| Message ID | 1302612902-14113-1-git-send-email-josef@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 04/12/2011 08:55 PM, Josef Bacik wrote: > Everytime we try to allocate disk space we try and see if we can pre-emptively > allocate a chunk, but in the common case we don't allocate anything, so there is > no sense in taking the chunk_mutex at all. So instead if we are allocating a > chunk, mark it in the space_info so we don't get two people trying to allocate > at the same time. Thanks, > Reviewed-by: Liu Bo <liubo2009@cn.fujitsu.com> > Signed-off-by: Josef Bacik <josef@redhat.com> > --- > V1->V2: Return in the case where we don't need to allocate a chunk instead of > going to out. > > fs/btrfs/ctree.h | 5 +++-- > fs/btrfs/extent-tree.c | 29 ++++++++++++++++++++++++----- > 2 files changed, 27 insertions(+), 7 deletions(-) > > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h > index 0d00a07..a566780 100644 > --- a/fs/btrfs/ctree.h > +++ b/fs/btrfs/ctree.h > @@ -740,10 +740,11 @@ struct btrfs_space_info { > */ > unsigned long reservation_progress; > > - int full; /* indicates that we cannot allocate any more > + int full:1; /* indicates that we cannot allocate any more > chunks for this space */ > - int force_alloc; /* set if we need to force a chunk alloc for > + int force_alloc:1; /* set if we need to force a chunk alloc for > this space */ > + int chunk_alloc:1; /* set if we are allocating a chunk */ > > struct list_head list; > > diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c > index f619c3c..362cc9b 100644 > --- a/fs/btrfs/extent-tree.c > +++ b/fs/btrfs/extent-tree.c > @@ -3020,6 +3020,7 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags, > found->bytes_may_use = 0; > found->full = 0; > found->force_alloc = 0; > + found->chunk_alloc = 0; > *space_info = found; > list_add_rcu(&found->list, &info->space_info); > atomic_set(&found->caching_threads, 0); > @@ -3273,10 +3274,9 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans, > { > struct btrfs_space_info *space_info; > struct btrfs_fs_info *fs_info = extent_root->fs_info; > + int wait_for_alloc = 0; > int ret = 0; > > - mutex_lock(&fs_info->chunk_mutex); > - > flags = btrfs_reduce_alloc_profile(extent_root, flags); > > space_info = __find_space_info(extent_root->fs_info, flags); > @@ -3287,21 +3287,40 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans, > } > BUG_ON(!space_info); > > +again: > spin_lock(&space_info->lock); > if (space_info->force_alloc) > force = 1; > if (space_info->full) { > spin_unlock(&space_info->lock); > - goto out; > + return 0; > } > > if (!force && !should_alloc_chunk(extent_root, space_info, > alloc_bytes)) { > spin_unlock(&space_info->lock); > - goto out; > + return 0; > + } else if (space_info->chunk_alloc) { > + wait_for_alloc = 1; > + } else { > + space_info->chunk_alloc = 1; > } > spin_unlock(&space_info->lock); > > + mutex_lock(&fs_info->chunk_mutex); > + > + /* > + * The chunk_mutex is held throughout the entirety of a chunk > + * allocation, so once we've acquired the chunk_mutex we know that the > + * other guy is done and we need to recheck and see if we should > + * allocate. > + */ > + if (wait_for_alloc) { > + mutex_unlock(&fs_info->chunk_mutex); > + wait_for_alloc = 0; > + goto again; > + } > + > /* > * If we have mixed data/metadata chunks we want to make sure we keep > * allocating mixed chunks instead of individual chunks. > @@ -3327,9 +3346,9 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans, > space_info->full = 1; > else > ret = 1; > + space_info->chunk_alloc = 0; > space_info->force_alloc = 0; > spin_unlock(&space_info->lock); > -out: > mutex_unlock(&extent_root->fs_info->chunk_mutex); > return ret; > } -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 0d00a07..a566780 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -740,10 +740,11 @@ struct btrfs_space_info { */ unsigned long reservation_progress; - int full; /* indicates that we cannot allocate any more + int full:1; /* indicates that we cannot allocate any more chunks for this space */ - int force_alloc; /* set if we need to force a chunk alloc for + int force_alloc:1; /* set if we need to force a chunk alloc for this space */ + int chunk_alloc:1; /* set if we are allocating a chunk */ struct list_head list; diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index f619c3c..362cc9b 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -3020,6 +3020,7 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags, found->bytes_may_use = 0; found->full = 0; found->force_alloc = 0; + found->chunk_alloc = 0; *space_info = found; list_add_rcu(&found->list, &info->space_info); atomic_set(&found->caching_threads, 0); @@ -3273,10 +3274,9 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans, { struct btrfs_space_info *space_info; struct btrfs_fs_info *fs_info = extent_root->fs_info; + int wait_for_alloc = 0; int ret = 0; - mutex_lock(&fs_info->chunk_mutex); - flags = btrfs_reduce_alloc_profile(extent_root, flags); space_info = __find_space_info(extent_root->fs_info, flags); @@ -3287,21 +3287,40 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans, } BUG_ON(!space_info); +again: spin_lock(&space_info->lock); if (space_info->force_alloc) force = 1; if (space_info->full) { spin_unlock(&space_info->lock); - goto out; + return 0; } if (!force && !should_alloc_chunk(extent_root, space_info, alloc_bytes)) { spin_unlock(&space_info->lock); - goto out; + return 0; + } else if (space_info->chunk_alloc) { + wait_for_alloc = 1; + } else { + space_info->chunk_alloc = 1; } spin_unlock(&space_info->lock); + mutex_lock(&fs_info->chunk_mutex); + + /* + * The chunk_mutex is held throughout the entirety of a chunk + * allocation, so once we've acquired the chunk_mutex we know that the + * other guy is done and we need to recheck and see if we should + * allocate. + */ + if (wait_for_alloc) { + mutex_unlock(&fs_info->chunk_mutex); + wait_for_alloc = 0; + goto again; + } + /* * If we have mixed data/metadata chunks we want to make sure we keep * allocating mixed chunks instead of individual chunks. @@ -3327,9 +3346,9 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans, space_info->full = 1; else ret = 1; + space_info->chunk_alloc = 0; space_info->force_alloc = 0; spin_unlock(&space_info->lock); -out: mutex_unlock(&extent_root->fs_info->chunk_mutex); return ret; }
Everytime we try to allocate disk space we try and see if we can pre-emptively allocate a chunk, but in the common case we don't allocate anything, so there is no sense in taking the chunk_mutex at all. So instead if we are allocating a chunk, mark it in the space_info so we don't get two people trying to allocate at the same time. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com> --- V1->V2: Return in the case where we don't need to allocate a chunk instead of going to out. fs/btrfs/ctree.h | 5 +++-- fs/btrfs/extent-tree.c | 29 ++++++++++++++++++++++++----- 2 files changed, 27 insertions(+), 7 deletions(-)