On Thu, 23 Mar 2017 19:16:43 +0100
Andrea Bolognani <abologna@xxxxxxxxxx> wrote:
> The value we use internally to represent the lack of a memory
> locking limit, VIR_DOMAIN_MEMORY_PARAM_UNLIMITED, doesn't
> match the value setrlimit() and prlimit() use for the same
> purpose, RLIM_INFINITY, so we have to handle the translation
> ourselves.
> ---
> src/util/virprocess.c | 20 +++++++++++++++++---
> 1 file changed, 17 insertions(+), 3 deletions(-)
>
> diff --git a/src/util/virprocess.c b/src/util/virprocess.c
> index 16eb412..1fbbbb3 100644
> --- a/src/util/virprocess.c
> +++ b/src/util/virprocess.c
> @@ -747,7 +747,15 @@ virProcessSetMaxMemLock(pid_t pid, unsigned long long bytes)
> if (bytes == 0)
> return 0;
>
> - rlim.rlim_cur = rlim.rlim_max = bytes;
> + /* We use VIR_DOMAIN_MEMORY_PARAM_UNLIMITED internally to represent
> + * unlimited memory amounts, but setrlimit() and prlimit() use
> + * RLIM_INFINITY for the same purpose, so we need to translate between
> + * the two conventions */
> + if (virMemoryLimitIsSet(bytes))
> + rlim.rlim_cur = rlim.rlim_max = bytes;
> + else
> + rlim.rlim_cur = rlim.rlim_max = RLIM_INFINITY;
I know I'm not very smart, but I had trouble parsing this. What
about:
if (virMemoryLimitIsInfinity(bytes))
rlim.rlim_cur = rlim.rlim_max = RLIM_INFINITY;
...
This reads better, and avoids using virMemoryLimitIsSet() which
seems very error-prone. It doesn't check for zero and it's strange
that "limit < infinity" means "limit is set".
> +
> if (pid == 0) {
> if (setrlimit(RLIMIT_MEMLOCK, &rlim) < 0) {
> virReportSystemError(errno,
> @@ -810,8 +818,14 @@ virProcessGetMaxMemLock(pid_t pid,
> }
>
> /* virProcessSetMaxMemLock() sets both rlim_cur and rlim_max to the
> - * same value, so we can retrieve just rlim_max here */
> - *bytes = rlim.rlim_max;
> + * same value, so we can retrieve just rlim_max here. We use
> + * VIR_DOMAIN_MEMORY_PARAM_UNLIMITED internally to represent unlimited
> + * memory amounts, but setrlimit() and prlimit() use RLIM_INFINITY for the
> + * same purpose, so we need to translate between the two conventions */
> + if (rlim.rlim_max == RLIM_INFINITY)
> + *bytes = VIR_DOMAIN_MEMORY_PARAM_UNLIMITED;
> + else
> + *bytes = rlim.rlim_max;
>
> return 0;
> }
--
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