78 lines
2.9 KiB
Diff
78 lines
2.9 KiB
Diff
I have a version of free I wrote for BusyBox that uses sysinfo (rather then
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/proc) to get its information. Under 2.2.x it reports normal stuff, i.e.
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[andersen@dillweed busybox]$ ./free
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total used free shared buffers
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Mem: 127800 124268 3532 16956 7544
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Swap: 128516 13584 114932
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Total: 256316 137852 118464
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while under 2.2.0-test1-ac7 it reports wierd numbers (~ #/4096)
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[andersen@dillweed busybox]$ ./free
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total used free shared buffers
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Mem: 30 11 19 0 1
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Swap: 31 0 31
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Total: 61 11 50
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After investigating the problem, it turns out that somewhere during 2.3.x the
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values for memory stored in struct sysinfo changed from being stored as bytes
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to being units of PAGE_SIZE, but kernel/info.c was never updated to reflect
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this change in definition.
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Breaking free isn't that big of a deal, but I also use sysinfo in init to check
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that the box has enough ram from within the init process (and no, mounting
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/proc from within init and reading /proc/meminfo is not a good solution.
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BusyBox is often used in embedded systems where /proc is not compiled in).
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The following patch reinstates the traditional sysinfo(2) interface by
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returning bytes (not units of PAGE_SIZE) for memory values.
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An additional patch suggestion (not included here) would be to eliminate the
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supurfluous "mem_unit" variable from struct_sysinfo in include/linux/kernel.h
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and arch/*/mm/init.c.
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-Erik
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--
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Erik B. Andersen Web: http://www.xmission.com/~andersen/
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email: andersee@debian.org
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--This message was written using 73% post-consumer electrons--
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--- linux/kernel/info.c.orig Mon Aug 23 12:15:53 1999
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+++ linux/kernel/info.c Sun Jun 4 01:13:11 2000
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@@ -2,6 +2,8 @@
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* linux/kernel/info.c
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*
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* Copyright (C) 1992 Darren Senn
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+ * Fixed to once again return bytes instead of page counts,
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+ * June 2000, by Erik Andersen <andersee@debian.org>
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*/
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/* This implements the sysinfo() system call */
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@@ -10,7 +12,6 @@
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#include <linux/unistd.h>
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#include <linux/swap.h>
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#include <linux/smp_lock.h>
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-
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#include <asm/uaccess.h>
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asmlinkage long sys_sysinfo(struct sysinfo *info)
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@@ -31,6 +32,17 @@
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si_meminfo(&val);
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si_swapinfo(&val);
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+
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+ /* These are in units of PAGE_SIZE, but this interface
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+ * has always returned bytes. Make it return bytes */
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+ val.totalram*=PAGE_SIZE;
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+ val.freeram*=PAGE_SIZE;
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+ val.sharedram*=PAGE_SIZE;
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+ val.bufferram*=PAGE_SIZE;
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+ val.totalswap*=PAGE_SIZE;
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+ val.freeswap*=PAGE_SIZE;
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+ val.totalhigh*=PAGE_SIZE;
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+ val.freehigh*=PAGE_SIZE;
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if (copy_to_user(info, &val, sizeof(struct sysinfo)))
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return -EFAULT;
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