* + aio-use-call_rcu-instead-of-synchronize_rcu-in-kill_ioctx.patch added to -mm tree
@ 2013-05-31 19:40 akpm
0 siblings, 0 replies; only message in thread
From: akpm @ 2013-05-31 19:40 UTC (permalink / raw)
To: mm-commits, zab, viro, smani, sbradshaw, rusty, mfasheh, jmoyer,
jlbec, gregkh, bcrl, balbi, axboe, asamymuthupa, koverstreet
Subject: + aio-use-call_rcu-instead-of-synchronize_rcu-in-kill_ioctx.patch added to -mm tree
To: koverstreet@google.com,asamymuthupa@micron.com,axboe@kernel.dk,balbi@ti.com,bcrl@kvack.org,gregkh@linuxfoundation.org,jlbec@evilplan.org,jmoyer@redhat.com,mfasheh@suse.com,rusty@rustcorp.com.au,sbradshaw@micron.com,smani@micron.com,viro@zeniv.linux.org.uk,zab@redhat.com
From: akpm@linux-foundation.org
Date: Fri, 31 May 2013 12:40:53 -0700
The patch titled
Subject: aio: Use call_rcu() instead of synchronize_rcu() in kill_ioctx()
has been added to the -mm tree. Its filename is
aio-use-call_rcu-instead-of-synchronize_rcu-in-kill_ioctx.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Kent Overstreet <koverstreet@google.com>
Subject: aio: Use call_rcu() instead of synchronize_rcu() in kill_ioctx()
Just making ioctx shutdown asynchronous so as not to block io_destroy()
- and percpu refcounts for the ioctx are going to need a RCU barrier in
the same place anyways.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
Cc: Zach Brown <zab@redhat.com>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Tested-by: Jens Axboe <axboe@kernel.dk>
Cc: Asai Thambi S P <asamymuthupa@micron.com>
Cc: Selvan Mani <smani@micron.com>
Cc: Sam Bradshaw <sbradshaw@micron.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Tested-by: Benjamin LaHaise <bcrl@kvack.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
fs/aio.c | 36 ++++++++++++++++--------------------
1 file changed, 16 insertions(+), 20 deletions(-)
diff -puN fs/aio.c~aio-use-call_rcu-instead-of-synchronize_rcu-in-kill_ioctx fs/aio.c
--- a/fs/aio.c~aio-use-call_rcu-instead-of-synchronize_rcu-in-kill_ioctx
+++ a/fs/aio.c
@@ -141,9 +141,6 @@ static void aio_free_ring(struct kioctx
for (i = 0; i < ctx->nr_pages; i++)
put_page(ctx->ring_pages[i]);
- if (ctx->mmap_size)
- vm_munmap(ctx->mmap_base, ctx->mmap_size);
-
if (ctx->ring_pages && ctx->ring_pages != ctx->internal_pages)
kfree(ctx->ring_pages);
}
@@ -322,11 +319,6 @@ static void free_ioctx(struct kioctx *ct
aio_free_ring(ctx);
- spin_lock(&aio_nr_lock);
- BUG_ON(aio_nr - ctx->max_reqs > aio_nr);
- aio_nr -= ctx->max_reqs;
- spin_unlock(&aio_nr_lock);
-
pr_debug("freeing %p\n", ctx);
/*
@@ -435,17 +427,24 @@ static void kill_ioctx(struct kioctx *ct
{
if (!atomic_xchg(&ctx->dead, 1)) {
hlist_del_rcu(&ctx->list);
- /* Between hlist_del_rcu() and dropping the initial ref */
- synchronize_rcu();
/*
- * We can't punt to workqueue here because put_ioctx() ->
- * free_ioctx() will unmap the ringbuffer, and that has to be
- * done in the original process's context. kill_ioctx_rcu/work()
- * exist for exit_aio(), as in that path free_ioctx() won't do
- * the unmap.
+ * It'd be more correct to do this in free_ioctx(), after all
+ * the outstanding kiocbs have finished - but by then io_destroy
+ * has already returned, so io_setup() could potentially return
+ * -EAGAIN with no ioctxs actually in use (as far as userspace
+ * could tell).
*/
- kill_ioctx_work(&ctx->rcu_work);
+ spin_lock(&aio_nr_lock);
+ BUG_ON(aio_nr - ctx->max_reqs > aio_nr);
+ aio_nr -= ctx->max_reqs;
+ spin_unlock(&aio_nr_lock);
+
+ if (ctx->mmap_size)
+ vm_munmap(ctx->mmap_base, ctx->mmap_size);
+
+ /* Between hlist_del_rcu() and dropping the initial ref */
+ call_rcu(&ctx->rcu_head, kill_ioctx_rcu);
}
}
@@ -495,10 +494,7 @@ void exit_aio(struct mm_struct *mm)
*/
ctx->mmap_size = 0;
- if (!atomic_xchg(&ctx->dead, 1)) {
- hlist_del_rcu(&ctx->list);
- call_rcu(&ctx->rcu_head, kill_ioctx_rcu);
- }
+ kill_ioctx(ctx);
}
}
_
Patches currently in -mm which might be from koverstreet@google.com are
linux-next.patch
aio-use-call_rcu-instead-of-synchronize_rcu-in-kill_ioctx.patch
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2013-05-31 19:40 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2013-05-31 19:40 + aio-use-call_rcu-instead-of-synchronize_rcu-in-kill_ioctx.patch added to -mm tree akpm
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.