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-rw-r--r--mm/page_io.c117
1 files changed, 64 insertions, 53 deletions
diff --git a/mm/page_io.c b/mm/page_io.c
index b995a5ba5..985f23cfa 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -56,31 +56,20 @@ void end_swap_bio_write(struct bio *bio)
* Also clear PG_reclaim to avoid rotate_reclaimable_page()
*/
set_page_dirty(page);
- printk(KERN_ALERT "Write-error on swap-device (%u:%u:%Lu)\n",
- imajor(bio->bi_bdev->bd_inode),
- iminor(bio->bi_bdev->bd_inode),
- (unsigned long long)bio->bi_iter.bi_sector);
+ pr_alert("Write-error on swap-device (%u:%u:%llu)\n",
+ imajor(bio->bi_bdev->bd_inode),
+ iminor(bio->bi_bdev->bd_inode),
+ (unsigned long long)bio->bi_iter.bi_sector);
ClearPageReclaim(page);
}
end_page_writeback(page);
bio_put(bio);
}
-static void end_swap_bio_read(struct bio *bio)
+static void swap_slot_free_notify(struct page *page)
{
- struct page *page = bio->bi_io_vec[0].bv_page;
-
- if (bio->bi_error) {
- SetPageError(page);
- ClearPageUptodate(page);
- printk(KERN_ALERT "Read-error on swap-device (%u:%u:%Lu)\n",
- imajor(bio->bi_bdev->bd_inode),
- iminor(bio->bi_bdev->bd_inode),
- (unsigned long long)bio->bi_iter.bi_sector);
- goto out;
- }
-
- SetPageUptodate(page);
+ struct swap_info_struct *sis;
+ struct gendisk *disk;
/*
* There is no guarantee that the page is in swap cache - the software
@@ -88,42 +77,59 @@ static void end_swap_bio_read(struct bio *bio)
* swapcache page. So we must check PG_swapcache before proceeding with
* this optimization.
*/
- if (likely(PageSwapCache(page))) {
- struct swap_info_struct *sis;
+ if (unlikely(!PageSwapCache(page)))
+ return;
- sis = page_swap_info(page);
- if (sis->flags & SWP_BLKDEV) {
- /*
- * The swap subsystem performs lazy swap slot freeing,
- * expecting that the page will be swapped out again.
- * So we can avoid an unnecessary write if the page
- * isn't redirtied.
- * This is good for real swap storage because we can
- * reduce unnecessary I/O and enhance wear-leveling
- * if an SSD is used as the as swap device.
- * But if in-memory swap device (eg zram) is used,
- * this causes a duplicated copy between uncompressed
- * data in VM-owned memory and compressed data in
- * zram-owned memory. So let's free zram-owned memory
- * and make the VM-owned decompressed page *dirty*,
- * so the page should be swapped out somewhere again if
- * we again wish to reclaim it.
- */
- struct gendisk *disk = sis->bdev->bd_disk;
- if (disk->fops->swap_slot_free_notify) {
- swp_entry_t entry;
- unsigned long offset;
+ sis = page_swap_info(page);
+ if (!(sis->flags & SWP_BLKDEV))
+ return;
- entry.val = page_private(page);
- offset = swp_offset(entry);
+ /*
+ * The swap subsystem performs lazy swap slot freeing,
+ * expecting that the page will be swapped out again.
+ * So we can avoid an unnecessary write if the page
+ * isn't redirtied.
+ * This is good for real swap storage because we can
+ * reduce unnecessary I/O and enhance wear-leveling
+ * if an SSD is used as the as swap device.
+ * But if in-memory swap device (eg zram) is used,
+ * this causes a duplicated copy between uncompressed
+ * data in VM-owned memory and compressed data in
+ * zram-owned memory. So let's free zram-owned memory
+ * and make the VM-owned decompressed page *dirty*,
+ * so the page should be swapped out somewhere again if
+ * we again wish to reclaim it.
+ */
+ disk = sis->bdev->bd_disk;
+ if (disk->fops->swap_slot_free_notify) {
+ swp_entry_t entry;
+ unsigned long offset;
- SetPageDirty(page);
- disk->fops->swap_slot_free_notify(sis->bdev,
- offset);
- }
- }
+ entry.val = page_private(page);
+ offset = swp_offset(entry);
+
+ SetPageDirty(page);
+ disk->fops->swap_slot_free_notify(sis->bdev,
+ offset);
}
+}
+
+static void end_swap_bio_read(struct bio *bio)
+{
+ struct page *page = bio->bi_io_vec[0].bv_page;
+ if (bio->bi_error) {
+ SetPageError(page);
+ ClearPageUptodate(page);
+ pr_alert("Read-error on swap-device (%u:%u:%llu)\n",
+ imajor(bio->bi_bdev->bd_inode),
+ iminor(bio->bi_bdev->bd_inode),
+ (unsigned long long)bio->bi_iter.bi_sector);
+ goto out;
+ }
+
+ SetPageUptodate(page);
+ swap_slot_free_notify(page);
out:
unlock_page(page);
bio_put(bio);
@@ -216,7 +222,7 @@ reprobe:
out:
return ret;
bad_bmap:
- printk(KERN_ERR "swapon: swapfile has holes\n");
+ pr_err("swapon: swapfile has holes\n");
ret = -EINVAL;
goto out;
}
@@ -246,7 +252,7 @@ out:
static sector_t swap_page_sector(struct page *page)
{
- return (sector_t)__page_file_index(page) << (PAGE_CACHE_SHIFT - 9);
+ return (sector_t)__page_file_index(page) << (PAGE_SHIFT - 9);
}
int __swap_writepage(struct page *page, struct writeback_control *wbc,
@@ -290,8 +296,8 @@ int __swap_writepage(struct page *page, struct writeback_control *wbc,
*/
set_page_dirty(page);
ClearPageReclaim(page);
- pr_err_ratelimited("Write error on dio swapfile (%Lu)\n",
- page_file_offset(page));
+ pr_err_ratelimited("Write error on dio swapfile (%llu)\n",
+ page_file_offset(page));
}
end_page_writeback(page);
return ret;
@@ -347,6 +353,11 @@ int swap_readpage(struct page *page)
ret = bdev_read_page(sis->bdev, swap_page_sector(page), page);
if (!ret) {
+ if (trylock_page(page)) {
+ swap_slot_free_notify(page);
+ unlock_page(page);
+ }
+
count_vm_event(PSWPIN);
return 0;
}