writeback: remove nonblocking/encountered_congestion references
This removes more dead code that was somehow missed by commit 0d99519efe
(writeback: remove unused nonblocking and congestion checks). There are
no behavior change except for the removal of two entries from one of the
ext4 tracing interface.
The nonblocking checks in ->writepages are no longer used because the
flusher now prefer to block on get_request_wait() than to skip inodes on
IO congestion. The latter will lead to more seeky IO.
The nonblocking checks in ->writepage are no longer used because it's
redundant with the WB_SYNC_NONE check.
We no long set ->nonblocking in VM page out and page migration, because
a) it's effectively redundant with WB_SYNC_NONE in current code
b) it's old semantic of "Don't get stuck on request queues" is mis-behavior:
that would skip some dirty inodes on congestion and page out others, which
is unfair in terms of LRU age.
Inspired by Christoph Hellwig. Thanks!
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: David Howells <dhowells@redhat.com>
Cc: Sage Weil <sage@newdream.net>
Cc: Steve French <sfrench@samba.org>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
parent
d19d5476f4
commit
1b430beee5
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@ -438,7 +438,6 @@ no_more:
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*/
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int afs_writepage(struct page *page, struct writeback_control *wbc)
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{
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struct backing_dev_info *bdi = page->mapping->backing_dev_info;
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struct afs_writeback *wb;
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int ret;
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@ -455,8 +454,6 @@ int afs_writepage(struct page *page, struct writeback_control *wbc)
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}
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wbc->nr_to_write -= ret;
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if (wbc->nonblocking && bdi_write_congested(bdi))
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wbc->encountered_congestion = 1;
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_leave(" = 0");
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return 0;
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@ -469,7 +466,6 @@ static int afs_writepages_region(struct address_space *mapping,
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struct writeback_control *wbc,
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pgoff_t index, pgoff_t end, pgoff_t *_next)
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{
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struct backing_dev_info *bdi = mapping->backing_dev_info;
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struct afs_writeback *wb;
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struct page *page;
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int ret, n;
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@ -529,11 +525,6 @@ static int afs_writepages_region(struct address_space *mapping,
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wbc->nr_to_write -= ret;
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if (wbc->nonblocking && bdi_write_congested(bdi)) {
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wbc->encountered_congestion = 1;
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break;
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}
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cond_resched();
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} while (index < end && wbc->nr_to_write > 0);
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@ -548,24 +539,16 @@ static int afs_writepages_region(struct address_space *mapping,
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int afs_writepages(struct address_space *mapping,
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struct writeback_control *wbc)
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{
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struct backing_dev_info *bdi = mapping->backing_dev_info;
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pgoff_t start, end, next;
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int ret;
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_enter("");
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if (wbc->nonblocking && bdi_write_congested(bdi)) {
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wbc->encountered_congestion = 1;
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_leave(" = 0 [congest]");
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return 0;
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}
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if (wbc->range_cyclic) {
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start = mapping->writeback_index;
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end = -1;
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ret = afs_writepages_region(mapping, wbc, start, end, &next);
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if (start > 0 && wbc->nr_to_write > 0 && ret == 0 &&
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!(wbc->nonblocking && wbc->encountered_congestion))
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if (start > 0 && wbc->nr_to_write > 0 && ret == 0)
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ret = afs_writepages_region(mapping, wbc, 0, start,
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&next);
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mapping->writeback_index = next;
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@ -1706,7 +1706,7 @@ static int __block_write_full_page(struct inode *inode, struct page *page,
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* and kswapd activity, but those code paths have their own
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* higher-level throttling.
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*/
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if (wbc->sync_mode != WB_SYNC_NONE || !wbc->nonblocking) {
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if (wbc->sync_mode != WB_SYNC_NONE) {
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lock_buffer(bh);
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} else if (!trylock_buffer(bh)) {
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redirty_page_for_writepage(wbc, page);
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@ -591,7 +591,6 @@ static int ceph_writepages_start(struct address_space *mapping,
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struct writeback_control *wbc)
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{
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struct inode *inode = mapping->host;
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struct backing_dev_info *bdi = mapping->backing_dev_info;
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struct ceph_inode_info *ci = ceph_inode(inode);
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struct ceph_fs_client *fsc;
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pgoff_t index, start, end;
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@ -633,13 +632,6 @@ static int ceph_writepages_start(struct address_space *mapping,
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pagevec_init(&pvec, 0);
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/* ?? */
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if (wbc->nonblocking && bdi_write_congested(bdi)) {
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dout(" writepages congested\n");
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wbc->encountered_congestion = 1;
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goto out_final;
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}
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/* where to start/end? */
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if (wbc->range_cyclic) {
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start = mapping->writeback_index; /* Start from prev offset */
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@ -885,7 +877,6 @@ out:
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rc = 0; /* vfs expects us to return 0 */
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ceph_put_snap_context(snapc);
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dout("writepages done, rc = %d\n", rc);
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out_final:
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return rc;
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}
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@ -1303,7 +1303,6 @@ static int cifs_partialpagewrite(struct page *page, unsigned from, unsigned to)
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static int cifs_writepages(struct address_space *mapping,
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struct writeback_control *wbc)
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{
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struct backing_dev_info *bdi = mapping->backing_dev_info;
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unsigned int bytes_to_write;
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unsigned int bytes_written;
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struct cifs_sb_info *cifs_sb;
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@ -1326,15 +1325,6 @@ static int cifs_writepages(struct address_space *mapping,
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int scanned = 0;
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int xid, long_op;
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/*
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* BB: Is this meaningful for a non-block-device file system?
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* If it is, we should test it again after we do I/O
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*/
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if (wbc->nonblocking && bdi_write_congested(bdi)) {
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wbc->encountered_congestion = 1;
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return 0;
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}
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cifs_sb = CIFS_SB(mapping->host->i_sb);
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/*
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@ -55,7 +55,7 @@ static int gfs2_aspace_writepage(struct page *page, struct writeback_control *wb
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* activity, but those code paths have their own higher-level
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* throttling.
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*/
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if (wbc->sync_mode != WB_SYNC_NONE || !wbc->nonblocking) {
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if (wbc->sync_mode != WB_SYNC_NONE) {
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lock_buffer(bh);
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} else if (!trylock_buffer(bh)) {
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redirty_page_for_writepage(wbc, page);
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@ -290,9 +290,7 @@ static int nfs_do_writepage(struct page *page, struct writeback_control *wbc, st
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nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1);
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nfs_pageio_cond_complete(pgio, page->index);
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ret = nfs_page_async_flush(pgio, page,
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wbc->sync_mode == WB_SYNC_NONE ||
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wbc->nonblocking != 0);
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ret = nfs_page_async_flush(pgio, page, wbc->sync_mode == WB_SYNC_NONE);
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if (ret == -EAGAIN) {
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redirty_page_for_writepage(wbc, page);
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ret = 0;
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@ -2438,7 +2438,7 @@ static int reiserfs_write_full_page(struct page *page,
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/* from this point on, we know the buffer is mapped to a
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* real block and not a direct item
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*/
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if (wbc->sync_mode != WB_SYNC_NONE || !wbc->nonblocking) {
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if (wbc->sync_mode != WB_SYNC_NONE) {
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lock_buffer(bh);
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} else {
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if (!trylock_buffer(bh)) {
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@ -1139,8 +1139,7 @@ xfs_vm_writepage(
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type = IO_DELAY;
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flags = BMAPI_ALLOCATE;
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if (wbc->sync_mode == WB_SYNC_NONE &&
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wbc->nonblocking)
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if (wbc->sync_mode == WB_SYNC_NONE)
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flags |= BMAPI_TRYLOCK;
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}
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@ -242,18 +242,20 @@ TRACE_EVENT(ext4_da_writepages,
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__entry->pages_skipped = wbc->pages_skipped;
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__entry->range_start = wbc->range_start;
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__entry->range_end = wbc->range_end;
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__entry->nonblocking = wbc->nonblocking;
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__entry->for_kupdate = wbc->for_kupdate;
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__entry->for_reclaim = wbc->for_reclaim;
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__entry->range_cyclic = wbc->range_cyclic;
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__entry->writeback_index = inode->i_mapping->writeback_index;
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),
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TP_printk("dev %s ino %lu nr_to_write %ld pages_skipped %ld range_start %llu range_end %llu nonblocking %d for_kupdate %d for_reclaim %d range_cyclic %d writeback_index %lu",
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TP_printk("dev %s ino %lu nr_to_write %ld pages_skipped %ld "
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"range_start %llu range_end %llu "
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"for_kupdate %d for_reclaim %d "
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"range_cyclic %d writeback_index %lu",
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jbd2_dev_to_name(__entry->dev),
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(unsigned long) __entry->ino, __entry->nr_to_write,
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__entry->pages_skipped, __entry->range_start,
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__entry->range_end, __entry->nonblocking,
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__entry->range_end,
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__entry->for_kupdate, __entry->for_reclaim,
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__entry->range_cyclic,
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(unsigned long) __entry->writeback_index)
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@ -96,8 +96,6 @@ DECLARE_EVENT_CLASS(wbc_class,
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__field(long, nr_to_write)
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__field(long, pages_skipped)
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__field(int, sync_mode)
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__field(int, nonblocking)
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__field(int, encountered_congestion)
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__field(int, for_kupdate)
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__field(int, for_background)
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__field(int, for_reclaim)
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@ -497,7 +497,6 @@ static int writeout(struct address_space *mapping, struct page *page)
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.nr_to_write = 1,
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.range_start = 0,
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.range_end = LLONG_MAX,
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.nonblocking = 1,
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.for_reclaim = 1
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};
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int rc;
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@ -376,7 +376,6 @@ static pageout_t pageout(struct page *page, struct address_space *mapping,
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.nr_to_write = SWAP_CLUSTER_MAX,
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.range_start = 0,
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.range_end = LLONG_MAX,
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.nonblocking = 1,
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.for_reclaim = 1,
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};
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