On Tue, May 07, 2013 at 07:33:59PM +0900, Jaegeuk Kim wrote: > 2013-05-06 (월), 23:15 +0800, Haicheng Li: > > diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c > > index 1fe3fe2..3136224 100644 > > --- a/fs/f2fs/node.c > > +++ b/fs/f2fs/node.c > > @@ -1342,6 +1342,8 @@ static void build_free_nids(struct f2fs_sb_info *sbi) > > if (nid >= nm_i->max_nid) > > nid = 0; > > > > + if (nm_i->fcnt > 2 * MAX_FREE_NIDS) > > + break; > > Could you explain when this can happen? I'm thinking of this possible scenario: as we don't hold any spinlock to protect the context, add_free_nid() could be called by other thread anytime, e.g. by the gc_thread_func() in background. then nm_i->fcnt could be increased as 2 * MAX_FREE_NIDS while i < FREE_NID_PAGES. Anything I misconsidered? > IMO, this is an unnecessary condition check, since the below condition > that includes FREE_NID_PAGES already limits the number of free nids. > Thanks, hmm, the pros is that this check may possibly avoid some (< 4) unnecessary while-loop, the cons is that too many checks of (nm_i->fcnt > 2 * MAX_FREE_NIDS) would make the code looking messy and fragmentary... > > if (i++ == FREE_NID_PAGES) > > break; > > } > > -- > Jaegeuk Kim > Samsung -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
