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mm/memory: Move mmu_gather and TLB invalidation code into its own file 

In preparation for maintaining the mmu_gather code as its own entity,
move the implementation out of memory.c and into its own file.

Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Peter Zijlstra 2018-09-03 15:07:36 +01:00 committed by Will Deacon
parent a6d60245d6
commit 196d9d8bb7
4 changed files with 265 additions and 252 deletions
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1
include/asm-generic/tlb.h
View File

@ -138,6 +138,7 @@ void arch_tlb_gather_mmu(struct mmu_gather *tlb,
void tlb_flush_mmu(struct mmu_gather *tlb);
void arch_tlb_finish_mmu(struct mmu_gather *tlb,
unsigned long start, unsigned long end, bool force);
void tlb_flush_mmu_free(struct mmu_gather *tlb);
extern bool __tlb_remove_page_size(struct mmu_gather *tlb, struct page *page,
int page_size);

6
mm/Makefile
View File

@ -23,9 +23,9 @@ KCOV_INSTRUMENT_vmstat.o := n
mmu-y := nommu.o
mmu-$(CONFIG_MMU) := gup.o highmem.o memory.o mincore.o \
mlock.o mmap.o mprotect.o mremap.o msync.o \
page_vma_mapped.o pagewalk.o pgtable-generic.o \
rmap.o vmalloc.o
mlock.o mmap.o mmu_gather.o mprotect.o mremap.o \
msync.o page_vma_mapped.o pagewalk.o \
pgtable-generic.o rmap.o vmalloc.o
ifdef CONFIG_CROSS_MEMORY_ATTACH

249
mm/memory.c
View File

@ -186,255 +186,6 @@ static void check_sync_rss_stat(struct task_struct *task)
#endif /* SPLIT_RSS_COUNTING */
#ifdef HAVE_GENERIC_MMU_GATHER
static bool tlb_next_batch(struct mmu_gather *tlb)
{
struct mmu_gather_batch *batch;
batch = tlb->active;
if (batch->next) {
tlb->active = batch->next;
return true;
}
if (tlb->batch_count == MAX_GATHER_BATCH_COUNT)
return false;
batch = (void *)__get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0);
if (!batch)
return false;
tlb->batch_count++;
batch->next = NULL;
batch->nr = 0;
batch->max = MAX_GATHER_BATCH;
tlb->active->next = batch;
tlb->active = batch;
return true;
}
void arch_tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
unsigned long start, unsigned long end)
{
tlb->mm = mm;
/* Is it from 0 to ~0? */
tlb->fullmm = !(start | (end+1));
tlb->need_flush_all = 0;
tlb->local.next = NULL;
tlb->local.nr = 0;
tlb->local.max = ARRAY_SIZE(tlb->__pages);
tlb->active = &tlb->local;
tlb->batch_count = 0;
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
tlb->batch = NULL;
#endif
tlb->page_size = 0;
__tlb_reset_range(tlb);
}
static void tlb_flush_mmu_free(struct mmu_gather *tlb)
{
struct mmu_gather_batch *batch;
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
tlb_table_flush(tlb);
#endif
for (batch = &tlb->local; batch && batch->nr; batch = batch->next) {
free_pages_and_swap_cache(batch->pages, batch->nr);
batch->nr = 0;
}
tlb->active = &tlb->local;
}
void tlb_flush_mmu(struct mmu_gather *tlb)
{
tlb_flush_mmu_tlbonly(tlb);
tlb_flush_mmu_free(tlb);
}
/* tlb_finish_mmu
* Called at the end of the shootdown operation to free up any resources
* that were required.
*/
void arch_tlb_finish_mmu(struct mmu_gather *tlb,
unsigned long start, unsigned long end, bool force)
{
struct mmu_gather_batch *batch, *next;
if (force) {
__tlb_reset_range(tlb);
__tlb_adjust_range(tlb, start, end - start);
}
tlb_flush_mmu(tlb);
/* keep the page table cache within bounds */
check_pgt_cache();
for (batch = tlb->local.next; batch; batch = next) {
next = batch->next;
free_pages((unsigned long)batch, 0);
}
tlb->local.next = NULL;
}
/* __tlb_remove_page
* Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while
* handling the additional races in SMP caused by other CPUs caching valid
* mappings in their TLBs. Returns the number of free page slots left.
* When out of page slots we must call tlb_flush_mmu().
*returns true if the caller should flush.
*/
bool __tlb_remove_page_size(struct mmu_gather *tlb, struct page *page, int page_size)
{
struct mmu_gather_batch *batch;
VM_BUG_ON(!tlb->end);
VM_WARN_ON(tlb->page_size != page_size);
batch = tlb->active;
/*
* Add the page and check if we are full. If so
* force a flush.
*/
batch->pages[batch->nr++] = page;
if (batch->nr == batch->max) {
if (!tlb_next_batch(tlb))
return true;
batch = tlb->active;
}
VM_BUG_ON_PAGE(batch->nr > batch->max, page);
return false;
}
#endif /* HAVE_GENERIC_MMU_GATHER */
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
/*
* See the comment near struct mmu_table_batch.
*/
/*
* If we want tlb_remove_table() to imply TLB invalidates.
*/
static inline void tlb_table_invalidate(struct mmu_gather *tlb)
{
#ifdef CONFIG_HAVE_RCU_TABLE_INVALIDATE
/*
* Invalidate page-table caches used by hardware walkers. Then we still
* need to RCU-sched wait while freeing the pages because software
* walkers can still be in-flight.
*/
tlb_flush_mmu_tlbonly(tlb);
#endif
}
static void tlb_remove_table_smp_sync(void *arg)
{
/* Simply deliver the interrupt */
}
static void tlb_remove_table_one(void *table)
{
/*
* This isn't an RCU grace period and hence the page-tables cannot be
* assumed to be actually RCU-freed.
*
* It is however sufficient for software page-table walkers that rely on
* IRQ disabling. See the comment near struct mmu_table_batch.
*/
smp_call_function(tlb_remove_table_smp_sync, NULL, 1);
__tlb_remove_table(table);
}
static void tlb_remove_table_rcu(struct rcu_head *head)
{
struct mmu_table_batch *batch;
int i;
batch = container_of(head, struct mmu_table_batch, rcu);
for (i = 0; i < batch->nr; i++)
__tlb_remove_table(batch->tables[i]);
free_page((unsigned long)batch);
}
void tlb_table_flush(struct mmu_gather *tlb)
{
struct mmu_table_batch **batch = &tlb->batch;
if (*batch) {
tlb_table_invalidate(tlb);
call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu);
*batch = NULL;
}
}
void tlb_remove_table(struct mmu_gather *tlb, void *table)
{
struct mmu_table_batch **batch = &tlb->batch;
if (*batch == NULL) {
*batch = (struct mmu_table_batch *)__get_free_page(GFP_NOWAIT | __GFP_NOWARN);
if (*batch == NULL) {
tlb_table_invalidate(tlb);
tlb_remove_table_one(table);
return;
}
(*batch)->nr = 0;
}
(*batch)->tables[(*batch)->nr++] = table;
if ((*batch)->nr == MAX_TABLE_BATCH)
tlb_table_flush(tlb);
}
#endif /* CONFIG_HAVE_RCU_TABLE_FREE */
/**
* tlb_gather_mmu - initialize an mmu_gather structure for page-table tear-down
* @tlb: the mmu_gather structure to initialize
* @mm: the mm_struct of the target address space
* @start: start of the region that will be removed from the page-table
* @end: end of the region that will be removed from the page-table
*
* Called to initialize an (on-stack) mmu_gather structure for page-table
* tear-down from @mm. The @start and @end are set to 0 and -1
* respectively when @mm is without users and we're going to destroy
* the full address space (exit/execve).
*/
void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
unsigned long start, unsigned long end)
{
arch_tlb_gather_mmu(tlb, mm, start, end);
inc_tlb_flush_pending(tlb->mm);
}
void tlb_finish_mmu(struct mmu_gather *tlb,
unsigned long start, unsigned long end)
{
/*
* If there are parallel threads are doing PTE changes on same range
* under non-exclusive lock(e.g., mmap_sem read-side) but defer TLB
* flush by batching, a thread has stable TLB entry can fail to flush
* the TLB by observing pte_none|!pte_dirty, for example so flush TLB
* forcefully if we detect parallel PTE batching threads.
*/
bool force = mm_tlb_flush_nested(tlb->mm);
arch_tlb_finish_mmu(tlb, start, end, force);
dec_tlb_flush_pending(tlb->mm);
}
/*
* Note: this doesn't free the actual pages themselves. That
* has been handled earlier when unmapping all the memory regions.

261
mm/mmu_gather.c Normal file
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@ -0,0 +1,261 @@
#include <linux/gfp.h>
#include <linux/highmem.h>
#include <linux/kernel.h>
#include <linux/mmdebug.h>
#include <linux/mm_types.h>
#include <linux/pagemap.h>
#include <linux/rcupdate.h>
#include <linux/smp.h>
#include <linux/swap.h>
#include <asm/pgalloc.h>
#include <asm/tlb.h>
#ifdef HAVE_GENERIC_MMU_GATHER
static bool tlb_next_batch(struct mmu_gather *tlb)
{
struct mmu_gather_batch *batch;
batch = tlb->active;
if (batch->next) {
tlb->active = batch->next;
return true;
}
if (tlb->batch_count == MAX_GATHER_BATCH_COUNT)
return false;
batch = (void *)__get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0);
if (!batch)
return false;
tlb->batch_count++;
batch->next = NULL;
batch->nr = 0;
batch->max = MAX_GATHER_BATCH;
tlb->active->next = batch;
tlb->active = batch;
return true;
}
void arch_tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
unsigned long start, unsigned long end)
{
tlb->mm = mm;
/* Is it from 0 to ~0? */
tlb->fullmm = !(start | (end+1));
tlb->need_flush_all = 0;
tlb->local.next = NULL;
tlb->local.nr = 0;
tlb->local.max = ARRAY_SIZE(tlb->__pages);
tlb->active = &tlb->local;
tlb->batch_count = 0;
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
tlb->batch = NULL;
#endif
tlb->page_size = 0;
__tlb_reset_range(tlb);
}
void tlb_flush_mmu_free(struct mmu_gather *tlb)
{
struct mmu_gather_batch *batch;
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
tlb_table_flush(tlb);
#endif
for (batch = &tlb->local; batch && batch->nr; batch = batch->next) {
free_pages_and_swap_cache(batch->pages, batch->nr);
batch->nr = 0;
}
tlb->active = &tlb->local;
}
void tlb_flush_mmu(struct mmu_gather *tlb)
{
tlb_flush_mmu_tlbonly(tlb);
tlb_flush_mmu_free(tlb);
}
/* tlb_finish_mmu
* Called at the end of the shootdown operation to free up any resources
* that were required.
*/
void arch_tlb_finish_mmu(struct mmu_gather *tlb,
unsigned long start, unsigned long end, bool force)
{
struct mmu_gather_batch *batch, *next;
if (force) {
__tlb_reset_range(tlb);
__tlb_adjust_range(tlb, start, end - start);
}
tlb_flush_mmu(tlb);
/* keep the page table cache within bounds */
check_pgt_cache();
for (batch = tlb->local.next; batch; batch = next) {
next = batch->next;
free_pages((unsigned long)batch, 0);
}
tlb->local.next = NULL;
}
/* __tlb_remove_page
* Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while
* handling the additional races in SMP caused by other CPUs caching valid
* mappings in their TLBs. Returns the number of free page slots left.
* When out of page slots we must call tlb_flush_mmu().
*returns true if the caller should flush.
*/
bool __tlb_remove_page_size(struct mmu_gather *tlb, struct page *page, int page_size)
{
struct mmu_gather_batch *batch;
VM_BUG_ON(!tlb->end);
VM_WARN_ON(tlb->page_size != page_size);
batch = tlb->active;
/*
* Add the page and check if we are full. If so
* force a flush.
*/
batch->pages[batch->nr++] = page;
if (batch->nr == batch->max) {
if (!tlb_next_batch(tlb))
return true;
batch = tlb->active;
}
VM_BUG_ON_PAGE(batch->nr > batch->max, page);
return false;
}
#endif /* HAVE_GENERIC_MMU_GATHER */
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
/*
* See the comment near struct mmu_table_batch.
*/
/*
* If we want tlb_remove_table() to imply TLB invalidates.
*/
static inline void tlb_table_invalidate(struct mmu_gather *tlb)
{
#ifdef CONFIG_HAVE_RCU_TABLE_INVALIDATE
/*
* Invalidate page-table caches used by hardware walkers. Then we still
* need to RCU-sched wait while freeing the pages because software
* walkers can still be in-flight.
*/
tlb_flush_mmu_tlbonly(tlb);
#endif
}
static void tlb_remove_table_smp_sync(void *arg)
{
/* Simply deliver the interrupt */
}
static void tlb_remove_table_one(void *table)
{
/*
* This isn't an RCU grace period and hence the page-tables cannot be
* assumed to be actually RCU-freed.
*
* It is however sufficient for software page-table walkers that rely on
* IRQ disabling. See the comment near struct mmu_table_batch.
*/
smp_call_function(tlb_remove_table_smp_sync, NULL, 1);
__tlb_remove_table(table);
}
static void tlb_remove_table_rcu(struct rcu_head *head)
{
struct mmu_table_batch *batch;
int i;
batch = container_of(head, struct mmu_table_batch, rcu);
for (i = 0; i < batch->nr; i++)
__tlb_remove_table(batch->tables[i]);
free_page((unsigned long)batch);
}
void tlb_table_flush(struct mmu_gather *tlb)
{
struct mmu_table_batch **batch = &tlb->batch;
if (*batch) {
tlb_table_invalidate(tlb);
call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu);
*batch = NULL;
}
}
void tlb_remove_table(struct mmu_gather *tlb, void *table)
{
struct mmu_table_batch **batch = &tlb->batch;
if (*batch == NULL) {
*batch = (struct mmu_table_batch *)__get_free_page(GFP_NOWAIT | __GFP_NOWARN);
if (*batch == NULL) {
tlb_table_invalidate(tlb);
tlb_remove_table_one(table);
return;
}
(*batch)->nr = 0;
}
(*batch)->tables[(*batch)->nr++] = table;
if ((*batch)->nr == MAX_TABLE_BATCH)
tlb_table_flush(tlb);
}
#endif /* CONFIG_HAVE_RCU_TABLE_FREE */
/**
* tlb_gather_mmu - initialize an mmu_gather structure for page-table tear-down
* @tlb: the mmu_gather structure to initialize
* @mm: the mm_struct of the target address space
* @start: start of the region that will be removed from the page-table
* @end: end of the region that will be removed from the page-table
*
* Called to initialize an (on-stack) mmu_gather structure for page-table
* tear-down from @mm. The @start and @end are set to 0 and -1
* respectively when @mm is without users and we're going to destroy
* the full address space (exit/execve).
*/
void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
unsigned long start, unsigned long end)
{
arch_tlb_gather_mmu(tlb, mm, start, end);
inc_tlb_flush_pending(tlb->mm);
}
void tlb_finish_mmu(struct mmu_gather *tlb,
unsigned long start, unsigned long end)
{
/*
* If there are parallel threads are doing PTE changes on same range
* under non-exclusive lock(e.g., mmap_sem read-side) but defer TLB
* flush by batching, a thread has stable TLB entry can fail to flush
* the TLB by observing pte_none|!pte_dirty, for example so flush TLB
* forcefully if we detect parallel PTE batching threads.
*/
bool force = mm_tlb_flush_nested(tlb->mm);
arch_tlb_finish_mmu(tlb, start, end, force);
dec_tlb_flush_pending(tlb->mm);
}