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From: James Simmons <jsimmons@infradead.org>
To: lustre-devel@lists.lustre.org
Subject: [lustre-devel] [PATCH 11/22] lustre: llite: fix read if readahead window smaller than rpc size
Date: Tue,  2 Jun 2020 20:59:50 -0400
Message-ID: <1591146001-27171-12-git-send-email-jsimmons@infradead.org> (raw)
In-Reply-To: <1591146001-27171-1-git-send-email-jsimmons@infradead.org>

From: Wang Shilong <wshilong@ddn.com>

Readahead always try to align readahead with RPC size, but this
could introduce a problem if readahead window is smaller than RPC size.

With current codes, it will fallback a lot of 4k read because
RPC aligned window start plus window pages will be behind of
current read. Fix this to align with readahead window rather
than RPC size in this case.

WC-bug-id: https://jira.whamcloud.com/browse/LU-13412
Lustre-commit: 33d08805f27bb ("LU-13412 llite: fix read if readahead window smaller than rpc size")
Signed-off-by: Wang Shilong <wshilong@ddn.com>
Reviewed-on: https://review.whamcloud.com/38132
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Gu Zheng <gzheng@ddn.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
---
 fs/lustre/llite/rw.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/lustre/llite/rw.c b/fs/lustre/llite/rw.c
index fd0bed6..ff8f3c6 100644
--- a/fs/lustre/llite/rw.c
+++ b/fs/lustre/llite/rw.c
@@ -350,7 +350,11 @@ static unsigned long ria_page_count(struct ra_io_arg *ria)
 
 static pgoff_t ras_align(struct ll_readahead_state *ras, pgoff_t index)
 {
-	return index - (index % ras->ras_rpc_pages);
+	unsigned opt_size = min(ras->ras_window_pages, ras->ras_rpc_pages);
+
+	if (opt_size == 0)
+		opt_size = 1;
+	return index - (index % opt_size);
 }
 
 /* Check whether the index is in the defined ra-window */
-- 
1.8.3.1

  parent reply index

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-03  0:59 [lustre-devel] [PATCH 00/22] lustre: OpenSFS backport patches for May 29 2020 James Simmons
2020-06-03  0:59 ` [lustre-devel] [PATCH 01/22] lnet: libcfs: fix CPT handling for UP systems James Simmons
2020-06-03  0:59 ` [lustre-devel] [PATCH 02/22] lustre: use BIT() macro where appropriate in include James Simmons
2020-06-03  0:59 ` [lustre-devel] [PATCH 03/22] lustre: use BIT() macro where appropriate James Simmons
2020-06-03  0:59 ` [lustre-devel] [PATCH 04/22] lustre: ptlrpc: change LONG_UNLINK to PTLRPC_REQ_LONG_UNLINK James Simmons
2020-06-03  0:59 ` [lustre-devel] [PATCH 05/22] lustre: llite: use %pd to report dentry names James Simmons
2020-06-03  0:59 ` [lustre-devel] [PATCH 06/22] lnet: tidy lnet_discover and fix mem accounting bug James Simmons
2020-06-03  0:59 ` [lustre-devel] [PATCH 07/22] lustre: llite: prevent MAX_DIO_SIZE 32-bit truncation James Simmons
2020-06-03  0:59 ` [lustre-devel] [PATCH 08/22] lustre: llite: integrate statx() API with Lustre James Simmons
2020-06-03  0:59 ` [lustre-devel] [PATCH 09/22] lustre: ldlm: no current source if lu_ref_del not in same tsk James Simmons
2020-06-03  0:59 ` [lustre-devel] [PATCH 10/22] lnet: always pass struct lnet_md by reference James Simmons
2020-06-03  0:59 ` James Simmons [this message]
2020-06-03  0:59 ` [lustre-devel] [PATCH 12/22] lustre: obdclass: bind zombie export cleanup workqueue James Simmons
2020-06-03  0:59 ` [lustre-devel] [PATCH 13/22] lnet: handle discovery off properly James Simmons
2020-06-03  0:59 ` [lustre-devel] [PATCH 14/22] lnet: Force full discovery cycle James Simmons
2020-06-03  0:59 ` [lustre-devel] [PATCH 15/22] lnet: set route aliveness properly James Simmons
2020-06-03  0:59 ` [lustre-devel] [PATCH 16/22] lnet: Correct the default LND timeout James Simmons
2020-06-03  0:59 ` [lustre-devel] [PATCH 17/22] lnet: Add lnet_lnd_timeout to sysfs James Simmons
2020-06-03  0:59 ` [lustre-devel] [PATCH 18/22] lnet: lnd: Allow independent ko2iblnd timeout James Simmons
2020-06-03  0:59 ` [lustre-devel] [PATCH 19/22] lnet: lnd: Allow independent socklnd timeout James Simmons
2020-06-03  0:59 ` [lustre-devel] [PATCH 20/22] lnet: lnd: gracefully handle unexpected events James Simmons
2020-06-03  1:00 ` [lustre-devel] [PATCH 21/22] lustre: update version to 2.13.54 James Simmons
2020-06-03  1:00 ` [lustre-devel] [PATCH 22/22] lnet: procs: print new line based on distro James Simmons

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