From: Paul Gortmaker <paul.gortmaker@windriver.com>
To: linux-kernel@vger.kernel.org
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>,
Yury Norov <yury.norov@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
"Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH 1/3] lib: add "all" and "none" as valid ranges to bitmap_parselist()
Date: Thu, 21 Jan 2021 17:33:53 -0500 [thread overview]
Message-ID: <20210121223355.59780-2-paul.gortmaker@windriver.com> (raw)
In-Reply-To: <20210121223355.59780-1-paul.gortmaker@windriver.com>
The use of "all" was originally RCU specific - I'd pushed it down to
being used for any CPU lists -- then Yuri suggested pushing it down
further to be used by any bitmap, which is done here.
As a trivial one line extension, we also accept the inverse "none"
as a valid alias.
Cc: Yury Norov <yury.norov@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
Documentation/admin-guide/kernel-parameters.rst | 11 +++++++++++
lib/bitmap.c | 9 +++++++++
2 files changed, 20 insertions(+)
diff --git a/Documentation/admin-guide/kernel-parameters.rst b/Documentation/admin-guide/kernel-parameters.rst
index 682ab28b5c94..5e080080b058 100644
--- a/Documentation/admin-guide/kernel-parameters.rst
+++ b/Documentation/admin-guide/kernel-parameters.rst
@@ -68,7 +68,18 @@ For example one can add to the command line following parameter:
where the final item represents CPUs 100,101,125,126,150,151,...
+The following convenience aliases are also accepted and used:
+ foo_cpus=all
+
+will provide an full/all-set cpu mask for the associated boot argument.
+
+ foo_cpus=none
+
+will provide an empty/cleared cpu mask for the associated boot argument.
+
+Note that "all" and "none" are not necessarily valid/sensible input values
+for each available boot parameter expecting a CPU list.
This document may not be entirely up to date and comprehensive. The command
"modinfo -p ${modulename}" shows a current list of all parameters of a loadable
diff --git a/lib/bitmap.c b/lib/bitmap.c
index 75006c4036e9..a1010646fbe5 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -627,6 +627,7 @@ static const char *bitmap_parse_region(const char *str, struct region *r)
* From each group will be used only defined amount of bits.
* Syntax: range:used_size/group_size
* Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769
+ * Optionally the self-descriptive "all" or "none" can be used.
*
* Returns: 0 on success, -errno on invalid input strings. Error values:
*
@@ -640,8 +641,16 @@ int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits)
struct region r;
long ret;
+ if (!strcmp(buf, "all")) {
+ bitmap_fill(maskp, nmaskbits);
+ return 0;
+ }
+
bitmap_zero(maskp, nmaskbits);
+ if (!strcmp(buf, "none"))
+ return 0;
+
while (buf) {
buf = bitmap_find_region(buf);
if (buf == NULL)
--
2.17.1
next prev parent reply other threads:[~2021-01-21 22:35 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-21 22:33 [PATCH v2 0/3] :support for bitmap (and hence CPU) list abbreviations Paul Gortmaker
2021-01-21 22:33 ` Paul Gortmaker [this message]
2021-01-22 0:07 ` [PATCH 1/3] lib: add "all" and "none" as valid ranges to bitmap_parselist() Yury Norov
2021-01-22 4:34 ` Paul Gortmaker
2021-01-21 22:33 ` [PATCH 2/3] rcu: dont special case "all" handling; let bitmask deal with it Paul Gortmaker
2021-01-21 22:33 ` [PATCH 3/3] lib: support N as end of range in bitmap_parselist() Paul Gortmaker
2021-01-22 0:29 ` Yury Norov
2021-01-22 4:43 ` Paul Gortmaker
2021-01-22 23:08 ` Yury Norov
2021-01-26 17:18 ` Paul Gortmaker
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