/* * Copyright (C) 2007 Oracle. All rights reserved. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public * License v2 as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public * License along with this program; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 021110-1307, USA. */ #include #include "ctree.h" #include "disk-io.h" #include "print-tree.h" #include "transaction.h" #include "locking.h" /* * Defrag all the leaves in a given btree. * Read all the leaves and try to get key order to * better reflect disk order */ int btrfs_defrag_leaves(struct btrfs_trans_handle *trans, struct btrfs_root *root) { struct btrfs_path *path = NULL; struct btrfs_key key; int ret = 0; int wret; int level; int next_key_ret = 0; u64 last_ret = 0; u64 min_trans = 0; if (root->fs_info->extent_root == root) { /* * there's recursion here right now in the tree locking, * we can't defrag the extent root without deadlock */ goto out; } if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state)) goto out; path = btrfs_alloc_path(); if (!path) return -ENOMEM; level = btrfs_header_level(root->node); if (level == 0) goto out; if (root->defrag_progress.objectid == 0) { struct extent_buffer *root_node; u32 nritems; root_node = btrfs_lock_root_node(root); btrfs_set_lock_blocking(root_node); nritems = btrfs_header_nritems(root_node); root->defrag_max.objectid = 0; /* from above we know this is not a leaf */ btrfs_node_key_to_cpu(root_node, &root->defrag_max, nritems - 1); btrfs_tree_unlock(root_node); free_extent_buffer(root_node); memset(&key, 0, sizeof(key)); } else { memcpy(&key, &root->defrag_progress, sizeof(key)); } path->keep_locks = 1; ret = btrfs_search_forward(root, &key, path, min_trans); if (ret < 0) goto out; if (ret > 0) { ret = 0; goto out; } btrfs_release_path(path); /* * We don't need a lock on a leaf. btrfs_realloc_node() will lock all * leafs from path->nodes[1], so set lowest_level to 1 to avoid later * a deadlock (attempting to write lock an already write locked leaf). */ path->lowest_level = 1; wret = btrfs_search_slot(trans, root, &key, path, 0, 1); if (wret < 0) { ret = wret; goto out; } if (!path->nodes[1]) { ret = 0; goto out; } /* * The node at level 1 must always be locked when our path has * keep_locks set and lowest_level is 1, regardless of the value of * path->slots[1]. */ BUG_ON(path->locks[1] == 0); ret = btrfs_realloc_node(trans, root, path->nodes[1], 0, &last_ret, &root->defrag_progress); if (ret) { WARN_ON(ret == -EAGAIN); goto out; } /* * Now that we reallocated the node we can find the next key. Note that * btrfs_find_next_key() can release our path and do another search * without COWing, this is because even with path->keep_locks = 1, * btrfs_search_slot() / ctree.c:unlock_up() does not keeps a lock on a * node when path->slots[node_level - 1] does not point to the last * item or a slot beyond the last item (ctree.c:unlock_up()). Therefore * we search for the next key after reallocating our node. */ path->slots[1] = btrfs_header_nritems(path->nodes[1]); next_key_ret = btrfs_find_next_key(root, path, &key, 1, min_trans); if (next_key_ret == 0) { memcpy(&root->defrag_progress, &key, sizeof(key)); ret = -EAGAIN; } out: btrfs_free_path(path); if (ret == -EAGAIN) { if (root->defrag_max.objectid > root->defrag_progress.objectid) goto done; if (root->defrag_max.type > root->defrag_progress.type) goto done; if (root->defrag_max.offset > root->defrag_progress.offset) goto done; ret = 0; } done: if (ret != -EAGAIN) { memset(&root->defrag_progress, 0, sizeof(root->defrag_progress)); root->defrag_trans_start = trans->transid; } return ret; } on>mode:
authorSteven Rostedt (VMware) <rostedt@goodmis.org>2017-01-30 19:27:10 -0500
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2017-01-31 09:13:49 -0500
commit79c6f448c8b79c321e4a1f31f98194e4f6b6cae7 (patch)
tree370efda701f03cccf21e02bb1fdd3b852547d75c /sound/pci/lola/lola_clock.c
parent0c744ea4f77d72b3dcebb7a8f2684633ec79be88 (diff)
tracing: Fix hwlat kthread migration
The hwlat tracer creates a kernel thread at start of the tracer. It is pinned to a single CPU and will move to the next CPU after each period of running. If the user modifies the migration thread's affinity, it will not change after that happens. The original code created the thread at the first instance it was called, but later was changed to destroy the thread after the tracer was finished, and would not be created until the next instance of the tracer was established. The code that initialized the affinity was only called on the initial instantiation of the tracer. After that, it was not initialized, and the previous affinity did not match the current newly created one, making it appear that the user modified the thread's affinity when it did not, and the thread failed to migrate again. Cc: stable@vger.kernel.org Fixes: 0330f7aa8ee6 ("tracing: Have hwlat trace migrate across tracing_cpumask CPUs") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'sound/pci/lola/lola_clock.c')