Hi,
As you said, I will resend a patch. Thanks for your review.
On Thu, Nov 27, 2014 at 08:24:21PM -0800, Jaegeuk Kim wrote:
> Hi,
>
> On Thu, Nov 27, 2014 at 06:11:51PM +0900, Changman Lee wrote:
> > If there are many inodes that have data blocks in victim segment,
> > it takes long time to find a inode in gc_inode list.
> > Let's use radix_tree to reduce lookup time.
> >
> > Signed-off-by: Changman Lee <cm224.lee@xxxxxxxxxxx>
> > ---
> > fs/f2fs/gc.c | 21 ++++++++++++++-------
> > 1 file changed, 14 insertions(+), 7 deletions(-)
> >
> > diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> > index 29fc7e5..fc765c1 100644
> > --- a/fs/f2fs/gc.c
> > +++ b/fs/f2fs/gc.c
> > @@ -24,6 +24,7 @@
> > #include "gc.h"
> > #include <trace/events/f2fs.h>
> >
> > +RADIX_TREE(gc_inode_root, GFP_ATOMIC);
>
> How about adding a radix tree locally along with ilist?
>
> > static struct kmem_cache *winode_slab;
> >
> > static int gc_thread_func(void *data)
> > @@ -338,13 +339,13 @@ static const struct victim_selection default_v_ops = {
> > .get_victim = get_victim_by_default,
> > };
> >
> > -static struct inode *find_gc_inode(nid_t ino, struct list_head *ilist)
> > +static struct inode *find_gc_inode(nid_t ino)
> > {
> > struct inode_entry *ie;
> >
> > - list_for_each_entry(ie, ilist, list)
> > - if (ie->inode->i_ino == ino)
> > - return ie->inode;
> > + ie = radix_tree_lookup(&gc_inode_root, ino);
> > + if (ie)
> > + return ie->inode;
> > return NULL;
> > }
> >
> > @@ -352,13 +353,19 @@ static void add_gc_inode(struct inode *inode, struct list_head *ilist)
> > {
> > struct inode_entry *new_ie;
> >
> > - if (inode == find_gc_inode(inode->i_ino, ilist)) {
> > + new_ie = radix_tree_lookup(&gc_inode_root, inode->i_ino);
> > + if (new_ie) {
> > iput(inode);
> > return;
> > }
> >
> > new_ie = f2fs_kmem_cache_alloc(winode_slab, GFP_NOFS);
> > new_ie->inode = inode;
> > +
> > + if (radix_tree_insert(&gc_inode_root, inode->i_ino, new_ie)) {
> > + kmem_cache_free(winode_slab, new_ie);
> > + return;
> > + }
>
> The add_gc_inode should succeed all the tiem.
> It seems that we need a sort of loop to avoid that.
>
> > list_add_tail(&new_ie->list, ilist);
> > }
> >
> > @@ -367,7 +374,7 @@ static void put_gc_inode(struct list_head *ilist)
> > struct inode_entry *ie, *next_ie;
> > list_for_each_entry_safe(ie, next_ie, ilist, list) {
> > iput(ie->inode);
> > - list_del(&ie->list);
>
> Logically, it'd better remain list_del.
>
> > + radix_tree_delete(&gc_inode_root, ie->inode->i_ino);
>
> We should not use ie->inode, since it was already put.
>
> > kmem_cache_free(winode_slab, ie);
> > }
> > }
> > @@ -614,7 +621,7 @@ next_step:
> > }
> >
> > /* phase 3 */
> > - inode = find_gc_inode(dni.ino, ilist);
> > + inode = find_gc_inode(dni.ino);
>
> It needs to pass a local radix tree pointer.
>
> > if (inode) {
> > start_bidx = start_bidx_of_node(nofs,
> > F2FS_I(inode));
> > --
> > 1.9.1
> >
> >
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