Commit 9e18eb29 authored by Andres Lagar-Cavilla's avatar Andres Lagar-Cavilla Committed by Linus Torvalds
Browse files

tmpfs: mem_cgroup charge fault to vm_mm not current mm 



Although shmem_fault() has been careful to count a major fault to vm_mm,
shmem_getpage_gfp() has been careless in charging a remote access fault
to current->mm owner's memcg instead of to vma->vm_mm owner's memcg:
that is inconsistent with all the mem_cgroup charging on remote access
faults in mm/memory.c.

Fix it by passing fault_mm along with fault_type to
shmem_get_page_gfp(); but in that case, now knowing the right mm, it's
better for it to handle the PGMAJFAULT updates itself.

And let's keep this clutter out of most callers' way: change the common
shmem_getpage() wrapper to hide fault_mm and fault_type as well as gfp.

Signed-off-by: default avatarAndres Lagar-Cavilla <andreslc@google.com>
Signed-off-by: default avatarHugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andres Lagar-Cavilla <andreslc@google.com>
Cc: Yang Shi <yang.shi@linaro.org>
Cc: Ning Qu <quning@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 75edd345

mm/shmem.c

+34 −27
Original line number Diff line number Diff line
@@ -121,13 +121,14 @@ static bool shmem_should_replace_page(struct page *page, gfp_t gfp); 
static int shmem_replace_page(struct page **pagep, gfp_t gfp,

				struct shmem_inode_info *info, pgoff_t index);

static int shmem_getpage_gfp(struct inode *inode, pgoff_t index,

	struct page **pagep, enum sgp_type sgp, gfp_t gfp, int *fault_type);

		struct page **pagep, enum sgp_type sgp,

		gfp_t gfp, struct mm_struct *fault_mm, int *fault_type);



static inline int shmem_getpage(struct inode *inode, pgoff_t index,

	struct page **pagep, enum sgp_type sgp, int *fault_type)

		struct page **pagep, enum sgp_type sgp)

{

	return shmem_getpage_gfp(inode, index, pagep, sgp,

			mapping_gfp_mask(inode->i_mapping), fault_type);

		mapping_gfp_mask(inode->i_mapping), NULL, NULL);

}



static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb)
@@ -527,7 +528,7 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend, 


	if (partial_start) {

		struct page *page = NULL;

		shmem_getpage(inode, start - 1, &page, SGP_READ, NULL);

		shmem_getpage(inode, start - 1, &page, SGP_READ);

		if (page) {

			unsigned int top = PAGE_SIZE;

			if (start > end) {
@@ -542,7 +543,7 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend, 
	}

	if (partial_end) {

		struct page *page = NULL;

		shmem_getpage(inode, end, &page, SGP_READ, NULL);

		shmem_getpage(inode, end, &page, SGP_READ);

		if (page) {

			zero_user_segment(page, 0, partial_end);

			set_page_dirty(page);
@@ -1115,14 +1116,19 @@ static int shmem_replace_page(struct page **pagep, gfp_t gfp, 
 *

 * If we allocate a new one we do not mark it dirty. That's up to the

 * vm. If we swap it in we mark it dirty since we also free the swap

 * entry since a page cannot live in both the swap and page cache

 * entry since a page cannot live in both the swap and page cache.

 *

 * fault_mm and fault_type are only supplied by shmem_fault:

 * otherwise they are NULL.

 */

static int shmem_getpage_gfp(struct inode *inode, pgoff_t index,

	struct page **pagep, enum sgp_type sgp, gfp_t gfp, int *fault_type)

	struct page **pagep, enum sgp_type sgp, gfp_t gfp,

	struct mm_struct *fault_mm, int *fault_type)

{

	struct address_space *mapping = inode->i_mapping;

	struct shmem_inode_info *info;

	struct shmem_sb_info *sbinfo;

	struct mm_struct *charge_mm;

	struct mem_cgroup *memcg;

	struct page *page;

	swp_entry_t swap;
@@ -1168,14 +1174,19 @@ repeat: 
	 */

	info = SHMEM_I(inode);

	sbinfo = SHMEM_SB(inode->i_sb);

	charge_mm = fault_mm ? : current->mm;



	if (swap.val) {

		/* Look it up and read it in.. */

		page = lookup_swap_cache(swap);

		if (!page) {

			/* here we actually do the io */

			if (fault_type)

			/* Or update major stats only when swapin succeeds?? */

			if (fault_type) {

				*fault_type |= VM_FAULT_MAJOR;

				count_vm_event(PGMAJFAULT);

				mem_cgroup_count_vm_event(fault_mm, PGMAJFAULT);

			}

			/* Here we actually start the io */

			page = shmem_swapin(swap, gfp, info, index);

			if (!page) {

				error = -ENOMEM;
@@ -1202,7 +1213,7 @@ repeat: 
				goto failed;

		}



		error = mem_cgroup_try_charge(page, current->mm, gfp, &memcg,

		error = mem_cgroup_try_charge(page, charge_mm, gfp, &memcg,

				false);

		if (!error) {

			error = shmem_add_to_page_cache(page, mapping, index,
@@ -1263,7 +1274,7 @@ repeat: 
		if (sgp == SGP_WRITE)

			__SetPageReferenced(page);



		error = mem_cgroup_try_charge(page, current->mm, gfp, &memcg,

		error = mem_cgroup_try_charge(page, charge_mm, gfp, &memcg,

				false);

		if (error)

			goto decused;
@@ -1352,6 +1363,7 @@ unlock: 
static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)

{

	struct inode *inode = file_inode(vma->vm_file);

	gfp_t gfp = mapping_gfp_mask(inode->i_mapping);

	int error;

	int ret = VM_FAULT_LOCKED;
@@ -1413,14 +1425,10 @@ static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 
		spin_unlock(&inode->i_lock);

	}



	error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret);

	error = shmem_getpage_gfp(inode, vmf->pgoff, &vmf->page, SGP_CACHE,

				  gfp, vma->vm_mm, &ret);

	if (error)

		return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS);



	if (ret & VM_FAULT_MAJOR) {

		count_vm_event(PGMAJFAULT);

		mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT);

	}

	return ret;

}
@@ -1567,7 +1575,7 @@ shmem_write_begin(struct file *file, struct address_space *mapping, 
			return -EPERM;

	}



	return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL);

	return shmem_getpage(inode, index, pagep, SGP_WRITE);

}



static int
@@ -1633,7 +1641,7 @@ static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to) 
				break;

		}



		error = shmem_getpage(inode, index, &page, sgp, NULL);

		error = shmem_getpage(inode, index, &page, sgp);

		if (error) {

			if (error == -EINVAL)

				error = 0;
@@ -1749,7 +1757,7 @@ static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos, 
	error = 0;



	while (spd.nr_pages < nr_pages) {

		error = shmem_getpage(inode, index, &page, SGP_CACHE, NULL);

		error = shmem_getpage(inode, index, &page, SGP_CACHE);

		if (error)

			break;

		unlock_page(page);
@@ -1771,8 +1779,7 @@ static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos, 
		page = spd.pages[page_nr];



		if (!PageUptodate(page) || page->mapping != mapping) {

			error = shmem_getpage(inode, index, &page,

							SGP_CACHE, NULL);

			error = shmem_getpage(inode, index, &page, SGP_CACHE);

			if (error)

				break;

			unlock_page(page);
@@ -2215,8 +2222,7 @@ static long shmem_fallocate(struct file *file, int mode, loff_t offset, 
		else if (shmem_falloc.nr_unswapped > shmem_falloc.nr_falloced)

			error = -ENOMEM;

		else

			error = shmem_getpage(inode, index, &page, SGP_FALLOC,

									NULL);

			error = shmem_getpage(inode, index, &page, SGP_FALLOC);

		if (error) {

			/* Remove the !PageUptodate pages we added */

			shmem_undo_range(inode,
@@ -2534,7 +2540,7 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s 
		inode->i_op = &shmem_short_symlink_operations;

	} else {

		inode_nohighmem(inode);

		error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL);

		error = shmem_getpage(inode, 0, &page, SGP_WRITE);

		if (error) {

			iput(inode);

			return error;
@@ -2575,7 +2581,7 @@ static const char *shmem_get_link(struct dentry *dentry, 
			return ERR_PTR(-ECHILD);

		}

	} else {

		error = shmem_getpage(inode, 0, &page, SGP_READ, NULL);

		error = shmem_getpage(inode, 0, &page, SGP_READ);

		if (error)

			return ERR_PTR(error);

		unlock_page(page);
@@ -3479,7 +3485,8 @@ struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, 
	int error;



	BUG_ON(mapping->a_ops != &shmem_aops);

	error = shmem_getpage_gfp(inode, index, &page, SGP_CACHE, gfp, NULL);

	error = shmem_getpage_gfp(inode, index, &page, SGP_CACHE,

				  gfp, NULL, NULL);

	if (error)

		page = ERR_PTR(error);

	else

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