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>
Cc: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/aio.c | 27 +++++++++++++--------------
1 file changed, 13 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
@@ -82,7 +82,7 @@ struct kioctx {
struct work_struct rcu_work;
struct {
- atomic_t reqs_active;
+ atomic_t reqs_available;
} ____cacheline_aligned_in_smp;
struct {
@@ -299,17 +299,17 @@ 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) {
wait_event(ctx->wait, head != ctx->tail);
avail = (head < ctx->tail ? ctx->tail : ctx->nr) - head;
- atomic_sub(avail, &ctx->reqs_active);
+ atomic_add(avail, &ctx->reqs_available);
head += avail;
head %= ctx->nr;
}
- WARN_ON(atomic_read(&ctx->reqs_active) < 0);
+ WARN_ON(atomic_read(&ctx->reqs_available) > ctx->nr);
aio_free_ring(ctx);
@@ -373,6 +373,8 @@ static struct kioctx *ioctx_alloc(unsign
if (aio_setup_ring(ctx) < 0)
goto out_freectx;
+ atomic_set(&ctx->reqs_available, ctx->nr);
+
/* limit the number of system wide aios */
spin_lock(&aio_nr_lock);
if (aio_nr + nr_events > aio_max_nr ||
@@ -475,7 +477,7 @@ 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.
@@ -507,12 +509,9 @@ static inline struct kiocb *aio_get_req(
{
struct kiocb *req;
- if (atomic_read(&ctx->reqs_active) >= ctx->nr)
+ if (atomic_dec_if_positive(&ctx->reqs_available) <= 0)
return NULL;
- if (atomic_inc_return(&ctx->reqs_active) > ctx->nr)
- goto out_put;
-
req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL|__GFP_ZERO);
if (unlikely(!req))
goto out_put;
@@ -522,7 +521,7 @@ static inline struct kiocb *aio_get_req(
return req;
out_put:
- atomic_dec(&ctx->reqs_active);
+ atomic_inc(&ctx->reqs_available);
return NULL;
}
@@ -593,7 +592,7 @@ 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();
@@ -611,7 +610,7 @@ 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;
}
@@ -751,7 +750,7 @@ static int aio_read_events_ring(struct k
pr_debug("%d 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);
@@ -1170,7 +1169,7 @@ static int io_submit_one(struct kioctx *
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
aio-percpu-reqs_available.patch
generic-dynamic-per-cpu-refcounting.patch
aio-percpu-ioctx-refcount.patch
aio-use-xchg-instead-of-completion_lock.patch
aio-dont-include-aioh-in-schedh.patch
aio-kill-ki_key.patch
aio-kill-ki_retry.patch
block-aio-batch-completion-for-bios-kiocbs.patch
virtio-blk-convert-to-batch-completion.patch
mtip32xx-convert-to-batch-completion.patch
aio-fix-aio_read_events_ring-types.patch
aio-document-clarify-aio_read_events-and-shadow_tail.patch
aio-correct-calculation-of-available-events.patch
aio-v2-fix-kioctx-not-being-freed-after-cancellation-at-exit-time.patch
aio-fix-ringbuffer-calculation-so-we-dont-wrap.patch
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