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library: refactor exposed pointers management, 3rd gen

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This commit brings all of those 'fetch' type functions
(supporting some form of 'reap') into closer alignment
with one another. The biggest impact is to be found in
the <stat> module, which now provides for the separate
copy of stack pointers which will be exposed to users.

The reason such a copy was not employed initially with
<stat>, unlike those for <pids> and <slabinfo>, is due
to the fact that such stacks were never sortable. Thus
the original raw consolidated extent pointers wouldn't
have been disturbed. But that meant no NULL delimiter.

So with this commit, all reap/fetch operations now use
pointer copies when returning results to callers. And,
all such arrays are now NULL delimited meaning callers
can choose their own access fencepost: totals or NULL.

Signed-off-by: Jim Warner <james.warner@comcast.net>
This commit is contained in:
Jim Warner
2016-07-01 00:00:00 -05:00
committed by Craig Small
parent 4fe52ccd44
commit 80ad63dc31
3 changed files with 58 additions and 29 deletions
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54
proc/stat.c
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@ -105,8 +105,9 @@ struct reap_support {
int total; // independently obtained # of cpus/nodes
struct ext_support fetch; // extents plus items details
struct tic_support hist; // cpu and node jiffies management
int n_anchor_alloc; // last known anchor pointers allocation
int n_alloc; // last known anchor pointers allocation
struct stat_stack **anchor; // reapable stacks (consolidated extents)
int n_alloc_save; // last known results.stacks allocation
struct stat_reap result; // summary + stacks returned to caller
};
@ -649,6 +650,9 @@ static int stacks_fetch_tics (
struct procps_statinfo *info,
struct reap_support *this)
{
#define n_alloc this->n_alloc
#define n_inuse this->hist.n_inuse
#define n_saved this->n_alloc_save
struct stacks_extent *ext;
int i;
@ -659,21 +663,21 @@ static int stacks_fetch_tics (
if (!this->anchor) {
if (!(this->anchor = calloc(sizeof(void *), STACKS_INCR)))
return -ENOMEM;
this->n_anchor_alloc = STACKS_INCR;
n_alloc = STACKS_INCR;
}
if (!this->fetch.extents) {
if (!(ext = stacks_alloc(&this->fetch, this->n_anchor_alloc)))
if (!(ext = stacks_alloc(&this->fetch, n_alloc)))
return -ENOMEM;
memcpy(this->anchor, ext->stacks, sizeof(void *) * this->n_anchor_alloc);
memcpy(this->anchor, ext->stacks, sizeof(void *) * n_alloc);
}
if (this->fetch.dirty_stacks)
cleanup_stacks_all(&this->fetch);
// iterate stuff --------------------------------------
for (i = 0; i < this->hist.n_inuse; i++) {
if (!(i < this->n_anchor_alloc)) {
this->n_anchor_alloc += STACKS_INCR;
if ((!(this->anchor = realloc(this->anchor, sizeof(void *) * this->n_anchor_alloc)))
for (i = 0; i < n_inuse; i++) {
if (!(i < n_alloc)) {
n_alloc += STACKS_INCR;
if ((!(this->anchor = realloc(this->anchor, sizeof(void *) * n_alloc)))
|| (!(ext = stacks_alloc(&this->fetch, STACKS_INCR)))) {
return -ENOMEM;
}
@ -683,12 +687,25 @@ static int stacks_fetch_tics (
}
// finalize stuff -------------------------------------
/* note: we go to this trouble of maintaining a duplicate of the consolidated |
extent stacks addresses represented as our 'anchor' since these ptrs |
are exposed to a user (um, not that we don't trust 'em or anything). |
plus, we can NULL delimit these ptrs which we couldn't do otherwise. | */
if (n_saved < i + 1) {
n_saved = i + 1;
if (!(this->result.stacks = realloc(this->result.stacks, sizeof(void *) * n_saved)))
return -ENOMEM;
}
memcpy(this->result.stacks, this->anchor, sizeof(void *) * i);
this->result.stacks[i] = NULL;
this->result.total = i;
this->result.stacks = this->anchor;
this->fetch.dirty_stacks = 1;
// callers beware, this might be zero (maybe no libnuma.so) ...
return this->result.total;
#undef n_alloc
#undef n_inuse
#undef n_saved
} // end: stacks_fetch_tics
@ -766,6 +783,7 @@ PROCPS_EXPORT int procps_stat_new (
p->refcount = 1;
p->stat_fd = -1;
p->results.cpus = &p->cpus.result;
p->results.nodes = &p->nodes.result;
p->cpus.total = procps_cpu_count();
@ -824,6 +842,8 @@ PROCPS_EXPORT int procps_stat_unref (
if ((*info)->refcount == 0) {
if ((*info)->cpus.anchor)
free((*info)->cpus.anchor);
if ((*info)->cpus.result.stacks)
free((*info)->cpus.result.stacks);
if ((*info)->cpus.hist.tics)
free((*info)->cpus.hist.tics);
if ((*info)->cpus.fetch.extents)
@ -831,6 +851,8 @@ PROCPS_EXPORT int procps_stat_unref (
if ((*info)->nodes.anchor)
free((*info)->nodes.anchor);
if ((*info)->nodes.result.stacks)
free((*info)->nodes.result.stacks);
if ((*info)->nodes.hist.tics)
free((*info)->nodes.hist.tics);
if ((*info)->nodes.fetch.extents)
@ -911,11 +933,6 @@ PROCPS_EXPORT struct stat_reaped *procps_stat_reap (
if (info == NULL || items == NULL)
return NULL;
info->results.summary = NULL;
info->cpus.result.total = info->nodes.result.total = 0;
info->cpus.result.stacks = info->nodes.result.stacks = NULL;
if (what != STAT_REAP_CPUS_ONLY && what != STAT_REAP_CPUS_AND_NODES)
return NULL;
@ -940,6 +957,15 @@ PROCPS_EXPORT struct stat_reaped *procps_stat_reap (
return NULL;
info->results.summary = update_single_stack(info, &info->cpu_summary);
/* unlike the other 'reap' functions, <stat> provides for two separate
stacks pointer arrays exposed to callers. Thus, to keep our promise
of NULL delimit we must ensure a minimal array for the optional one */
if (!info->nodes.result.stacks
&& (!(info->nodes.result.stacks = malloc(sizeof(void *)))))
return NULL;
info->nodes.result.total = 0;
info->nodes.result.stacks[0] = NULL;
switch (what) {
case STAT_REAP_CPUS_ONLY:
if (!stacks_fetch_tics(info, &info->cpus))