Commit ef629cc5 authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Michael Ellerman
Browse files

powerc/mm/hash: Reduce hash_mm_context size 



Allocate subpage protect related variables only if we use the feature.
This helps in reducing the hash related mm context struct by around 4K

Before the patch
sizeof(struct hash_mm_context)  = 8288

After the patch
sizeof(struct hash_mm_context) = 4160

Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 70110186

arch/powerpc/include/asm/book3s/64/mmu-hash.h

+1 −3
Original line number Diff line number Diff line
@@ -687,10 +687,8 @@ struct subpage_prot_table { 
#define SBP_L3_SHIFT		(SBP_L2_SHIFT + SBP_L2_BITS)



extern void subpage_prot_free(struct mm_struct *mm);

extern void subpage_prot_init_new_context(struct mm_struct *mm);

#else

static inline void subpage_prot_free(struct mm_struct *mm) {}

static inline void subpage_prot_init_new_context(struct mm_struct *mm) { }

#endif /* CONFIG_PPC_SUBPAGE_PROT */



/*
@@ -720,7 +718,7 @@ struct hash_mm_context { 
#endif



#ifdef CONFIG_PPC_SUBPAGE_PROT

	struct subpage_prot_table spt;

	struct subpage_prot_table *spt;

#endif /* CONFIG_PPC_SUBPAGE_PROT */

};

arch/powerpc/include/asm/book3s/64/mmu.h

+1 −1
Original line number Diff line number Diff line
@@ -206,7 +206,7 @@ static inline struct slice_mask *mm_ctx_slice_mask_16g(mm_context_t *ctx) 
#ifdef CONFIG_PPC_SUBPAGE_PROT

static inline struct subpage_prot_table *mm_ctx_subpage_prot(mm_context_t *ctx)

{

	return &ctx->hash_context->spt;

	return ctx->hash_context->spt;

}

#endif

arch/powerpc/mm/hash_utils_64.c

+3 −0
Original line number Diff line number Diff line
@@ -1150,6 +1150,9 @@ static int subpage_protection(struct mm_struct *mm, unsigned long ea) 
	u32 spp = 0;

	u32 **sbpm, *sbpp;



	if (!spt)

		return 0;



	if (ea >= spt->maxaddr)

		return 0;

	if (ea < 0x100000000UL) {

arch/powerpc/mm/mmu_context_book3s64.c

+14 −3
Original line number Diff line number Diff line
@@ -63,7 +63,8 @@ static int hash__init_new_context(struct mm_struct *mm) 
	if (index < 0)

		return index;



	mm->context.hash_context = kmalloc(sizeof(struct hash_mm_context), GFP_KERNEL);

	mm->context.hash_context = kmalloc(sizeof(struct hash_mm_context),

					   GFP_KERNEL);

	if (!mm->context.hash_context) {

		ida_free(&mmu_context_ida, index);

		return -ENOMEM;
@@ -89,10 +90,20 @@ static int hash__init_new_context(struct mm_struct *mm) 
	} else {

		/* This is fork. Copy hash_context details from current->mm */

		memcpy(mm->context.hash_context, current->mm->context.hash_context, sizeof(struct hash_mm_context));



#ifdef CONFIG_PPC_SUBPAGE_PROT

		/* inherit subpage prot detalis if we have one. */

		if (current->mm->context.hash_context->spt) {

			mm->context.hash_context->spt = kmalloc(sizeof(struct subpage_prot_table),

								GFP_KERNEL);

			if (!mm->context.hash_context->spt) {

				ida_free(&mmu_context_ida, index);

				kfree(mm->context.hash_context);

				return -ENOMEM;

			}

		}

#endif



	subpage_prot_init_new_context(mm);

	}



	pkey_mm_init(mm);

	return index;

arch/powerpc/mm/subpage-prot.c

+21 −7
Original line number Diff line number Diff line
@@ -29,6 +29,9 @@ void subpage_prot_free(struct mm_struct *mm) 
	unsigned long i, j, addr;

	u32 **p;



	if (!spt)

		return;



	for (i = 0; i < 4; ++i) {

		if (spt->low_prot[i]) {

			free_page((unsigned long)spt->low_prot[i]);
@@ -48,13 +51,7 @@ void subpage_prot_free(struct mm_struct *mm) 
		free_page((unsigned long)p);

	}

	spt->maxaddr = 0;

}



void subpage_prot_init_new_context(struct mm_struct *mm)

{

	struct subpage_prot_table *spt = mm_ctx_subpage_prot(&mm->context);



	memset(spt, 0, sizeof(*spt));

	kfree(spt);

}



static void hpte_flush_range(struct mm_struct *mm, unsigned long addr,
@@ -99,6 +96,9 @@ static void subpage_prot_clear(unsigned long addr, unsigned long len) 
	size_t nw;

	unsigned long next, limit;



	if (!spt)

		return ;



	down_write(&mm->mmap_sem);

	limit = addr + len;

	if (limit > spt->maxaddr)
@@ -218,6 +218,20 @@ SYSCALL_DEFINE3(subpage_prot, unsigned long, addr, 
		return -EFAULT;



	down_write(&mm->mmap_sem);



	if (!spt) {

		/*

		 * Allocate subpage prot table if not already done.

		 * Do this with mmap_sem held

		 */

		spt = kzalloc(sizeof(struct subpage_prot_table), GFP_KERNEL);

		if (!spt) {

			err = -ENOMEM;

			goto out;

		}

		mm->context.hash_context->spt = spt;

	}



	subpage_mark_vma_nohuge(mm, addr, len);

	for (limit = addr + len; addr < limit; addr = next) {

		next = pmd_addr_end(addr, limit);

CRA Git | Maintained and supported by SUSTech CRA and CCSE