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From: Jens Axboe <axboe@kernel.dk>
To: linux-fsdevel@vger.kernel.org, linux-aio@kvack.org,
	linux-block@vger.kernel.org
Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com,
	Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 17/17] io_uring: add io_uring_event cache hit information
Date: Fri, 18 Jan 2019 09:12:25 -0700	[thread overview]
Message-ID: <20190118161225.4545-18-axboe@kernel.dk> (raw)
In-Reply-To: <20190118161225.4545-1-axboe@kernel.dk>

Add hint on whether a read was served out of the page cache, or if it
hit media. This is useful for buffered async IO, O_DIRECT reads would
never have this set (for obvious reasons).

If the read hit page cache, cqe->flags will have IOCQE_FLAG_CACHEHIT
set.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 fs/io_uring.c                 | 7 ++++++-
 include/uapi/linux/io_uring.h | 5 +++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 4709a19d692b..aec7c3db32c5 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -542,11 +542,16 @@ static void io_fput(struct io_kiocb *req)
 static void io_complete_rw(struct kiocb *kiocb, long res, long res2)
 {
 	struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw);
+	unsigned ev_flags = 0;
 
 	kiocb_end_write(kiocb);
 
 	io_fput(req);
-	io_cqring_add_event(req->ctx, req->user_data, res, 0);
+
+	if (res > 0 && (req->flags & REQ_F_FORCE_NONBLOCK))
+		ev_flags = IOCQE_FLAG_CACHEHIT;
+
+	io_cqring_add_event(req->ctx, req->user_data, res, ev_flags);
 	io_free_req(req);
 }
 
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 60b52c551c87..3b8d623031ad 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -71,6 +71,11 @@ struct io_uring_cqe {
 	__u32	flags;
 };
 
+/*
+ * io_uring_event->flags
+ */
+#define IOCQE_FLAG_CACHEHIT	(1 << 0)	/* IO did not hit media */
+
 /*
  * Magic offsets for the application to mmap the data it needs
  */
-- 
2.17.1


      parent reply	other threads:[~2019-01-18 16:13 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-18 16:12 [PATCHSET v6] io_uring IO interface Jens Axboe
2019-01-18 16:12 ` [PATCH 01/17] fs: add an iopoll method to struct file_operations Jens Axboe
2019-01-18 16:12 ` [PATCH 02/17] block: wire up block device iopoll method Jens Axboe
2019-01-18 16:12 ` [PATCH 03/17] block: add bio_set_polled() helper Jens Axboe
2019-01-18 16:12 ` [PATCH 04/17] iomap: wire up the iopoll method Jens Axboe
2019-01-18 16:12 ` [PATCH 05/17] Add io_uring IO interface Jens Axboe
2019-01-21  9:13   ` Roman Penyaev
2019-01-21 15:30     ` Jens Axboe
2019-01-21 15:58       ` Roman Penyaev
2019-01-21 16:23         ` Jens Axboe
2019-01-21 16:49           ` Roman Penyaev
2019-01-22 16:11             ` Jens Axboe
2019-01-18 16:12 ` [PATCH 06/17] io_uring: add fsync support Jens Axboe
2019-01-18 16:12 ` [PATCH 07/17] io_uring: support for IO polling Jens Axboe
2019-01-18 16:12 ` [PATCH 08/17] fs: add fget_many() and fput_many() Jens Axboe
2019-01-18 16:12 ` [PATCH 09/17] io_uring: use fget/fput_many() for file references Jens Axboe
2019-01-18 16:12 ` [PATCH 10/17] io_uring: batch io_kiocb allocation Jens Axboe
2019-01-18 16:12 ` [PATCH 11/17] block: implement bio helper to add iter bvec pages to bio Jens Axboe
2019-01-18 16:12 ` [PATCH 12/17] io_uring: add support for pre-mapped user IO buffers Jens Axboe
2019-01-18 16:12 ` [PATCH 13/17] io_uring: add file set registration Jens Axboe
2019-01-18 16:12 ` [PATCH 14/17] io_uring: add submission polling Jens Axboe
2019-01-18 16:12 ` [PATCH 15/17] io_uring: add io_kiocb ref count Jens Axboe
2019-01-18 16:12 ` [PATCH 16/17] io_uring: add support for IORING_OP_POLL Jens Axboe
2019-01-18 16:12 ` Jens Axboe [this message]

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