From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Lin Feng <linf@wangsu.com>, Jan Kara <jack@suse.cz>,
Jens Axboe <axboe@kernel.dk>, Sasha Levin <sashal@kernel.org>,
linux-block@vger.kernel.org
Subject: [PATCH AUTOSEL 4.19 10/14] bfq-iosched: Revert "bfq: Fix computation of shallow depth"
Date: Mon, 8 Feb 2021 12:59:22 -0500 [thread overview]
Message-ID: <20210208175926.2092211-10-sashal@kernel.org> (raw)
In-Reply-To: <20210208175926.2092211-1-sashal@kernel.org>
From: Lin Feng <linf@wangsu.com>
[ Upstream commit 388c705b95f23f317fa43e6abf9ff07b583b721a ]
This reverts commit 6d4d273588378c65915acaf7b2ee74e9dd9c130a.
bfq.limit_depth passes word_depths[] as shallow_depth down to sbitmap core
sbitmap_get_shallow, which uses just the number to limit the scan depth of
each bitmap word, formula:
scan_percentage_for_each_word = shallow_depth / (1 << sbimap->shift) * 100%
That means the comments's percentiles 50%, 75%, 18%, 37% of bfq are correct.
But after commit patch 'bfq: Fix computation of shallow depth', we use
sbitmap.depth instead, as a example in following case:
sbitmap.depth = 256, map_nr = 4, shift = 6; sbitmap_word.depth = 64.
The resulsts of computed bfqd->word_depths[] are {128, 192, 48, 96}, and
three of the numbers exceed core dirver's 'sbitmap_word.depth=64' limit
nothing.
Signed-off-by: Lin Feng <linf@wangsu.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
block/bfq-iosched.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index b7ad8ac6bb41e..5198ed1b36690 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -5280,13 +5280,13 @@ static unsigned int bfq_update_depths(struct bfq_data *bfqd,
* limit 'something'.
*/
/* no more than 50% of tags for async I/O */
- bfqd->word_depths[0][0] = max(bt->sb.depth >> 1, 1U);
+ bfqd->word_depths[0][0] = max((1U << bt->sb.shift) >> 1, 1U);
/*
* no more than 75% of tags for sync writes (25% extra tags
* w.r.t. async I/O, to prevent async I/O from starving sync
* writes)
*/
- bfqd->word_depths[0][1] = max((bt->sb.depth * 3) >> 2, 1U);
+ bfqd->word_depths[0][1] = max(((1U << bt->sb.shift) * 3) >> 2, 1U);
/*
* In-word depths in case some bfq_queue is being weight-
@@ -5296,9 +5296,9 @@ static unsigned int bfq_update_depths(struct bfq_data *bfqd,
* shortage.
*/
/* no more than ~18% of tags for async I/O */
- bfqd->word_depths[1][0] = max((bt->sb.depth * 3) >> 4, 1U);
+ bfqd->word_depths[1][0] = max(((1U << bt->sb.shift) * 3) >> 4, 1U);
/* no more than ~37% of tags for sync writes (~20% extra tags) */
- bfqd->word_depths[1][1] = max((bt->sb.depth * 6) >> 4, 1U);
+ bfqd->word_depths[1][1] = max(((1U << bt->sb.shift) * 6) >> 4, 1U);
for (i = 0; i < 2; i++)
for (j = 0; j < 2; j++)
--
2.27.0
next prev parent reply other threads:[~2021-02-08 19:47 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-08 17:59 [PATCH AUTOSEL 4.19 01/14] arm64: dts: rockchip: Fix PCIe DT properties on rk3399 Sasha Levin
2021-02-08 17:59 ` [PATCH AUTOSEL 4.19 02/14] Input: xpad - sync supported devices with fork on GitHub Sasha Levin
2021-02-08 17:59 ` [PATCH AUTOSEL 4.19 03/14] platform/x86: hp-wmi: Disable tablet-mode reporting by default Sasha Levin
2021-02-08 17:59 ` [PATCH AUTOSEL 4.19 04/14] ovl: perform vfs_getxattr() with mounter creds Sasha Levin
2021-02-08 17:59 ` [PATCH AUTOSEL 4.19 05/14] cap: fix conversions on getxattr Sasha Levin
2021-02-08 17:59 ` [PATCH AUTOSEL 4.19 06/14] ovl: skip getxattr of security labels Sasha Levin
2021-02-08 17:59 ` [PATCH AUTOSEL 4.19 07/14] drm/amd/display: Fix dc_sink kref count in emulated_link_detect Sasha Levin
2021-02-08 17:59 ` [PATCH AUTOSEL 4.19 08/14] drm/amd/display: Free atomic state after drm_atomic_commit Sasha Levin
2021-02-08 17:59 ` [PATCH AUTOSEL 4.19 09/14] riscv: virt_addr_valid must check the address belongs to linear mapping Sasha Levin
2021-02-08 17:59 ` Sasha Levin [this message]
2021-02-08 17:59 ` [PATCH AUTOSEL 4.19 11/14] ARM: dts: lpc32xx: Revert set default clock rate of HCLK PLL Sasha Levin
2021-02-08 17:59 ` [PATCH AUTOSEL 4.19 12/14] ARM: ensure the signal page contains defined contents Sasha Levin
2021-02-08 17:59 ` [PATCH AUTOSEL 4.19 13/14] ARM: kexec: fix oops after TLB are invalidated Sasha Levin
2021-02-08 17:59 ` [PATCH AUTOSEL 4.19 14/14] init/gcov: allow CONFIG_CONSTRUCTORS on UML to fix module gcov Sasha Levin
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