Subject: [to-be-updated] aio-reqs_active-reqs_available.patch removed from -mm tree To: koverstreet@xxxxxxxxxx,asamymuthupa@xxxxxxxxxx,axboe@xxxxxxxxx,balbi@xxxxxx,bcrl@xxxxxxxxx,gregkh@xxxxxxxxxxxxxxxxxxx,jlbec@xxxxxxxxxxxx,jmoyer@xxxxxxxxxx,mfasheh@xxxxxxxx,rusty@xxxxxxxxxxxxxxx,sbradshaw@xxxxxxxxxx,smani@xxxxxxxxxx,tytso@xxxxxxx,viro@xxxxxxxxxxxxxxxxxx,zab@xxxxxxxxxx,mm-commits@xxxxxxxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Thu, 23 May 2013 13:50:22 -0700 The patch titled Subject: aio: reqs_active -> reqs_available has been removed from the -mm tree. Its filename was aio-reqs_active-reqs_available.patch This patch was dropped because an updated version will be merged ------------------------------------------------------ From: Kent Overstreet <koverstreet@xxxxxxxxxx> Subject: aio: reqs_active -> reqs_available The number of outstanding kiocbs is one of the few shared things left that has to be touched for every kiocb - it'd be nice to make it percpu. We can make it per cpu by treating it like an allocation problem: we have a maximum number of kiocbs that can be outstanding (i.e. slots) - then we just allocate and free slots, and we know how to write per cpu allocators. So as prep work for that, we convert reqs_active to reqs_available. Signed-off-by: Kent Overstreet <koverstreet@xxxxxxxxxx> Cc: Zach Brown <zab@xxxxxxxxxx> Cc: Felipe Balbi <balbi@xxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: Mark Fasheh <mfasheh@xxxxxxxx> Cc: Joel Becker <jlbec@xxxxxxxxxxxx> Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx> Cc: Jens Axboe <axboe@xxxxxxxxx> Cc: Asai Thambi S P <asamymuthupa@xxxxxxxxxx> Cc: Selvan Mani <smani@xxxxxxxxxx> Cc: Sam Bradshaw <sbradshaw@xxxxxxxxxx> Cc: Jeff Moyer <jmoyer@xxxxxxxxxx> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Benjamin LaHaise <bcrl@xxxxxxxxx> Reviewed-by: "Theodore Ts'o" <tytso@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/aio.c | 33 +++++++++++++++++++-------------- 1 file changed, 19 insertions(+), 14 deletions(-) diff -puN fs/aio.c~aio-reqs_active-reqs_available fs/aio.c --- a/fs/aio.c~aio-reqs_active-reqs_available +++ a/fs/aio.c @@ -89,7 +89,13 @@ struct kioctx { struct work_struct rcu_work; struct { - atomic_t reqs_active; + /* + * This counts the number of available slots in the ringbuffer, + * so we avoid overflowing it: it's decremented (if positive) + * when allocating a kiocb and incremented when the resulting + * io_event is pulled off the ringbuffer. + */ + atomic_t reqs_available; } ____cacheline_aligned_in_smp; struct { @@ -306,17 +312,17 @@ static void free_ioctx(struct kioctx *ct head = ring->head; kunmap_atomic(ring); - while (atomic_read(&ctx->reqs_active) > 0) { + while (atomic_read(&ctx->reqs_available) < ctx->nr_events - 1) { wait_event(ctx->wait, head != ctx->tail); avail = (head <= ctx->tail ? ctx->tail : ctx->nr_events) - head; - atomic_sub(avail, &ctx->reqs_active); + atomic_add(avail, &ctx->reqs_available); head += avail; head %= ctx->nr_events; } - WARN_ON(atomic_read(&ctx->reqs_active) < 0); + WARN_ON(atomic_read(&ctx->reqs_available) > ctx->nr_events - 1); aio_free_ring(ctx); @@ -380,6 +386,8 @@ static struct kioctx *ioctx_alloc(unsign if (aio_setup_ring(ctx) < 0) goto out_freectx; + atomic_set(&ctx->reqs_available, ctx->nr_events - 1); + /* limit the number of system wide aios */ spin_lock(&aio_nr_lock); if (aio_nr + nr_events > aio_max_nr || @@ -482,7 +490,7 @@ void exit_aio(struct mm_struct *mm) "exit_aio:ioctx still alive: %d %d %d\n", atomic_read(&ctx->users), atomic_read(&ctx->dead), - atomic_read(&ctx->reqs_active)); + atomic_read(&ctx->reqs_available)); /* * We don't need to bother with munmap() here - * exit_mmap(mm) is coming and it'll unmap everything. @@ -514,12 +522,9 @@ static inline struct kiocb *aio_get_req( { struct kiocb *req; - if (atomic_read(&ctx->reqs_active) >= ctx->nr_events) + if (atomic_dec_if_positive(&ctx->reqs_available) <= 0) return NULL; - if (atomic_inc_return(&ctx->reqs_active) > ctx->nr_events - 1) - goto out_put; - req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL|__GFP_ZERO); if (unlikely(!req)) goto out_put; @@ -529,7 +534,7 @@ static inline struct kiocb *aio_get_req( return req; out_put: - atomic_dec(&ctx->reqs_active); + atomic_inc(&ctx->reqs_available); return NULL; } @@ -600,7 +605,7 @@ void aio_complete(struct kiocb *iocb, lo /* * Take rcu_read_lock() in case the kioctx is being destroyed, as we - * need to issue a wakeup after decrementing reqs_active. + * need to issue a wakeup after incrementing reqs_available. */ rcu_read_lock(); @@ -618,7 +623,7 @@ void aio_complete(struct kiocb *iocb, lo */ if (unlikely(xchg(&iocb->ki_cancel, KIOCB_CANCELLED) == KIOCB_CANCELLED)) { - atomic_dec(&ctx->reqs_active); + atomic_inc(&ctx->reqs_available); /* Still need the wake_up in case free_ioctx is waiting */ goto put_rq; } @@ -756,7 +761,7 @@ static long aio_read_events_ring(struct pr_debug("%li h%u t%u\n", ret, head, ctx->tail); - atomic_sub(ret, &ctx->reqs_active); + atomic_add(ret, &ctx->reqs_available); out: mutex_unlock(&ctx->ring_lock); @@ -1140,7 +1145,7 @@ static int io_submit_one(struct kioctx * aio_put_req(req); /* drop extra ref to req */ return 0; out_put_req: - atomic_dec(&ctx->reqs_active); + atomic_inc(&ctx->reqs_available); aio_put_req(req); /* drop extra ref to req */ aio_put_req(req); /* drop i/o ref to req */ return ret; _ Patches currently in -mm which might be from koverstreet@xxxxxxxxxx are linux-next.patch aio-percpu-reqs_available.patch generic-dynamic-per-cpu-refcounting.patch aio-percpu-ioctx-refcount.patch aio-use-xchg-instead-of-completion_lock.patch block-prep-work-for-batch-completion.patch block-aio-batch-completion-for-bios-kiocbs.patch aio-fix-kioctx-not-being-freed-after-cancellation-at-exit-time.patch block-aio-batch-completion-for-bios-kiocbs-fix.patch virtio-blk-convert-to-batch-completion.patch mtip32xx-convert-to-batch-completion.patch aio-convert-the-ioctx-list-to-radix-tree.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html