *pgd_alloc(struct mm_struct *mm) 


	if (!ptdesc)

		return NULL;

	pagetable_pgd_ctor(ptdesc);

	new_pgd = ptdesc_address(ptdesc);



	memcpy(new_pgd, swapper_pg_dir, PTRS_PER_PGD * sizeof(pgd_t));

arch/m68k/mm/motorola.c

+4 −2
Original line number Diff line number Diff line
@@ -169,6 +169,9 @@ void *get_pointer_table(int type) 
		case TABLE_PMD:

			pagetable_pmd_ctor(virt_to_ptdesc(page));

			break;

		case TABLE_PGD:

			pagetable_pgd_ctor(virt_to_ptdesc(page));

			break;

		}



		mmu_page_ctor(page);
@@ -207,7 +210,6 @@ int free_pointer_table(void *table, int type) 
		/* all tables in page are free, free page */

		list_del(dp);

		mmu_page_dtor((void *)page);

		if (type == TABLE_PTE || type == TABLE_PMD)

		pagetable_dtor(virt_to_ptdesc((void *)page));

		free_page (page);

		return 1;

arch/s390/include/asm/pgalloc.h

+8 −1
Original line number Diff line number Diff line
@@ -130,11 +130,18 @@ static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd) 


static inline pgd_t *pgd_alloc(struct mm_struct *mm)

{

	return (pgd_t *) crst_table_alloc(mm);

	unsigned long *table = crst_table_alloc(mm);



	if (!table)

		return NULL;

	pagetable_pgd_ctor(virt_to_ptdesc(table));



	return (pgd_t *) table;

}



static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)

{

	pagetable_dtor(virt_to_ptdesc(pgd));

	crst_table_free(mm, (unsigned long *) pgd);

}

include/asm-generic/pgalloc.h

+2 −1
Original line number Diff line number Diff line
@@ -271,6 +271,7 @@ static inline pgd_t *__pgd_alloc_noprof(struct mm_struct *mm, unsigned int order 
	if (!ptdesc)

		return NULL;



	pagetable_pgd_ctor(ptdesc);

	return ptdesc_address(ptdesc);

}

#define __pgd_alloc(...)	alloc_hooks(__pgd_alloc_noprof(__VA_ARGS__))
@@ -280,7 +281,7 @@ static inline void __pgd_free(struct mm_struct *mm, pgd_t *pgd) 
	struct ptdesc *ptdesc = virt_to_ptdesc(pgd);



	BUG_ON((unsigned long)pgd & (PAGE_SIZE-1));

	pagetable_free(ptdesc);

	pagetable_dtor_free(ptdesc);

}



#ifndef __HAVE_ARCH_PGD_FREE

include/linux/mm.h

+5 −0
Original line number Diff line number Diff line
@@ -3159,6 +3159,11 @@ static inline void pagetable_p4d_ctor(struct ptdesc *ptdesc) 
	__pagetable_ctor(ptdesc);

}



static inline void pagetable_pgd_ctor(struct ptdesc *ptdesc)

{

	__pagetable_ctor(ptdesc);

}



extern void __init pagecache_init(void);

extern void free_initmem(void);