On Tue, 12 Jun 2018 11:32:23 -0400 Christian Hansen <chans...@cisco.com> wrote:
> Adding a flag which will use the kernels's idle
> page tracking to mark pages idle. As the tool already
> prints the idle flag if set, subsequent runs will show
> which pages have been accessed since last run.
That sounds useful.
This patch seems to have been prepared against the mainline kernel, so
it conflicts with your "tools: modifying page-types to include shared
map counts" patch. Awkward, but I seem to have got it fixed up.
> ...
>
> @@ -566,6 +570,30 @@ static int unpoison_page(unsigned long offset)
> return 0;
> }
>
> +static int mark_page_idle(unsigned long offset)
> +{
> + static unsigned long off;
> + static uint64_t buf;
> + int len;
> +
> + if ((offset / 64 == off / 64) || buf == 0) {
> + buf |= 1UL << (offset % 64);
> + off = offset;
> + return 0;
> + }
> +
> + len = pwrite(page_idle_fd, &buf, 8, 8 * (off / 64));
> + if (len < 0) {
> + perror("mark page idle");
> + return len;
> + }
> +
> + buf = 1UL << (offset % 64);
> + off = offset;
> +
> + return 0;
> +}
This is a bit cumbersome. Why not this way:
static int mark_page_idle(unsigned long offset)
{
static unsigned long off;
static uint64_t buf;
int len;
if ((offset / 64 != off / 64) && buf != 0) {
len = pwrite(page_idle_fd, &buf, 8, 8 * (off / 64));
if (len < 0) {
perror("mark page idle");
return len;
}
}
buf = 1UL << (offset % 64);
off = offset;
return 0;
}
Also, it's not very clear what's going on here - the handling of
offset, off and buf. Some well-crafted comments would help.
>
> ...
>
