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Diffstat (limited to 'mm/shmem.c')
-rw-r--r--mm/shmem.c275
1 files changed, 143 insertions, 132 deletions
diff --git a/mm/shmem.c b/mm/shmem.c
index 1dd513d82332..5758e2e3b153 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -86,7 +86,6 @@ static struct vfsmount *shm_mnt __ro_after_init;
#include "internal.h"
-#define BLOCKS_PER_PAGE (PAGE_SIZE/512)
#define VM_ACCT(size) (PAGE_ALIGN(size) >> PAGE_SHIFT)
/* Pretend that each entry is of this size in directory's i_size */
@@ -99,7 +98,7 @@ static struct vfsmount *shm_mnt __ro_after_init;
#define SHORT_SYMLINK_LEN 128
/*
- * shmem_fallocate communicates with shmem_fault or shmem_writepage via
+ * shmem_fallocate communicates with shmem_fault or shmem_writeout via
* inode->i_private (with i_rwsem making sure that it has only one user at
* a time): we would prefer not to enlarge the shmem inode just for that.
*/
@@ -108,7 +107,7 @@ struct shmem_falloc {
pgoff_t start; /* start of range currently being fallocated */
pgoff_t next; /* the next page offset to be fallocated */
pgoff_t nr_falloced; /* how many new pages have been fallocated */
- pgoff_t nr_unswapped; /* how often writepage refused to swap out */
+ pgoff_t nr_unswapped; /* how often writeout refused to swap out */
};
struct shmem_options {
@@ -447,7 +446,7 @@ static void shmem_recalc_inode(struct inode *inode, long alloced, long swapped)
/*
* Special case: whereas normally shmem_recalc_inode() is called
* after i_mapping->nrpages has already been adjusted (up or down),
- * shmem_writepage() has to raise swapped before nrpages is lowered -
+ * shmem_writeout() has to raise swapped before nrpages is lowered -
* to stop a racing shmem_recalc_inode() from thinking that a page has
* been freed. Compensate here, to avoid the need for a followup call.
*/
@@ -526,9 +525,9 @@ static bool shmem_confirm_swap(struct address_space *mapping,
* enables huge pages for the mount;
* SHMEM_HUGE_WITHIN_SIZE:
* only allocate huge pages if the page will be fully within i_size,
- * also respect fadvise()/madvise() hints;
+ * also respect madvise() hints;
* SHMEM_HUGE_ADVISE:
- * only allocate huge pages if requested with fadvise()/madvise();
+ * only allocate huge pages if requested with madvise();
*/
#define SHMEM_HUGE_NEVER 0
@@ -591,6 +590,28 @@ shmem_mapping_size_orders(struct address_space *mapping, pgoff_t index, loff_t w
return order > 0 ? BIT(order + 1) - 1 : 0;
}
+static unsigned int shmem_get_orders_within_size(struct inode *inode,
+ unsigned long within_size_orders, pgoff_t index,
+ loff_t write_end)
+{
+ pgoff_t aligned_index;
+ unsigned long order;
+ loff_t i_size;
+
+ order = highest_order(within_size_orders);
+ while (within_size_orders) {
+ aligned_index = round_up(index + 1, 1 << order);
+ i_size = max(write_end, i_size_read(inode));
+ i_size = round_up(i_size, PAGE_SIZE);
+ if (i_size >> PAGE_SHIFT >= aligned_index)
+ return within_size_orders;
+
+ order = next_order(&within_size_orders, order);
+ }
+
+ return 0;
+}
+
static unsigned int shmem_huge_global_enabled(struct inode *inode, pgoff_t index,
loff_t write_end, bool shmem_huge_force,
struct vm_area_struct *vma,
@@ -599,9 +620,6 @@ static unsigned int shmem_huge_global_enabled(struct inode *inode, pgoff_t index
unsigned int maybe_pmd_order = HPAGE_PMD_ORDER > MAX_PAGECACHE_ORDER ?
0 : BIT(HPAGE_PMD_ORDER);
unsigned long within_size_orders;
- unsigned int order;
- pgoff_t aligned_index;
- loff_t i_size;
if (!S_ISREG(inode->i_mode))
return 0;
@@ -635,16 +653,11 @@ static unsigned int shmem_huge_global_enabled(struct inode *inode, pgoff_t index
within_size_orders = shmem_mapping_size_orders(inode->i_mapping,
index, write_end);
- order = highest_order(within_size_orders);
- while (within_size_orders) {
- aligned_index = round_up(index + 1, 1 << order);
- i_size = max(write_end, i_size_read(inode));
- i_size = round_up(i_size, PAGE_SIZE);
- if (i_size >> PAGE_SHIFT >= aligned_index)
- return within_size_orders;
+ within_size_orders = shmem_get_orders_within_size(inode, within_size_orders,
+ index, write_end);
+ if (within_size_orders > 0)
+ return within_size_orders;
- order = next_order(&within_size_orders, order);
- }
fallthrough;
case SHMEM_HUGE_ADVISE:
if (vm_flags & VM_HUGEPAGE)
@@ -871,7 +884,9 @@ static int shmem_add_to_page_cache(struct folio *folio,
pgoff_t index, void *expected, gfp_t gfp)
{
XA_STATE_ORDER(xas, &mapping->i_pages, index, folio_order(folio));
- long nr = folio_nr_pages(folio);
+ unsigned long nr = folio_nr_pages(folio);
+ swp_entry_t iter, swap;
+ void *entry;
VM_BUG_ON_FOLIO(index != round_down(index, nr), folio);
VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
@@ -883,14 +898,25 @@ static int shmem_add_to_page_cache(struct folio *folio,
gfp &= GFP_RECLAIM_MASK;
folio_throttle_swaprate(folio, gfp);
+ swap = radix_to_swp_entry(expected);
do {
+ iter = swap;
xas_lock_irq(&xas);
- if (expected != xas_find_conflict(&xas)) {
- xas_set_err(&xas, -EEXIST);
- goto unlock;
+ xas_for_each_conflict(&xas, entry) {
+ /*
+ * The range must either be empty, or filled with
+ * expected swap entries. Shmem swap entries are never
+ * partially freed without split of both entry and
+ * folio, so there shouldn't be any holes.
+ */
+ if (!expected || entry != swp_to_radix_entry(iter)) {
+ xas_set_err(&xas, -EEXIST);
+ goto unlock;
+ }
+ iter.val += 1 << xas_get_order(&xas);
}
- if (expected && xas_find_conflict(&xas)) {
+ if (expected && iter.val - nr != swap.val) {
xas_set_err(&xas, -EEXIST);
goto unlock;
}
@@ -1380,9 +1406,9 @@ static void shmem_evict_inode(struct inode *inode)
#endif
}
-static int shmem_find_swap_entries(struct address_space *mapping,
- pgoff_t start, struct folio_batch *fbatch,
- pgoff_t *indices, unsigned int type)
+static unsigned int shmem_find_swap_entries(struct address_space *mapping,
+ pgoff_t start, struct folio_batch *fbatch,
+ pgoff_t *indices, unsigned int type)
{
XA_STATE(xas, &mapping->i_pages, start);
struct folio *folio;
@@ -1415,7 +1441,7 @@ static int shmem_find_swap_entries(struct address_space *mapping,
}
rcu_read_unlock();
- return xas.xa_index;
+ return folio_batch_count(fbatch);
}
/*
@@ -1433,8 +1459,6 @@ static int shmem_unuse_swap_entries(struct inode *inode,
for (i = 0; i < folio_batch_count(fbatch); i++) {
struct folio *folio = fbatch->folios[i];
- if (!xa_is_value(folio))
- continue;
error = shmem_swapin_folio(inode, indices[i], &folio, SGP_CACHE,
mapping_gfp_mask(mapping), NULL, NULL);
if (error == 0) {
@@ -1462,8 +1486,8 @@ static int shmem_unuse_inode(struct inode *inode, unsigned int type)
do {
folio_batch_init(&fbatch);
- shmem_find_swap_entries(mapping, start, &fbatch, indices, type);
- if (folio_batch_count(&fbatch) == 0) {
+ if (!shmem_find_swap_entries(mapping, start, &fbatch,
+ indices, type)) {
ret = 0;
break;
}
@@ -1492,6 +1516,7 @@ int shmem_unuse(unsigned int type)
return 0;
mutex_lock(&shmem_swaplist_mutex);
+start_over:
list_for_each_entry_safe(info, next, &shmem_swaplist, swaplist) {
if (!info->swapped) {
list_del_init(&info->swaplist);
@@ -1510,41 +1535,38 @@ int shmem_unuse(unsigned int type)
cond_resched();
mutex_lock(&shmem_swaplist_mutex);
- next = list_next_entry(info, swaplist);
- if (!info->swapped)
- list_del_init(&info->swaplist);
if (atomic_dec_and_test(&info->stop_eviction))
wake_up_var(&info->stop_eviction);
if (error)
break;
+ if (list_empty(&info->swaplist))
+ goto start_over;
+ next = list_next_entry(info, swaplist);
+ if (!info->swapped)
+ list_del_init(&info->swaplist);
}
mutex_unlock(&shmem_swaplist_mutex);
return error;
}
-/*
- * Move the page from the page cache to the swap cache.
+/**
+ * shmem_writeout - Write the folio to swap
+ * @folio: The folio to write
+ * @wbc: How writeback is to be done
+ *
+ * Move the folio from the page cache to the swap cache.
*/
-static int shmem_writepage(struct page *page, struct writeback_control *wbc)
+int shmem_writeout(struct folio *folio, struct writeback_control *wbc)
{
- struct folio *folio = page_folio(page);
struct address_space *mapping = folio->mapping;
struct inode *inode = mapping->host;
struct shmem_inode_info *info = SHMEM_I(inode);
struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
- swp_entry_t swap;
pgoff_t index;
int nr_pages;
bool split = false;
- /*
- * Our capabilities prevent regular writeback or sync from ever calling
- * shmem_writepage; but a stacking filesystem might use ->writepage of
- * its underlying filesystem, in which case tmpfs should write out to
- * swap only in response to memory pressure, and not for the writeback
- * threads or sync.
- */
if (WARN_ON_ONCE(!wbc->for_reclaim))
goto redirty;
@@ -1574,9 +1596,8 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc)
try_split:
/* Ensure the subpages are still dirty */
folio_test_set_dirty(folio);
- if (split_huge_page_to_list_to_order(page, wbc->list, 0))
+ if (split_folio_to_list(folio, wbc->list))
goto redirty;
- folio = page_folio(page);
folio_clear_dirty(folio);
}
@@ -1615,14 +1636,6 @@ try_split:
folio_mark_uptodate(folio);
}
- swap = folio_alloc_swap(folio);
- if (!swap.val) {
- if (nr_pages > 1)
- goto try_split;
-
- goto redirty;
- }
-
/*
* Add inode to shmem_unuse()'s list of swapped-out inodes,
* if it's not already there. Do it now before the folio is
@@ -1635,20 +1648,20 @@ try_split:
if (list_empty(&info->swaplist))
list_add(&info->swaplist, &shmem_swaplist);
- if (add_to_swap_cache(folio, swap,
- __GFP_HIGH | __GFP_NOMEMALLOC | __GFP_NOWARN,
- NULL) == 0) {
+ if (!folio_alloc_swap(folio, __GFP_HIGH | __GFP_NOMEMALLOC | __GFP_NOWARN)) {
shmem_recalc_inode(inode, 0, nr_pages);
- swap_shmem_alloc(swap, nr_pages);
- shmem_delete_from_page_cache(folio, swp_to_radix_entry(swap));
+ swap_shmem_alloc(folio->swap, nr_pages);
+ shmem_delete_from_page_cache(folio, swp_to_radix_entry(folio->swap));
mutex_unlock(&shmem_swaplist_mutex);
BUG_ON(folio_mapped(folio));
- return swap_writepage(&folio->page, wbc);
+ return swap_writeout(folio, wbc);
}
-
+ if (!info->swapped)
+ list_del_init(&info->swaplist);
mutex_unlock(&shmem_swaplist_mutex);
- put_swap_folio(folio, swap);
+ if (nr_pages > 1)
+ goto try_split;
redirty:
folio_mark_dirty(folio);
if (wbc->for_reclaim)
@@ -1656,6 +1669,7 @@ redirty:
folio_unlock(folio);
return 0;
}
+EXPORT_SYMBOL_GPL(shmem_writeout);
#if defined(CONFIG_NUMA) && defined(CONFIG_TMPFS)
static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol)
@@ -1757,10 +1771,7 @@ unsigned long shmem_allowable_huge_orders(struct inode *inode,
unsigned long mask = READ_ONCE(huge_shmem_orders_always);
unsigned long within_size_orders = READ_ONCE(huge_shmem_orders_within_size);
unsigned long vm_flags = vma ? vma->vm_flags : 0;
- pgoff_t aligned_index;
unsigned int global_orders;
- loff_t i_size;
- int order;
if (thp_disabled_by_hw() || (vma && vma_thp_disabled(vma, vm_flags)))
return 0;
@@ -1786,17 +1797,7 @@ unsigned long shmem_allowable_huge_orders(struct inode *inode,
return READ_ONCE(huge_shmem_orders_inherit);
/* Allow mTHP that will be fully within i_size. */
- order = highest_order(within_size_orders);
- while (within_size_orders) {
- aligned_index = round_up(index + 1, 1 << order);
- i_size = round_up(i_size_read(inode), PAGE_SIZE);
- if (i_size >> PAGE_SHIFT >= aligned_index) {
- mask |= within_size_orders;
- break;
- }
-
- order = next_order(&within_size_orders, order);
- }
+ mask |= shmem_get_orders_within_size(inode, within_size_orders, index, 0);
if (vm_flags & VM_HUGEPAGE)
mask |= READ_ONCE(huge_shmem_orders_madvise);
@@ -2017,7 +2018,7 @@ static struct folio *shmem_swap_alloc_folio(struct inode *inode,
__folio_set_swapbacked(new);
new->swap = entry;
- mem_cgroup_swapin_uncharge_swap(entry, nr_pages);
+ memcg1_swapin(entry, nr_pages);
shadow = get_shadow_from_swap_cache(entry);
if (shadow)
workingset_refault(new, shadow);
@@ -2162,15 +2163,16 @@ static int shmem_split_large_entry(struct inode *inode, pgoff_t index,
{
struct address_space *mapping = inode->i_mapping;
XA_STATE_ORDER(xas, &mapping->i_pages, index, 0);
- void *alloced_shadow = NULL;
- int alloced_order = 0, i;
+ int split_order = 0, entry_order;
+ int i;
/* Convert user data gfp flags to xarray node gfp flags */
gfp &= GFP_RECLAIM_MASK;
for (;;) {
- int order = -1, split_order = 0;
void *old = NULL;
+ int cur_order;
+ pgoff_t swap_index;
xas_lock_irq(&xas);
old = xas_load(&xas);
@@ -2179,60 +2181,56 @@ static int shmem_split_large_entry(struct inode *inode, pgoff_t index,
goto unlock;
}
- order = xas_get_order(&xas);
+ entry_order = xas_get_order(&xas);
- /* Swap entry may have changed before we re-acquire the lock */
- if (alloced_order &&
- (old != alloced_shadow || order != alloced_order)) {
- xas_destroy(&xas);
- alloced_order = 0;
- }
+ if (!entry_order)
+ goto unlock;
/* Try to split large swap entry in pagecache */
- if (order > 0) {
- if (!alloced_order) {
- split_order = order;
+ cur_order = entry_order;
+ swap_index = round_down(index, 1 << entry_order);
+
+ split_order = xas_try_split_min_order(cur_order);
+
+ while (cur_order > 0) {
+ pgoff_t aligned_index =
+ round_down(index, 1 << cur_order);
+ pgoff_t swap_offset = aligned_index - swap_index;
+
+ xas_set_order(&xas, index, split_order);
+ xas_try_split(&xas, old, cur_order);
+ if (xas_error(&xas))
goto unlock;
- }
- xas_split(&xas, old, order);
/*
* Re-set the swap entry after splitting, and the swap
* offset of the original large entry must be continuous.
*/
- for (i = 0; i < 1 << order; i++) {
- pgoff_t aligned_index = round_down(index, 1 << order);
+ for (i = 0; i < 1 << cur_order;
+ i += (1 << split_order)) {
swp_entry_t tmp;
- tmp = swp_entry(swp_type(swap), swp_offset(swap) + i);
+ tmp = swp_entry(swp_type(swap),
+ swp_offset(swap) + swap_offset +
+ i);
__xa_store(&mapping->i_pages, aligned_index + i,
swp_to_radix_entry(tmp), 0);
}
+ cur_order = split_order;
+ split_order = xas_try_split_min_order(split_order);
}
unlock:
xas_unlock_irq(&xas);
- /* split needed, alloc here and retry. */
- if (split_order) {
- xas_split_alloc(&xas, old, split_order, gfp);
- if (xas_error(&xas))
- goto error;
- alloced_shadow = old;
- alloced_order = split_order;
- xas_reset(&xas);
- continue;
- }
-
if (!xas_nomem(&xas, gfp))
break;
}
-error:
if (xas_error(&xas))
return xas_error(&xas);
- return alloced_order;
+ return entry_order;
}
/*
@@ -2274,6 +2272,7 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index,
folio = swap_cache_get_folio(swap, NULL, 0);
order = xa_get_order(&mapping->i_pages, index);
if (!folio) {
+ int nr_pages = 1 << order;
bool fallback_order0 = false;
/* Or update major stats only when swapin succeeds?? */
@@ -2287,9 +2286,12 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index,
* If uffd is active for the vma, we need per-page fault
* fidelity to maintain the uffd semantics, then fallback
* to swapin order-0 folio, as well as for zswap case.
+ * Any existing sub folio in the swap cache also blocks
+ * mTHP swapin.
*/
if (order > 0 && ((vma && unlikely(userfaultfd_armed(vma))) ||
- !zswap_never_enabled()))
+ !zswap_never_enabled() ||
+ non_swapcache_batch(swap, nr_pages) != nr_pages))
fallback_order0 = true;
/* Skip swapcache for synchronous device. */
@@ -2338,7 +2340,7 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index,
error = -ENOMEM;
goto failed;
}
- } else if (order != folio_order(folio)) {
+ } else if (order > folio_order(folio)) {
/*
* Swap readahead may swap in order 0 folios into swapcache
* asynchronously, while the shmem mapping can still stores
@@ -2347,6 +2349,8 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index,
*/
split_order = shmem_split_large_entry(inode, index, swap, gfp);
if (split_order < 0) {
+ folio_put(folio);
+ folio = NULL;
error = split_order;
goto failed;
}
@@ -2361,15 +2365,23 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index,
swap = swp_entry(swp_type(swap), swp_offset(swap) + offset);
}
+ } else if (order < folio_order(folio)) {
+ swap.val = round_down(swap.val, 1 << folio_order(folio));
+ index = round_down(index, 1 << folio_order(folio));
}
alloced:
- /* We have to do this with folio locked to prevent races */
+ /*
+ * We have to do this with the folio locked to prevent races.
+ * The shmem_confirm_swap below only checks if the first swap
+ * entry matches the folio, that's enough to ensure the folio
+ * is not used outside of shmem, as shmem swap entries
+ * and swap cache folios are never partially freed.
+ */
folio_lock(folio);
if ((!skip_swapcache && !folio_test_swapcache(folio)) ||
- folio->swap.val != swap.val ||
!shmem_confirm_swap(mapping, index, swap) ||
- xa_get_order(&mapping->i_pages, index) != folio_order(folio)) {
+ folio->swap.val != swap.val) {
error = -EEXIST;
goto unlock;
}
@@ -3780,7 +3792,7 @@ static long shmem_fallocate(struct file *file, int mode, loff_t offset,
index--;
/*
- * Inform shmem_writepage() how far we have reached.
+ * Inform shmem_writeout() how far we have reached.
* No need for lock or barrier: we have the page lock.
*/
if (!folio_test_uptodate(folio))
@@ -3911,16 +3923,16 @@ out_iput:
return error;
}
-static int shmem_mkdir(struct mnt_idmap *idmap, struct inode *dir,
- struct dentry *dentry, umode_t mode)
+static struct dentry *shmem_mkdir(struct mnt_idmap *idmap, struct inode *dir,
+ struct dentry *dentry, umode_t mode)
{
int error;
error = shmem_mknod(idmap, dir, dentry, mode | S_IFDIR, 0);
if (error)
- return error;
+ return ERR_PTR(error);
inc_nlink(dir);
- return 0;
+ return NULL;
}
static int shmem_create(struct mnt_idmap *idmap, struct inode *dir,
@@ -5203,7 +5215,6 @@ static int shmem_error_remove_folio(struct address_space *mapping,
}
static const struct address_space_operations shmem_aops = {
- .writepage = shmem_writepage,
.dirty_folio = noop_dirty_folio,
#ifdef CONFIG_TMPFS
.write_begin = shmem_write_begin,
@@ -5673,19 +5684,19 @@ static int __init setup_thp_shmem(char *str)
THP_ORDERS_ALL_FILE_DEFAULT);
}
- if (start == -EINVAL) {
+ if (start < 0) {
pr_err("invalid size %s in thp_shmem boot parameter\n",
start_size);
goto err;
}
- if (end == -EINVAL) {
+ if (end < 0) {
pr_err("invalid size %s in thp_shmem boot parameter\n",
end_size);
goto err;
}
- if (start < 0 || end < 0 || start > end)
+ if (start > end)
goto err;
nr = end - start + 1;
@@ -5822,12 +5833,12 @@ static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name,
if (size < 0 || size > MAX_LFS_FILESIZE)
return ERR_PTR(-EINVAL);
- if (shmem_acct_size(flags, size))
- return ERR_PTR(-ENOMEM);
-
if (is_idmapped_mnt(mnt))
return ERR_PTR(-EINVAL);
+ if (shmem_acct_size(flags, size))
+ return ERR_PTR(-ENOMEM);
+
inode = shmem_get_inode(&nop_mnt_idmap, mnt->mnt_sb, NULL,
S_IFREG | S_IRWXUGO, 0, flags);
if (IS_ERR(inode)) {
@@ -5852,7 +5863,7 @@ static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name,
* underlying inode. So users of this interface must do LSM checks at a
* higher layer. The users are the big_key and shm implementations. LSM
* checks are provided at the key or shm level rather than the inode.
- * @name: name for dentry (to be seen in /proc/<pid>/maps
+ * @name: name for dentry (to be seen in /proc/<pid>/maps)
* @size: size to be set for the file
* @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
*/
@@ -5864,7 +5875,7 @@ EXPORT_SYMBOL_GPL(shmem_kernel_file_setup);
/**
* shmem_file_setup - get an unlinked file living in tmpfs
- * @name: name for dentry (to be seen in /proc/<pid>/maps
+ * @name: name for dentry (to be seen in /proc/<pid>/maps)
* @size: size to be set for the file
* @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
*/
@@ -5877,7 +5888,7 @@ EXPORT_SYMBOL_GPL(shmem_file_setup);
/**
* shmem_file_setup_with_mnt - get an unlinked file living in tmpfs
* @mnt: the tmpfs mount where the file will be created
- * @name: name for dentry (to be seen in /proc/<pid>/maps
+ * @name: name for dentry (to be seen in /proc/<pid>/maps)
* @size: size to be set for the file
* @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
*/
@@ -5938,8 +5949,8 @@ struct folio *shmem_read_folio_gfp(struct address_space *mapping,
struct folio *folio;
int error;
- error = shmem_get_folio_gfp(inode, index, 0, &folio, SGP_CACHE,
- gfp, NULL, NULL);
+ error = shmem_get_folio_gfp(inode, index, i_size_read(inode),
+ &folio, SGP_CACHE, gfp, NULL, NULL);
if (error)
return ERR_PTR(error);