resource: process: Handle the case that target cannot support taskstats

Since PROCESS resource has some attributes which require taskstats,
those attributes are mark to unsupported or provided by other methods
when the target does not support taskstats.

Change-Id: I83a0eab243367f59c518d1b1c422b741f3e611bb
Signed-off-by: Dongwoo Lee <dwoo08.lee@samsung.com>

diff --git a/src/resource/resource-process.c b/src/resource/resource-process.c
index 633fc78..192d91e 100644 (file)
--- a/src/resource/resource-process.c
+++ b/src/resource/resource-process.c
@@ -41,6 +41,7 @@ struct process_context {
 };
 
 static long jiffy;
+static int taskstat_support = -1;
 
 static int process_get_cpu_util(struct resource *res,
                                const struct resource_attribute *attr,
@@ -194,6 +195,21 @@ static int process_get_context_data(struct resource *res,
 
        switch (attr->id) {
        case PROCESS_ATTR_NAME:
+               if (!taskstat_support && (strlen(ctx->comm) == 0)) {
+                       char *stat_fields[PROCESS_STAT_FIELD_MAX];
+                       char buffer[BUFF_MAX];
+                       int ret, len;
+
+                       ret = kernel_get_process_stat_fields(ctx->tgid, buffer,
+                                                            BUFF_MAX, stat_fields);
+                       if (ret < 0)
+                               break;
+
+                       len = strlen(stat_fields[PROCESS_STAT_FIELD_COMM]) - 2/* '(', ')' */;
+                       len = (len < TS_COMM_LEN - 1) ? len : TS_COMM_LEN - 1;
+                       strncpy(ctx->comm, stat_fields[PROCESS_STAT_FIELD_COMM] + 1, len);
+               }
+
                strncpy((char *)data, ctx->comm, TS_COMM_LEN);
                break;
        case PROCESS_ATTR_PGID:
@@ -213,6 +229,19 @@ static int process_get_context_data(struct resource *res,
                *((int *)data) = ctx->pgid;
                break;
        case PROCESS_ATTR_PPID:
+               if (ctx->ppid < 0) {
+                       char *stat_fields[PROCESS_STAT_FIELD_MAX];
+                       char buffer[BUFF_MAX];
+                       int ret;
+
+                       ret = kernel_get_process_stat_fields(ctx->tgid, buffer,
+                                                            BUFF_MAX, stat_fields);
+                       if (ret < 0)
+                               break;
+
+                       ctx->ppid = atoi(stat_fields[PROCESS_STAT_FIELD_PPID]);
+               }
+
                *((int *)data) = ctx->ppid;
                break;
        }
@@ -220,6 +249,12 @@ static int process_get_context_data(struct resource *res,
        return 0;
 }
 
+static bool process_check_taskstat_support(struct resource *resource,
+                                           const struct resource_attribute *attr)
+{
+       return !!taskstat_support;
+}
+
 static bool process_check_gpu_support(struct resource *resource,
                                            const struct resource_attribute *attr)
 {
@@ -233,7 +268,7 @@ static const struct resource_attribute process_attrs[] = {
                .type   = DATA_TYPE_DOUBLE,
                .ops    = {
                        .get = process_get_cpu_util,
-                       .is_supported = resource_attr_supported_always,
+                       .is_supported = process_check_taskstat_support,
                },
        }, {
                .name   = "PROCESS_ATTR_MEM_VIRT",
@@ -241,7 +276,7 @@ static const struct resource_attribute process_attrs[] = {
                .type   = DATA_TYPE_UINT64,
                .ops    = {
                        .get = process_get_mem_attrs,
-                       .is_supported = resource_attr_supported_always,
+                       .is_supported = process_check_taskstat_support,
                },
        }, {
                .name   = "PROCESS_ATTR_MEM_RSS",
@@ -249,7 +284,7 @@ static const struct resource_attribute process_attrs[] = {
                .type   = DATA_TYPE_UINT64,
                .ops    = {
                        .get = process_get_mem_attrs,
-                       .is_supported = resource_attr_supported_always,
+                       .is_supported = process_check_taskstat_support,
                },
        }, {
                .name   = "PROCESS_ATTR_MEM_RSS_PERCENT",
@@ -257,7 +292,7 @@ static const struct resource_attribute process_attrs[] = {
                .type   = DATA_TYPE_DOUBLE,
                .ops    = {
                        .get = process_get_mem_attrs,
-                       .is_supported = resource_attr_supported_always,
+                       .is_supported = process_check_taskstat_support,
                },
        }, {
                .name   = "PROCESS_ATTR_DISK_READ_PER_SEC",
@@ -265,7 +300,7 @@ static const struct resource_attribute process_attrs[] = {
                .type   = DATA_TYPE_DOUBLE,
                .ops    = {
                        .get = process_get_disk_attrs,
-                       .is_supported = resource_attr_supported_always,
+                       .is_supported = process_check_taskstat_support,
                },
        }, {
                .name   = "PROCESS_ATTR_DISK_WRITE_PER_SEC",
@@ -273,7 +308,7 @@ static const struct resource_attribute process_attrs[] = {
                .type   = DATA_TYPE_DOUBLE,
                .ops    = {
                        .get = process_get_disk_attrs,
-                       .is_supported = resource_attr_supported_always,
+                       .is_supported = process_check_taskstat_support,
                },
        }, {
                .name   = "PROCESS_ATTR_NAME",
@@ -379,19 +414,29 @@ static int process_setup_tgid(struct resource *res,
        ctx->prev_total_time = get_total_cpu_time();
 
        /* update initial status */
-       ret = kernel_get_thread_group_taskstats(&ctx->curr, ctx->tgid, true);
-       if (ret < 0)
-               return ret;
+       if (taskstat_support) {
+               ret = kernel_get_thread_group_taskstats(&ctx->curr, ctx->tgid, true);
+               if (ret < 0)
+                       return ret;
+
+               memcpy(ctx->comm, ctx->curr.ac_comm, strlen(ctx->curr.ac_comm) + 1);
+               ctx->ppid = ctx->curr.ac_ppid;
+       } else {
+               /*
+                * if taskstat is not supported, comm, pgid and ppid is retrieved
+                * from procfs status lazily.
+                *
+                * ctx->comm is now "\0" so it is treated as not initialized.
+                */
+               ctx->ppid = -1;
+       }
+
+       ctx->pgid = -1;
 
        ret = kernel_get_thread_group_map_info(&ctx->map_info, ctx->tgid, include_gpu_mem);
        if (ret < 0)
                return ret;
 
-       memcpy(ctx->comm, ctx->curr.ac_comm, strlen(ctx->curr.ac_comm) + 1);
-
-       ctx->pgid = -1;
-       ctx->ppid = ctx->curr.ac_ppid;
-
        return 0;
 }
 
@@ -421,11 +466,12 @@ static int process_prepare_update(struct resource *res)
 
        include_gpu_mem = is_resource_attr_interested(res, PROCESS_GROUP_ATTR_MEM_GPU);
 
-       memcpy(&ctx->prev, &ctx->curr, sizeof(struct taskstats));
-
-       ret = kernel_get_thread_group_taskstats(&ctx->curr, ctx->tgid, false);
-       if (ret < 0)
-               return ret;
+       if (taskstat_support) {
+               memcpy(&ctx->prev, &ctx->curr, sizeof(struct taskstats));
+               ret = kernel_get_thread_group_taskstats(&ctx->curr, ctx->tgid, false);
+               if (ret < 0)
+                       return ret;
+       }
 
        ret = kernel_get_thread_group_map_info(&ctx->map_info, ctx->tgid, include_gpu_mem);
        if (ret < 0)
@@ -453,6 +499,9 @@ static int process_init(struct resource *res)
                        return -EINVAL;
        }
 
+       if (taskstat_support < 0)
+               taskstat_support = (int)kernel_check_taskstat_support();
+
        ctx = calloc(1, sizeof(struct process_context));
        if (!ctx)
                return -ENOMEM;