2021-04-08 13:45:14

by Hui Zhu

Subject: [PATCH for vm-scalability] usemem: Add code for touch-alloc

Add code for touch-alloc.
And Change read memory to write memory to avoid use the zero-page for
reads in do_anonymous_page.

Signed-off-by: Hui Zhu <[email protected]>
---
usemem.c | 34 ++++++++++++++++++++++------------
1 file changed, 22 insertions(+), 12 deletions(-)

diff --git a/usemem.c b/usemem.c
index e2c46ec..5b90aae 100644
--- a/usemem.c
+++ b/usemem.c
@@ -329,6 +329,18 @@ void detach(void)
}
}

+unsigned long do_access(unsigned long *p, unsigned long idx, int read)
+{
+ volatile unsigned long *vp = p;
+
+ if (read)
+ return vp[idx]; /* read data */
+ else {
+ vp[idx] = idx; /* write data */
+ return 0;
+ }
+}
+
unsigned long * allocate(unsigned long bytes)
{
unsigned long *p;
@@ -355,6 +367,14 @@ unsigned long * allocate(unsigned long bytes)
p = (unsigned long *)ALIGN((unsigned long)p, pagesize - 1);
}

+ if (opt_touch_alloc) {
+ unsigned long i;
+ unsigned long m = bytes / sizeof(*p);
+
+ for (i = 0; i < m; i += 1)
+ do_access(p, i, 0);
+ }
+
return p;
}

@@ -436,18 +456,6 @@ void shm_unlock(int seg_id)
shmctl(seg_id, SHM_UNLOCK, NULL);
}

-unsigned long do_access(unsigned long *p, unsigned long idx, int read)
-{
- volatile unsigned long *vp = p;
-
- if (read)
- return vp[idx]; /* read data */
- else {
- vp[idx] = idx; /* write data */
- return 0;
- }
-}
-
#define NSEC_PER_SEC (1UL * 1000 * 1000 * 1000)

long nsec_sub(long nsec1, long nsec2)
@@ -953,6 +961,8 @@ int main(int argc, char *argv[])
opt_punch_holes = 1;
} else if (strcmp(opts[opt_index].name, "init-time") == 0) {
opt_init_time = 1;
+ } else if (strcmp(opts[opt_index].name, "touch-alloc") == 0) {
+ opt_touch_alloc = 1;
} else
usage(1);
break;
--
2.17.1

2021-04-10 01:06:19

by Wu Fengguang

Subject: Re: [PATCH for vm-scalability] usemem: Add code for touch-alloc

Applied, thanks!

On Thu, Apr 08, 2021 at 09:42:55PM +0800, Hui Zhu wrote:
>Add code for touch-alloc.
>And Change read memory to write memory to avoid use the zero-page for
>reads in do_anonymous_page.
>
>Signed-off-by: Hui Zhu <[email protected]>
>---
> usemem.c | 34 ++++++++++++++++++++++------------
> 1 file changed, 22 insertions(+), 12 deletions(-)
>
>diff --git a/usemem.c b/usemem.c
>index e2c46ec..5b90aae 100644
>--- a/usemem.c
>+++ b/usemem.c
>@@ -329,6 +329,18 @@ void detach(void)
> }
> }
>
>+unsigned long do_access(unsigned long *p, unsigned long idx, int read)
>+{
>+ volatile unsigned long *vp = p;
>+
>+ if (read)
>+ return vp[idx]; /* read data */
>+ else {
>+ vp[idx] = idx; /* write data */
>+ return 0;
>+ }
>+}
>+
> unsigned long * allocate(unsigned long bytes)
> {
> unsigned long *p;
>@@ -355,6 +367,14 @@ unsigned long * allocate(unsigned long bytes)
> p = (unsigned long *)ALIGN((unsigned long)p, pagesize - 1);
> }
>
>+ if (opt_touch_alloc) {
>+ unsigned long i;
>+ unsigned long m = bytes / sizeof(*p);
>+
>+ for (i = 0; i < m; i += 1)
>+ do_access(p, i, 0);
>+ }
>+
> return p;
> }
>
>@@ -436,18 +456,6 @@ void shm_unlock(int seg_id)
> shmctl(seg_id, SHM_UNLOCK, NULL);
> }
>
>-unsigned long do_access(unsigned long *p, unsigned long idx, int read)
>-{
>- volatile unsigned long *vp = p;
>-
>- if (read)
>- return vp[idx]; /* read data */
>- else {
>- vp[idx] = idx; /* write data */
>- return 0;
>- }
>-}
>-
> #define NSEC_PER_SEC (1UL * 1000 * 1000 * 1000)
>
> long nsec_sub(long nsec1, long nsec2)
>@@ -953,6 +961,8 @@ int main(int argc, char *argv[])
> opt_punch_holes = 1;
> } else if (strcmp(opts[opt_index].name, "init-time") == 0) {
> opt_init_time = 1;
>+ } else if (strcmp(opts[opt_index].name, "touch-alloc") == 0) {
>+ opt_touch_alloc = 1;
> } else
> usage(1);
> break;
>--
>2.17.1
>