damon_rand() is called in three files:damon/core.c, damon/
paddr.c, damon/vaddr.c, i think there is no need to redefine
this twice, So move it to damon.h will be a good choice.
Signed-off-by: Xin Hao <[email protected]>
Reviewed-by: SeongJae Park <[email protected]>
---
include/linux/damon.h | 4 ++++
mm/damon/core.c | 4 ----
mm/damon/prmtv-common.h | 4 ----
3 files changed, 4 insertions(+), 8 deletions(-)
diff --git a/include/linux/damon.h b/include/linux/damon.h
index 00ad96f2ec10..c6df025d8704 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -11,12 +11,16 @@
#include <linux/mutex.h>
#include <linux/time64.h>
#include <linux/types.h>
+#include <linux/random.h>
/* Minimal region size. Every damon_region is aligned by this. */
#define DAMON_MIN_REGION PAGE_SIZE
/* Max priority score for DAMON-based operation schemes */
#define DAMOS_MAX_SCORE (99)
+/* Get a random number in [l, r) */
+#define damon_rand(l, r) (l + prandom_u32_max(r - l))
+
/**
* struct damon_addr_range - Represents an address region of [@start, @end).
* @start: Start address of the region (inclusive).
diff --git a/mm/damon/core.c b/mm/damon/core.c
index 4d2c3a0c7c8a..bdec32ef78c0 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -11,7 +11,6 @@
#include <linux/delay.h>
#include <linux/kthread.h>
#include <linux/mm.h>
-#include <linux/random.h>
#include <linux/slab.h>
#include <linux/string.h>
@@ -23,9 +22,6 @@
#define DAMON_MIN_REGION 1
#endif
-/* Get a random number in [l, r) */
-#define damon_rand(l, r) (l + prandom_u32_max(r - l))
-
static DEFINE_MUTEX(damon_lock);
static int nr_running_ctxs;
diff --git a/mm/damon/prmtv-common.h b/mm/damon/prmtv-common.h
index 61f27037603e..e790cb5f8fe0 100644
--- a/mm/damon/prmtv-common.h
+++ b/mm/damon/prmtv-common.h
@@ -6,10 +6,6 @@
*/
#include <linux/damon.h>
-#include <linux/random.h>
-
-/* Get a random number in [l, r) */
-#define damon_rand(l, r) (l + prandom_u32_max(r - l))
struct page *damon_get_page(unsigned long pfn);
--
2.31.0
On Thu, 2 Dec 2021 15:58:59 +0800 Xin Hao <[email protected]> wrote:
> damon_rand() is called in three files:damon/core.c, damon/
> paddr.c, damon/vaddr.c, i think there is no need to redefine
> this twice, So move it to damon.h will be a good choice.
Fair enough.
> +/* Get a random number in [l, r) */
> +#define damon_rand(l, r) (l + prandom_u32_max(r - l))
This shouldn't be implemented as a macro, for all the usual reasons
(typechecking, side-effects, ugliness, code-documentation site, etc).
In particular, this expression references `l' twice, so calling
damon_rand(a++, b);
will increment `a' twice, surprise surprise.
Can someone please send a followup patch to convert this (and any
similar damon macros) into (probably static inlined) C functions?
On Thu, 2 Dec 2021 15:12:13 -0800 Andrew Morton <[email protected]> wrote:
> On Thu, 2 Dec 2021 15:58:59 +0800 Xin Hao <[email protected]> wrote:
>
> > damon_rand() is called in three files:damon/core.c, damon/
> > paddr.c, damon/vaddr.c, i think there is no need to redefine
> > this twice, So move it to damon.h will be a good choice.
>
> Fair enough.
>
> > +/* Get a random number in [l, r) */
> > +#define damon_rand(l, r) (l + prandom_u32_max(r - l))
>
> This shouldn't be implemented as a macro, for all the usual reasons
> (typechecking, side-effects, ugliness, code-documentation site, etc).
Yes, agreed.
>
> In particular, this expression references `l' twice, so calling
>
> damon_rand(a++, b);
>
> will increment `a' twice, surprise surprise.
Thank you for this nice explanation.
>
> Can someone please send a followup patch to convert this (and any
> similar damon macros) into (probably static inlined) C functions?
Sure, I will do, unless someone shows interest here.
Thanks,
SJ
Hi park:
Are you fixing this potential bug? If not, I am willing to modify,
i will send a fixed patch ？
--
Best Regards!
Xin Hao
Hi Xin,
On Mon, 6 Dec 2021 13:20:02 +0800 Xin Hao <[email protected]> wrote:
> Hi park:
>
> Are you fixing this potential bug? If not, I am willing to modify,
> i will send a fixed patch ？
I couldn't find a time slot for this yet. It would be great if you could send
a patch.
Thanks,
SJ
>
> --
> Best Regards!
> Xin Hao
>
On 12/6/21 2:28 PM, SeongJae Park wrote:
> Hi Xin,
>
> On Mon, 6 Dec 2021 13:20:02 +0800 Xin Hao <[email protected]> wrote:
>
>> Hi park:
>>
>> Are you fixing this potential bug? If not, I am willing to modify,
>> i will send a fixed patch ？
> I couldn't find a time slot for this yet. It would be great if you could send
> a patch.
Ok, i will do, thanks!
>
>
> Thanks,
> SJ
>
>> --
>> Best Regards!
>> Xin Hao
>>
--
Best Regards!
Xin Hao