From: Christoph Hellwig <[email protected]>
To: Jens Axboe <[email protected]>
Cc: [email protected], [email protected], [email protected],
[email protected], [email protected]
Subject: Re: [PATCH 6/6] iomap: support IOCB_DIO_DEFER
Date: Thu, 20 Jul 2023 06:59:19 +0200 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
> + if (dio->flags & IOMAP_DIO_DEFER_COMP) {
> + /* only polled IO cares about private cleared */
> + iocb->private = dio;
FYI, I find this comment a bit weird as it comments on what we're
not doing in a path where it is irreleant. I'd rather only clear
the private data in the path where polling is applicable and have
a comment there why it is cleared. That probably belongs into the
first patch restructuring the function.
> @@ -277,12 +308,15 @@ static loff_t iomap_dio_bio_iter(const struct iomap_iter *iter,
> * data IO that doesn't require any metadata updates (including
> * after IO completion such as unwritten extent conversion) and
> * the underlying device supports FUA. This allows us to avoid
> - * cache flushes on IO completion.
> + * cache flushes on IO completion. If we can't use FUA and
> + * need to sync, disable in-task completions.
... because iomap_dio_complete will have to call generic_write_sync to
do a blocking ->fsync call.
> @@ -308,6 +342,8 @@ static loff_t iomap_dio_bio_iter(const struct iomap_iter *iter,
> pad = pos & (fs_block_size - 1);
> if (pad)
> iomap_dio_zero(iter, dio, pos - pad, pad);
> +
> + dio->flags &= ~IOMAP_DIO_DEFER_COMP;
Why does zeroing disable the deferred completions? I can't really think
of why, which is probably a strong indicator why this needs a comment.
next prev parent reply other threads:[~2023-07-20 4:59 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-19 19:54 [PATCHSET v3 0/6] Improve async iomap DIO performance Jens Axboe
2023-07-19 19:54 ` [PATCH 1/6] iomap: cleanup up iomap_dio_bio_end_io() Jens Axboe
2023-07-20 4:50 ` Christoph Hellwig
2023-07-20 16:13 ` Jens Axboe
2023-07-19 19:54 ` [PATCH 2/6] iomap: add IOMAP_DIO_INLINE_COMP Jens Axboe
2023-07-20 4:51 ` Christoph Hellwig
2023-07-20 16:19 ` Jens Axboe
2023-07-19 19:54 ` [PATCH 3/6] iomap: treat a write through cache the same as FUA Jens Axboe
2023-07-20 4:54 ` Christoph Hellwig
2023-07-20 16:23 ` Jens Axboe
2023-07-19 19:54 ` [PATCH 4/6] fs: add IOCB flags related to passing back dio completions Jens Axboe
2023-07-20 5:01 ` Christoph Hellwig
2023-07-20 16:25 ` Jens Axboe
2023-07-19 19:54 ` [PATCH 5/6] io_uring/rw: add write support for IOCB_DIO_DEFER Jens Axboe
2023-07-19 19:54 ` [PATCH 6/6] iomap: support IOCB_DIO_DEFER Jens Axboe
2023-07-20 4:59 ` Christoph Hellwig [this message]
2023-07-20 16:27 ` Jens Axboe
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