From: Sebastien GODARD <sysstat@users.noreply.github.com>
Date: Sun, 4 Mar 2018 09:53:55 +0000 (+0100)
Subject: sar: Better assess size of buffers that need to be reallocated
X-Git-Tag: v11.7.3~22
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=16359471b3926bc2eb5375162b610069afc1f31d;p=sysstat

sar: Better assess size of buffers that need to be reallocated

When a buffer needs to be reallocated, doubling its size may not be
enough to contain all the additional items.
Assess the needed size based on a value giving the minimum number of
items the buffer should be able to contain.

Signed-off-by: Sebastien GODARD <sysstat@users.noreply.github.com>
---

diff --git a/pr_stats.c b/pr_stats.c
index 90073b2..9ba63a5 100644
--- a/pr_stats.c
+++ b/pr_stats.c
@@ -2673,7 +2673,7 @@ void stub_print_pwr_usb_stats(struct activity *a, int curr, int dispavg)
 				 * No free slot has been found for current device.
 				 * So enlarge buffers then save device in list.
 				 */
-				reallocate_all_buffers(a);
+				reallocate_all_buffers(a, j);
 				sum = (struct stats_pwr_usb *) ((char *) a->buf[2] + j * a->msize);
 				*sum = *suc;
 				a->nr[2] = j + 1;
@@ -2821,7 +2821,7 @@ __print_funct_t stub_print_filesystem_stats(struct activity *a, int prev, int cu
 				 * No free slot has been found for current filesystem.
 				 * So enlarge buffers then save filesystem in list.
 				 */
-				reallocate_all_buffers(a);
+				reallocate_all_buffers(a, j);
 				sfm = (struct stats_filesystem *) ((char *) a->buf[2] + j * a->msize);
 				*sfm = *sfc;
 				a->nr[2] = j + 1;
diff --git a/sa.h b/sa.h
index 871c578..0d75b60 100644
--- a/sa.h
+++ b/sa.h
@@ -1289,7 +1289,7 @@ __nr_t read_nr_value
 int read_record_hdr
 	(int, void *, struct record_header *, struct file_header *, int, int);
 void reallocate_all_buffers
-	(struct activity *);
+	(struct activity *, __nr_t);
 void remap_struct
 	(unsigned int [], unsigned int [], void *, unsigned int);
 void replace_nonprintable_char
diff --git a/sa_common.c b/sa_common.c
index a5579a8..75c90ba 100644
--- a/sa_common.c
+++ b/sa_common.c
@@ -435,23 +435,31 @@ void free_structures(struct activity *act[])
 
 /*
  ***************************************************************************
- * Reallocate all the buffers for given activity. The new size is the double
- * of the original one.
+ * Reallocate all the buffers for a given activity.
  *
  * IN:
- * @a	Activity whose buffers need to be reallocated.
+ * @a		Activity whose buffers need to be reallocated.
+ * @nr_min	Minimum number of items that the new buffers should be able
+ *		to receive.
  ***************************************************************************
  */
-void reallocate_all_buffers(struct activity *a)
+void reallocate_all_buffers(struct activity *a, __nr_t nr_min)
 {
 	int j;
 	size_t nr_realloc;
 
+	if (nr_min <= 0) {
+		nr_min = 1;
+	}
 	if (!a->nr_allocated) {
-		nr_realloc = (a->nr_ini ? a->nr_ini : 1);
+		nr_realloc = nr_min;
 	}
 	else {
-		nr_realloc = a->nr_allocated * 2;
+		nr_realloc = a->nr_allocated;
+		do {
+			nr_realloc = nr_realloc * 2;
+		}
+		while (nr_realloc < nr_min);
 	}
 
 	for (j = 0; j < 3; j++) {
@@ -460,7 +468,7 @@ void reallocate_all_buffers(struct activity *a)
 		/* Init additional space which has been allocated */
 		if (a->nr_allocated) {
 			memset(a->buf[j] + a->msize * a->nr_allocated * a->nr2, 0,
-			       (size_t) a->msize * (size_t) a->nr_allocated * (size_t) a->nr2);
+			       (size_t) a->msize * (size_t) (nr_realloc - a->nr_allocated) * (size_t) a->nr2);
 		}
 	}
 
@@ -1514,7 +1522,7 @@ void read_file_stat_bunch(struct activity *act[], int curr, int ifd, int act_nr,
 
 		/* Reallocate buffers if needed */
 		if (nr_value > act[p]->nr_allocated) {
-			reallocate_all_buffers(act[p]);
+			reallocate_all_buffers(act[p], nr_value);
 		}
 
 		/*
@@ -2649,7 +2657,7 @@ int print_special_record(struct record_header *record_hdr, unsigned int l_flags,
 		p = get_activity_position(act, A_CPU, EXIT_IF_NOT_FOUND);
 		act[p]->nr_ini = file_hdr->sa_cpu_nr;
 		if (act[p]->nr_ini > act[p]->nr_allocated) {
-			reallocate_all_buffers(act[p]);
+			reallocate_all_buffers(act[p], act[p]->nr_ini);
 		}
 
 		if (!dp)
diff --git a/sar.c b/sar.c
index 8ba575a..c0c85ab 100644
--- a/sar.c
+++ b/sar.c
@@ -685,7 +685,7 @@ void read_sadc_stat_bunch(int curr)
 				print_read_error(INCONSISTENT_INPUT_DATA);
 			}
 			if (act[p]->nr[curr] > act[p]->nr_allocated) {
-				reallocate_all_buffers(act[p]);
+				reallocate_all_buffers(act[p], act[p]->nr[curr]);
 			}