Attachment 153906 Details for Bug 226997 – Patch modifies how /proc/stat is processed.

[patch] Patch modifies how /proc/stat is processed.

patch (text/plain), 2.29 KB, created by George Beshers on 2007-05-01 23:49:52 UTC

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Creator: George Beshers

Created: 2007-05-01 23:49:52 UTC

Size: 2.29 KB

patch

obsolete

>diff -Naur udev-110.Orig/udevd.c udev-110.new/udevd.c
>--- udev-110.Orig/udevd.c	2007-05-01 08:33:39.000000000 -0400
>+++ udev-110.new/udevd.c	2007-05-01 12:49:38.000000000 -0400
>@@ -347,31 +347,21 @@
> 
> static int cpu_count(void)
> {
>-	int f;
>-	char buf[65536];
>+	FILE* f;
>+	char buf[1024];
> 	int len;
> 	const char *pos;
> 	int count = 0;
> 
>-	f = open("/proc/stat", O_RDONLY);
>-	if (f == -1)
>+	f = fopen("/proc/stat", "r");
>+	if (f == NULL)
> 		return -1;
> 
>-	len = read(f, buf, sizeof(buf)-1);
>-	close(f);
>-	if (len <= 0)
>-		return -1;
>-	buf[len] = '\0';
>-
>-	pos = strstr(buf, "cpu");
>-	if (pos == NULL)
>-		return -1;
>-
>-	while (pos != NULL) {
>-		if (strncmp(pos, "cpu", 3) == 0 &&isdigit(pos[3]))
>+	while (fgets(buf, 1024, f) != NULL) {
>+		if (strncmp(buf, "cpu", 3) == 0 && isdigit(buf[3]))
> 			count++;
>-		pos = strstr(&pos[3], "cpu");
> 	}
>+	fclose(f);
> 
> 	if (count == 0)
> 		return -1;
>@@ -380,30 +370,46 @@
> 
> static int running_processes(void)
> {
>-	int f;
>-	char buf[32768];
>+	FILE* f;
>+	char buf[1024];
> 	int len;
>-	int running;
>+	int running = -1;
> 	const char *pos;
>+	int retries = 3;
> 
>-	f = open("/proc/stat", O_RDONLY);
>-	if (f == -1)
>-		return -1;
>-
>-	len = read(f, buf, sizeof(buf)-1);
>-	close(f);
>-	if (len <= 0)
>-		return -1;
>-	buf[len] = '\0';
>-
>-	pos = strstr(buf, "procs_running ");
>-	if (pos == NULL)
>-		return -1;
>+	/*
>+	 * The retries is probably overkill but the text display is
>+	 * changing rapidly.on large systems (>= 512p) and so, while
>+	 * I have not actually recorded an instance where the retry
>+         * was used I would rather not have it fail.
>+	 * 
>+	 * An alternative approach would be to note when we are on
>+	 * a fairly large system (8cpus and 16Gbytes say) at which
>+	 * point throttling is probably not really necessary.
>+	 */
>+	do {
>+		f = fopen("/proc/stat", "r");
>+		if (f == NULL)
>+			return -1;
>+
>+		while (fgets(buf, 1024, f) != NULL) {
>+			pos = strstr(buf, "procs_running ");
>+			if (pos != NULL) {
>+				int res;
>+				res = sscanf(pos, "procs_running %u",
>+					     &running);
>+				if (res == 1) {
>+					fclose(f);
>+					return running;
>+				}
>+				break;
>+			}
>+		}
> 
>-	if (sscanf(pos, "procs_running %u", &running) != 1)
>-		return -1;
>+		fclose(f);
>+	} while (retries-- > 0);
> 
>-	return running;
>+	return -1;
> }
> 
> /* return the number of process es in our session, count only until limit */

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Attachments on bug 226997: 149299 | 153906 | 154301 | 156355