litmus-rt.git - The LITMUS^RT kernel.

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author	Linus Torvalds <torvalds@linux-foundation.org>	2013-04-14 14:12:17 -0400
committer	Linus Torvalds <torvalds@linux-foundation.org>	2013-04-14 14:12:17 -0400
commit	af788e35bff2b98a413c3e81b13c2a27ef6b7528 (patch)
tree	517e7406fb42018a81f558def284a96948fd5002 /drivers/gpu/drm/drm_trace_points.c
parent	ae9f4939bad09767c0532f76ccc48cec0ff3ea4e (diff)
parent	e614b3332a4f3f264a26da28e5a1f4cc3aea3974 (diff)

Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fixes from Ingo Molnar: "Misc fixlets" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/cputime: Fix accounting on multi-threaded processes sched/debug: Fix sd->*_idx limit range avoiding overflow sched_clock: Prevent 64bit inatomicity on 32bit systems sched: Convert BUG_ON()s in try_to_wake_up_local() to WARN_ON_ONCE()s

Diffstat (limited to 'drivers/gpu/drm/drm_trace_points.c')

0 files changed, 0 insertions, 0 deletions

/* * fs/fs-writeback.c * * Copyright (C) 2002, Linus Torvalds. * * Contains all the functions related to writing back and waiting * upon dirty inodes against superblocks, and writing back dirty * pages against inodes. ie: data writeback. Writeout of the * inode itself is not handled here. * * 10Apr2002 Andrew Morton * Split out of fs/inode.c * Additions for address_space-based writeback */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/spinlock.h> #include <linux/sched.h> #include <linux/fs.h> #include <linux/mm.h> #include <linux/writeback.h> #include <linux/blkdev.h> #include <linux/backing-dev.h> #include <linux/buffer_head.h> #include "internal.h" /** * writeback_acquire - attempt to get exclusive writeback access to a device * @bdi: the device's backing_dev_info structure * * It is a waste of resources to have more than one pdflush thread blocked on * a single request queue. Exclusion at the request_queue level is obtained * via a flag in the request_queue's backing_dev_info.state. * * Non-request_queue-backed address_spaces will share default_backing_dev_info, * unless they implement their own. Which is somewhat inefficient, as this * may prevent concurrent writeback against multiple devices. */ static int writeback_acquire(struct backing_dev_info *bdi) { return !test_and_set_bit(BDI_pdflush, &bdi->state); } /** * writeback_in_progress - determine whether there is writeback in progress * @bdi: the device's backing_dev_info structure. * * Determine whether there is writeback in progress against a backing device. */ int writeback_in_progress(struct backing_dev_info *bdi) { return test_bit(BDI_pdflush, &bdi->state); } /** * writeback_release - relinquish exclusive writeback access against a device. * @bdi: the device's backing_dev_info structure */ static void writeback_release(struct backing_dev_info *bdi) { BUG_ON(!writeback_in_progress(bdi)); clear_bit(BDI_pdflush, &bdi->state); } /** * __mark_inode_dirty - internal function * @inode: inode to mark * @flags: what kind of dirty (i.e. I_DIRTY_SYNC) * Mark an inode as dirty. Callers should use mark_inode_dirty or * mark_inode_dirty_sync. * * Put the inode on the super block's dirty list. * * CAREFUL! We mark it dirty unconditionally, but move it onto the * dirty list only if it is hashed or if it refers to a blockdev. * If it was not hashed, it will never be added to the dirty list * even if it is later hashed, as it will have been marked dirty already. * * In short, make sure you hash any inodes _before_ you start marking * them dirty. * * This function *must* be atomic for the I_DIRTY_PAGES case - * set_page_dirty() is called under spinlock in several places. * * Note that for blockdevs, inode->dirtied_when represents the dirtying time of * the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of * the kernel-internal blockdev inode represents the dirtying time of the * blockdev's pages. This is why for I_DIRTY_PAGES we always use * page->mapping->host, so the page-dirtying time is recorded in the internal * blockdev inode. */ void __mark_inode_dirty(struct inode *inode, int flags) { struct super_block *sb = inode->i_sb; /* * Don't do this for I_DIRTY_PAGES - that doesn't actually * dirty the inode itself */ if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { if (sb->s_op->dirty_inode) sb->s_op->dirty_inode(inode); } /* * make sure that changes are seen by all cpus before we test i_state * -- mikulas */ smp_mb(); /* avoid the locking if we can */ if ((inode->i_state & flags) == flags) return; if (unlikely(block_dump)) { struct dentry *dentry = NULL; const char *name = "?"; if (!list_empty(&inode->i_dentry)) { dentry = list_entry(inode->i_dentry.next, struct dentry, d_alias); if (dentry && dentry->d_name.name) name = (const char *) dentry->d_name.name; } if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) printk(KERN_DEBUG "%s(%d): dirtied inode %lu (%s) on %s\n", current->comm, task_pid_nr(current), inode->i_ino, name, inode->i_sb->s_id); } spin_lock(&inode_lock); if ((inode->i_state & flags) != flags) { const int was_dirty = inode->i_state & I_DIRTY; inode->i_state |= flags; /* * If the inode is being synced, just update its dirty state. * The unlocker will place the inode on the appropriate * superblock list, based upon its state. */ if (inode->i_state & I_SYNC) goto out; /* * Only add valid (hashed) inodes to the superblock's * dirty list. Add blockdev inodes as well. */ if (!S_ISBLK(inode->i_mode)) { if (hlist_unhashed(&inode->i_hash)) goto out; } if (inode->i_state & (I_FREEING|I_CLEAR)) goto out; /* * If the inode was already on s_dirty/s_io/s_more_io, don't * reposition it (that would break s_dirty time-ordering). */ if (!was_dirty) { inode->dirtied_when = jiffies; list_move(&inode->i_list, &sb->s_dirty); } } out: spin_unlock(&inode_lock); } EXPORT_SYMBOL(__mark_inode_dirty); static int write_inode(struct inode *inode, int sync) { if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode)) return inode->i_sb->s_op->write_inode(inode, sync); return 0; } /* * Redirty an inode: set its when-it-was dirtied timestamp and move it to the * furthest end of its superblock's dirty-inode list. * * Before stamping the inode's ->dirtied_when, we check to see whether it is * already the most-recently-dirtied inode on the s_dirty list. If that is * the case then the inode must have been redirtied while it was being written * out and we don't reset its dirtied_when. */ static void redirty_tail(struct inode *inode) { struct super_block *sb = inode->i_sb; if (!list_empty(&sb->s_dirty)) { struct inode *tail_inode; tail_inode = list_entry(sb->s_dirty.next, struct inode, i_list); if (!time_after_eq(inode->dirtied_when, tail_inode->dirtied_when)) inode->dirtied_when = jiffies; } list_move(&inode->i_list, &sb->s_dirty); } /* * requeue inode for re-scanning after sb->s_io list is exhausted. */ static void requeue_io(struct inode *inode) { list_move(&inode->i_list, &inode->i_sb->s_more_io); } static void inode_sync_complete(struct inode *inode) { /* * Prevent speculative execution through spin_unlock(&inode_lock); */ smp_mb(); wake_up_bit(&inode->i_state, __I_SYNC); } /* * Move expired dirty inodes from @delaying_queue to @dispatch_queue. */ static void move_expired_inodes(struct list_head *delaying_queue, struct list_head *dispatch_queue, unsigned long *older_than_this) { while (!list_empty(delaying_queue)) { struct inode *inode = list_entry(delaying_queue->prev, struct inode, i_list); if (older_than_this && time_after(inode->dirtied_when, *older_than_this)) break; list_move(&inode->i_list, dispatch_queue); } } /* * Queue all expired dirty inodes for io, eldest first. */ static void queue_io(struct super_block *sb, unsigned long *older_than_this) { list_splice_init(&sb->s_more_io, sb->s_io.prev); move_expired_inodes(&sb->s_dirty, &sb->s_io, older_than_this); } int sb_has_dirty_inodes(struct super_block *sb) { return !list_empty(&sb->s_dirty) || !list_empty(&sb->s_io) || !list_empty(&sb->s_more_io); } EXPORT_SYMBOL(sb_has_dirty_inodes); /* * Write a single inode's dirty pages and inode data out to disk. * If `wait' is set, wait on the writeout. * * The whole writeout design is quite complex and fragile. We want to avoid * starvation of particular inodes when others are being redirtied, prevent * livelocks, etc. * * Called under inode_lock. */ static int __sync_single_inode(struct inode *inode, struct writeback_control *wbc) { unsigned dirty; struct address_space *mapping = inode->i_mapping; int wait = wbc->sync_mode == WB_SYNC_ALL; int ret; BUG_ON(inode->i_state & I_SYNC); /* Set I_SYNC, reset I_DIRTY */ dirty = inode->i_state & I_DIRTY; inode->i_state |= I_SYNC; inode->i_state &= ~I_DIRTY; spin_unlock(&inode_lock); ret = do_writepages(mapping, wbc); /* Don't write the inode if only I_DIRTY_PAGES was set */ if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { int err = write_inode(inode, wait); if (ret == 0) ret = err; } if (wait) { int err = filemap_fdatawait(mapping); if (ret == 0) ret = err; } spin_lock(&inode_lock); inode->i_state &= ~I_SYNC; if (!(inode->i_state & I_FREEING)) { if (!(inode->i_state & I_DIRTY) && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { /* * We didn't write back all the pages. nfs_writepages() * sometimes bales out without doing anything. Redirty * the inode; Move it from s_io onto s_more_io/s_dirty. */ /* * akpm: if the caller was the kupdate function we put * this inode at the head of s_dirty so it gets first * consideration. Otherwise, move it to the tail, for * the reasons described there. I'm not really sure * how much sense this makes. Presumably I had a good * reasons for doing it this way, and I'd rather not * muck with it at present. */ if (wbc->for_kupdate) { /* * For the kupdate function we move the inode * to s_more_io so it will get more writeout as * soon as the queue becomes uncongested. */ inode->i_state |= I_DIRTY_PAGES; if (wbc->nr_to_write <= 0) { /* * slice used up: queue for next turn */ requeue_io(inode); } else { /* * somehow blocked: retry later */ redirty_tail(inode); } } else { /* * Otherwise fully redirty the inode so that * other inodes on this superblock will get some * writeout. Otherwise heavy writing to one * file would indefinitely suspend writeout of * all the other files. */ inode->i_state |= I_DIRTY_PAGES; redirty_tail(inode); } } else if (inode->i_state & I_DIRTY) { /* * Someone redirtied the inode while were writing back * the pages. */ redirty_tail(inode); } else if (atomic_read(&inode->i_count)) { /* * The inode is clean, inuse */ list_move(&inode->i_list, &inode_in_use); } else { /* * The inode is clean, unused */ list_move(&inode->i_list, &inode_unused); } } inode_sync_complete(inode); return ret; } /* * Write out an inode's dirty pages. Called under inode_lock. Either the * caller has ref on the inode (either via __iget or via syscall against an fd) * or the inode has I_WILL_FREE set (via generic_forget_inode) */ static int __writeback_single_inode(struct inode *inode, struct writeback_control *wbc) { wait_queue_head_t *wqh; if (!atomic_read(&inode->i_count)) WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING))); else WARN_ON(inode->i_state & I_WILL_FREE); if ((wbc->sync_mode != WB_SYNC_ALL) && (inode->i_state & I_SYNC)) { /* * We're skipping this inode because it's locked, and we're not * doing writeback-for-data-integrity. Move it to s_more_io so * that writeback can proceed with the other inodes on s_io. * We'll have another go at writing back this inode when we * completed a full scan of s_io. */ requeue_io(inode); return 0; } /* * It's a data-integrity sync. We must wait. */ if (inode->i_state & I_SYNC) { DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC); wqh = bit_waitqueue(&inode->i_state, __I_SYNC); do { spin_unlock(&inode_lock); __wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE); spin_lock(&inode_lock); } while (inode->i_state & I_SYNC); } return __sync_single_inode(inode, wbc); } /* * Write out a superblock's list of dirty inodes. A wait will be performed * upon no inodes, all inodes or the final one, depending upon sync_mode. * * If older_than_this is non-NULL, then only write out inodes which * had their first dirtying at a time earlier than *older_than_this. * * If we're a pdlfush thread, then implement pdflush collision avoidance * against the entire list. * * WB_SYNC_HOLD is a hack for sys_sync(): reattach the inode to sb->s_dirty so * that it can be located for waiting on in __writeback_single_inode(). * * If `bdi' is non-zero then we're being asked to writeback a specific queue. * This function assumes that the blockdev superblock's inodes are backed by * a variety of queues, so all inodes are searched. For other superblocks, * assume that all inodes are backed by the same queue. * * FIXME: this linear search could get expensive with many fileystems. But * how to fix? We need to go from an address_space to all inodes which share * a queue with that address_space. (Easy: have a global "dirty superblocks" * list). * * The inodes to be written are parked on sb->s_io. They are moved back onto * sb->s_dirty as they are selected for writing. This way, none can be missed * on the writer throttling path, and we get decent balancing between many * throttled threads: we don't want them all piling up on inode_sync_wait. */ void generic_sync_sb_inodes(struct super_block *sb, struct writeback_control *wbc) { const unsigned long start = jiffies; /* livelock avoidance */ spin_lock(&inode_lock);


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