On thu, 26 Dec 2013 18:22:10 +0800, Gu Zheng wrote: > Add a 'next_free' field into kioctx_table to store the next id that > may be free, in order to reduce the search region when we insert > kioctx into kioctx table. > When we take a free slot from kioctx_table, update 'next_free' to > the next slot. Also when we free one slot to kioctx_table, update 'next_free' > to the new free slot if it's smaller than 'next_free'. So that we can > ensure that the slots before 'next_free' are all used, and the search can > start > from 'next_free' to reduce the search and improve the performance. > > Signed-off-by: Gu Zheng <[email protected]>
Reviewed-by: Miao Xie <[email protected]> Thanks Miao > --- > fs/aio.c | 10 ++++++++-- > 1 files changed, 8 insertions(+), 2 deletions(-) > > diff --git a/fs/aio.c b/fs/aio.c > index 062a5f6..489fda6 100644 > --- a/fs/aio.c > +++ b/fs/aio.c > @@ -69,6 +69,7 @@ struct aio_ring { > struct kioctx_table { > struct rcu_head rcu; > unsigned nr; > + unsigned next_free; > struct kioctx *table[]; > }; > > @@ -548,11 +549,12 @@ static int ioctx_add_table(struct kioctx *ctx, struct > mm_struct *mm) > table = rcu_dereference(mm->ioctx_table); > > while (1) { > - if (table) > - for (i = 0; i < table->nr; i++) > + if (table && table->next_free < table->nr) > + for (i = table->next_free; i < table->nr; i++) > if (!table->table[i]) { > ctx->id = i; > table->table[i] = ctx; > + table->next_free = i + 1; > rcu_read_unlock(); > spin_unlock(&mm->ioctx_lock); > > @@ -579,8 +581,10 @@ static int ioctx_add_table(struct kioctx *ctx, struct > mm_struct *mm) > old = rcu_dereference(mm->ioctx_table); > > if (!old) { > + table->next_free = 0; > rcu_assign_pointer(mm->ioctx_table, table); > } else if (table->nr > old->nr) { > + table->next_free = old->nr; > memcpy(table->table, old->table, > old->nr * sizeof(struct kioctx *)); > > @@ -716,6 +720,8 @@ static void kill_ioctx(struct mm_struct *mm, struct > kioctx *ctx) > > WARN_ON(ctx != table->table[ctx->id]); > table->table[ctx->id] = NULL; > + if (ctx->id < table->next_free) > + table->next_free = ctx->id; > rcu_read_unlock(); > spin_unlock(&mm->ioctx_lock); > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
