Call swap_writeout() and shmem_writeout() from pageout() instead.
Signed-off-by: Matthew Wilcox (Oracle) <wi...@infradead.org>
---
block/blk-wbt.c | 2 +-
mm/page_io.c | 3 +--
mm/shmem.c | 23 +++++------------------
mm/swap.h | 4 ++--
mm/swap_state.c | 1 -
mm/swapfile.c | 2 +-
mm/vmscan.c | 28 ++++++++++++++++------------
7 files changed, 26 insertions(+), 37 deletions(-)
diff --git a/block/blk-wbt.c b/block/blk-wbt.c
index f1754d07f7e0..60885731e8ab 100644
--- a/block/blk-wbt.c
+++ b/block/blk-wbt.c
@@ -37,7 +37,7 @@
enum wbt_flags {
WBT_TRACKED = 1, /* write, tracked for throttling */
WBT_READ = 2, /* read */
- WBT_SWAP = 4, /* write, from swap_writepage() */
+ WBT_SWAP = 4, /* write, from swap_writeout() */
WBT_DISCARD = 8, /* discard */
WBT_NR_BITS = 4, /* number of bits */
diff --git a/mm/page_io.c b/mm/page_io.c
index 9b983de351f9..e9151952c514 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -237,9 +237,8 @@ static void swap_zeromap_folio_clear(struct folio *folio)
* We may have stale swap cache pages in memory: notice
* them here and get rid of the unnecessary final write.
*/
-int swap_writepage(struct page *page, struct writeback_control *wbc)
+int swap_writeout(struct folio *folio, struct writeback_control *wbc)
{
- struct folio *folio = page_folio(page);
int ret;
if (folio_free_swap(folio)) {
diff --git a/mm/shmem.c b/mm/shmem.c
index 427b7f70fffb..a786b94a468a 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -98,7 +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.
*/
@@ -107,7 +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 {
@@ -446,7 +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.
*/
@@ -1536,11 +1536,6 @@ int shmem_unuse(unsigned int type)
return error;
}
-static int shmem_writepage(struct page *page, struct writeback_control *wbc)
-{
- return shmem_writeout(page_folio(page), wbc);
-}
-
/**
* shmem_writeout - Write the folio to swap
* @folio: The folio to write
@@ -1558,13 +1553,6 @@ int shmem_writeout(struct folio *folio, struct
writeback_control *wbc)
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;
@@ -1653,7 +1641,7 @@ int shmem_writeout(struct folio *folio, struct
writeback_control *wbc)
mutex_unlock(&shmem_swaplist_mutex);
BUG_ON(folio_mapped(folio));
- return swap_writepage(&folio->page, wbc);
+ return swap_writeout(folio, wbc);
}
list_del_init(&info->swaplist);
@@ -3780,7 +3768,7 @@ 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))
@@ -5203,7 +5191,6 @@ 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,
diff --git a/mm/swap.h b/mm/swap.h
index 6f4a3f927edb..aa62463976d5 100644
--- a/mm/swap.h
+++ b/mm/swap.h
@@ -20,7 +20,7 @@ static inline void swap_read_unplug(struct swap_iocb *plug)
__swap_read_unplug(plug);
}
void swap_write_unplug(struct swap_iocb *sio);
-int swap_writepage(struct page *page, struct writeback_control *wbc);
+int swap_writeout(struct folio *folio, struct writeback_control *wbc);
void __swap_writepage(struct folio *folio, struct writeback_control *wbc);
/* linux/mm/swap_state.c */
@@ -141,7 +141,7 @@ static inline struct folio *swapin_readahead(swp_entry_t
swp, gfp_t gfp_mask,
return NULL;
}
-static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
+static inline int swap_writeout(struct folio *f, struct writeback_control *wbc)
{
return 0;
}
diff --git a/mm/swap_state.c b/mm/swap_state.c
index 68fd981b514f..ec2b1c9c9926 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -30,7 +30,6 @@
* vmscan's shrink_folio_list.
*/
static const struct address_space_operations swap_aops = {
- .writepage = swap_writepage,
.dirty_folio = noop_dirty_folio,
#ifdef CONFIG_MIGRATION
.migrate_folio = migrate_folio,
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 628f67974a7c..60c994f84842 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2360,7 +2360,7 @@ static int try_to_unuse(unsigned int type)
* Limit the number of retries? No: when mmget_not_zero()
* above fails, that mm is likely to be freeing swap from
* exit_mmap(), which proceeds at its own independent pace;
- * and even shmem_writepage() could have been preempted after
+ * and even shmem_writeout() could have been preempted after
* folio_alloc_swap(), temporarily hiding that swap. It's easy
* and robust (though cpu-intensive) just to keep retrying.
*/
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 34410d24dc15..e9f84fa31b9a 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -648,16 +648,16 @@ typedef enum {
static pageout_t pageout(struct folio *folio, struct address_space *mapping,
struct swap_iocb **plug, struct list_head *folio_list)
{
+ int (*writeout)(struct folio *, struct writeback_control *);
+
/*
- * If the folio is dirty, only perform writeback if that write
- * will be non-blocking. To prevent this allocation from being
- * stalled by pagecache activity. But note that there may be
- * stalls if we need to run get_block(). We could test
- * PagePrivate for that.
- *
- * If this process is currently in __generic_file_write_iter() against
- * this folio's queue, we can perform writeback even if that
- * will block.
+ * We no longer attempt to writeback filesystem folios here, other
+ * than tmpfs/shmem. That's taken care of in page-writeback.
+ * If we find a dirty filesystem folio at the end of the LRU list,
+ * typically that means the filesystem is saturating the storage
+ * with contiguous writes and telling it to write a folio here
+ * would only make the situation worse by injecting an element
+ * of random access.
*
* If the folio is swapcache, write it back even if that would
* block, for some throttling. This happens by accident, because
@@ -680,7 +680,11 @@ static pageout_t pageout(struct folio *folio, struct
address_space *mapping,
}
return PAGE_KEEP;
}
- if (mapping->a_ops->writepage == NULL)
+ if (shmem_mapping(mapping))
+ writeout = shmem_writeout;
+ else if (folio_test_anon(folio))
+ writeout = swap_writeout;
+ else
return PAGE_ACTIVATE;
if (folio_clear_dirty_for_io(folio)) {
@@ -703,7 +707,7 @@ static pageout_t pageout(struct folio *folio, struct
address_space *mapping,
wbc.list = folio_list;
folio_set_reclaim(folio);
- res = mapping->a_ops->writepage(&folio->page, &wbc);
+ res = writeout(folio, &wbc);
if (res < 0)
handle_write_error(mapping, folio, res);
if (res == AOP_WRITEPAGE_ACTIVATE) {
@@ -712,7 +716,7 @@ static pageout_t pageout(struct folio *folio, struct
address_space *mapping,
}
if (!folio_test_writeback(folio)) {
- /* synchronous write or broken a_ops? */
+ /* synchronous write? */
folio_clear_reclaim(folio);
}
trace_mm_vmscan_write_folio(folio);
--
2.47.2
