From: Wei Yang <richard.weiyang@gmail.com>
To: willy@infradead.org
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
Wei Yang <richard.weiyang@gmail.com>
Subject: [PATCH 2/9] XArray: simplify the calculation of shift
Date: Mon, 30 Mar 2020 12:36:36 +0000 [thread overview]
Message-ID: <20200330123643.17120-3-richard.weiyang@gmail.com> (raw)
In-Reply-To: <20200330123643.17120-1-richard.weiyang@gmail.com>
When head is NULL, shift is calculated from max. Currently we use a loop
to detect how many XA_CHUNK_SHIFT is need to cover max.
To achieve this, we can get number of bits max expands and round it up
to XA_CHUNK_SHIFT.
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
---
lib/xarray.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)
diff --git a/lib/xarray.c b/lib/xarray.c
index 1d9fab7db8da..6454cf3f5b4c 100644
--- a/lib/xarray.c
+++ b/lib/xarray.c
@@ -560,11 +560,7 @@ static int xas_expand(struct xa_state *xas, void *head)
unsigned long max = xas_max(xas);
if (!head) {
- if (max == 0)
- return 0;
- while ((max >> shift) >= XA_CHUNK_SIZE)
- shift += XA_CHUNK_SHIFT;
- return shift + XA_CHUNK_SHIFT;
+ return roundup(fls_long(max), XA_CHUNK_SHIFT);
} else if (xa_is_node(head)) {
node = xa_to_node(head);
shift = node->shift + XA_CHUNK_SHIFT;
--
2.23.0
next prev parent reply other threads:[~2020-03-30 12:37 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-30 12:36 [PATCH 0/9] XArray: several cleanups Wei Yang
2020-03-30 12:36 ` [PATCH 1/9] XArray: fix comment on Zero/Retry entry Wei Yang
2020-03-30 12:46 ` Matthew Wilcox
2020-03-30 13:42 ` Wei Yang
2020-03-30 12:36 ` Wei Yang [this message]
2020-03-30 13:20 ` [PATCH 2/9] XArray: simplify the calculation of shift Matthew Wilcox
2020-03-30 14:07 ` Wei Yang
2020-03-30 12:36 ` [PATCH 3/9] XArray: handle a NULL head by itself Wei Yang
2020-03-30 12:36 ` [PATCH 4/9] XArray: don't expect to have more nr_values than count Wei Yang
2020-03-30 12:36 ` [PATCH 5/9] XArray: entry in last level is not expected to be a node Wei Yang
2020-03-30 12:48 ` Matthew Wilcox
2020-03-30 14:15 ` Wei Yang
2020-03-30 14:28 ` Matthew Wilcox
2020-03-30 22:10 ` Wei Yang
2020-03-31 13:42 ` Wei Yang
2020-03-31 16:42 ` Matthew Wilcox
2020-03-31 22:04 ` Wei Yang
2020-03-31 23:59 ` Matthew Wilcox
2020-04-01 22:10 ` Wei Yang
2020-04-01 22:20 ` Matthew Wilcox
2020-04-02 12:36 ` Wei Yang
2020-04-03 22:39 ` Wei Yang
2020-04-04 15:37 ` Matthew Wilcox
2020-04-05 11:07 ` Wei Yang
2020-04-05 21:56 ` Matthew Wilcox
2020-04-06 1:14 ` Wei Yang
2020-04-06 1:24 ` Wei Yang
2020-04-11 13:56 ` Wei Yang
2020-04-28 21:24 ` Wei Yang
2020-03-30 12:36 ` [PATCH 6/9] XArray: internal node is a xa_node when it is bigger than XA_ZERO_ENTRY Wei Yang
2020-03-30 12:50 ` Matthew Wilcox
2020-03-30 13:45 ` Wei Yang
2020-03-30 13:49 ` Matthew Wilcox
2020-03-30 14:13 ` Wei Yang
2020-03-30 14:27 ` Matthew Wilcox
2020-03-30 22:20 ` Wei Yang
2020-03-31 0:06 ` Matthew Wilcox
2020-03-31 13:40 ` Wei Yang
2020-03-30 12:36 ` [PATCH 7/9] XArray: the NULL xa_node condition is handled in xas_top Wei Yang
2020-03-30 12:36 ` [PATCH 8/9] XArray: take xas_error() handling for clearer logic Wei Yang
2020-03-30 12:36 ` [PATCH 9/9] XArray: adjust xa_offset till it gets the correct node Wei Yang
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