From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
To: Emanuele Giuseppe Esposito <eesposit@redhat.com>, qemu-block@nongnu.org
Cc: John Snow <jsnow@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>,
Kevin Wolf <kwolf@redhat.com>, Max Reitz <mreitz@redhat.com>,
qemu-devel@nongnu.org
Subject: Re: [RFC PATCH 1/3] block-copy: improve documentation for BlockCopyTask type and functions
Date: Tue, 20 Apr 2021 15:03:08 +0300 [thread overview]
Message-ID: <9576b9d5-c40b-14d4-399f-4d14473433bb@virtuozzo.com> (raw)
In-Reply-To: <20210420100416.30713-2-eesposit@redhat.com>
20.04.2021 13:04, Emanuele Giuseppe Esposito wrote:
> As done in BlockCopyCallState, categorize BlockCopyTask
> in IN, State and OUT fields. This is just to understand
> which field has to be protected with a lock.
>
> Also add coroutine_fn attribute to block_copy_task_create,
> because it is only usedn block_copy_dirty_clusters, a coroutine
> function itself.
>
> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
> ---
> block/block-copy.c | 15 +++++++++++----
> 1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/block/block-copy.c b/block/block-copy.c
> index 39ae481c8b..03df50a354 100644
> --- a/block/block-copy.c
> +++ b/block/block-copy.c
> @@ -48,25 +48,32 @@ typedef struct BlockCopyCallState {
> QLIST_ENTRY(BlockCopyCallState) list;
>
> /* State */
> - int ret;
> bool finished;
> QemuCoSleepState *sleep_state;
> bool cancelled;
>
> /* OUT parameters */
> + int ret;
Hmm. Somehow, ret may be considered is part of state too.. But I don't really care. Here it looks not bad. Will see how and what you are going protect by new lock.
Note, that ret is concurently set in block_copy_task_entry..
> bool error_is_read;
> } BlockCopyCallState;
>
> typedef struct BlockCopyTask {
> + /* IN parameters. Initialized in block_copy_task_create()
> + * and never changed.
> + */
It's wrong about task field, as it has "ret" inside.
> AioTask task;
> -
> BlockCopyState *s;
> BlockCopyCallState *call_state;
> +
> + /* State */
> int64_t offset;
I think, offset is never changed after block_copy_task_create()..
> int64_t bytes;
> bool zeroes;
> - QLIST_ENTRY(BlockCopyTask) list;
> CoQueue wait_queue; /* coroutines blocked on this task */
> +
> + /* To reference all call states from BlockCopyTask */
Amm.. Actually,
To reference all tasks from BlockCopyState
> + QLIST_ENTRY(BlockCopyTask) list;
> +
> } BlockCopyTask;
>
> static int64_t task_end(BlockCopyTask *task)
> @@ -153,7 +160,7 @@ static bool coroutine_fn block_copy_wait_one(BlockCopyState *s, int64_t offset,
> * Search for the first dirty area in offset/bytes range and create task at
> * the beginning of it.
> */
> -static BlockCopyTask *block_copy_task_create(BlockCopyState *s,
> +static BlockCopyTask *coroutine_fn block_copy_task_create(BlockCopyState *s,
> BlockCopyCallState *call_state,
> int64_t offset, int64_t bytes)
> {
>
We mark by "coroutine_fn" functions that can be called _only_ from coroutine context. block_copy_task_create() may be called from any context, both coroutine and non-coroutine. So, it shouldn't have this mark.
--
Best regards,
Vladimir
next prev parent reply other threads:[~2021-04-20 12:05 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-20 10:04 [RFC PATCH 0/3] block-copy: lock tasks and calls list Emanuele Giuseppe Esposito
2021-04-20 10:04 ` [RFC PATCH 1/3] block-copy: improve documentation for BlockCopyTask type and functions Emanuele Giuseppe Esposito
2021-04-20 12:03 ` Vladimir Sementsov-Ogievskiy [this message]
2021-04-20 12:51 ` Emanuele Giuseppe Esposito
2021-04-20 13:11 ` Vladimir Sementsov-Ogievskiy
2021-04-20 10:04 ` [RFC PATCH 2/3] block-copy: add a CoMutex to the BlockCopyTask list Emanuele Giuseppe Esposito
2021-04-20 10:04 ` [RFC PATCH 3/3] block-copy: add CoMutex lock for BlockCopyCallState list Emanuele Giuseppe Esposito
2021-04-20 13:12 ` [RFC PATCH 0/3] block-copy: lock tasks and calls list Vladimir Sementsov-Ogievskiy
2021-04-21 8:38 ` Paolo Bonzini
2021-04-21 8:53 ` Vladimir Sementsov-Ogievskiy
2021-04-21 12:13 ` Paolo Bonzini
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