diff options
Diffstat (limited to 'fs/fs-writeback.c')
| -rw-r--r-- | fs/fs-writeback.c | 32 |
1 files changed, 21 insertions, 11 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index a07b8cf73ae2..3bfc430ef74d 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -445,22 +445,23 @@ static bool inode_do_switch_wbs(struct inode *inode, * Transfer to @new_wb's IO list if necessary. If the @inode is dirty, * the specific list @inode was on is ignored and the @inode is put on * ->b_dirty which is always correct including from ->b_dirty_time. - * The transfer preserves @inode->dirtied_when ordering. If the @inode - * was clean, it means it was on the b_attached list, so move it onto - * the b_attached list of @new_wb. + * If the @inode was clean, it means it was on the b_attached list, so + * move it onto the b_attached list of @new_wb. */ if (!list_empty(&inode->i_io_list)) { inode->i_wb = new_wb; if (inode->i_state & I_DIRTY_ALL) { - struct inode *pos; - - list_for_each_entry(pos, &new_wb->b_dirty, i_io_list) - if (time_after_eq(inode->dirtied_when, - pos->dirtied_when)) - break; + /* + * We need to keep b_dirty list sorted by + * dirtied_time_when. However properly sorting the + * inode in the list gets too expensive when switching + * many inodes. So just attach inode at the end of the + * dirty list and clobber the dirtied_time_when. + */ + inode->dirtied_time_when = jiffies; inode_io_list_move_locked(inode, new_wb, - pos->i_io_list.prev); + &new_wb->b_dirty); } else { inode_cgwb_move_to_attached(inode, new_wb); } @@ -502,6 +503,7 @@ static void inode_switch_wbs_work_fn(struct work_struct *work) */ down_read(&bdi->wb_switch_rwsem); + inodep = isw->inodes; /* * By the time control reaches here, RCU grace period has passed * since I_WB_SWITCH assertion and all wb stat update transactions @@ -512,6 +514,7 @@ static void inode_switch_wbs_work_fn(struct work_struct *work) * gives us exclusion against all wb related operations on @inode * including IO list manipulations and stat updates. */ +relock: if (old_wb < new_wb) { spin_lock(&old_wb->list_lock); spin_lock_nested(&new_wb->list_lock, SINGLE_DEPTH_NESTING); @@ -520,10 +523,17 @@ static void inode_switch_wbs_work_fn(struct work_struct *work) spin_lock_nested(&old_wb->list_lock, SINGLE_DEPTH_NESTING); } - for (inodep = isw->inodes; *inodep; inodep++) { + while (*inodep) { WARN_ON_ONCE((*inodep)->i_wb != old_wb); if (inode_do_switch_wbs(*inodep, old_wb, new_wb)) nr_switched++; + inodep++; + if (*inodep && need_resched()) { + spin_unlock(&new_wb->list_lock); + spin_unlock(&old_wb->list_lock); + cond_resched(); + goto relock; + } } spin_unlock(&new_wb->list_lock); |