[Crash-utility] [PATCH 5/5] memory: kmem option to skip free pages

[Yu Zhao]

---
 help.c   |  4 +++-
 memory.c | 17 ++++++++++++++---
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/help.c b/help.c
index ffc8aeb..0f1508d 100644
--- a/help.c
+++ b/help.c
@@ -5541,7 +5541,7 @@ NULL
 char *help_kmem[] = {
 "kmem",
 "kernel memory",
-"[-f|-F|-p|-c|-C|-i|-s|-S|-v|-V|-n|-z|-o|-h|-k] [slab] [[-P] address]\n"
+"[-f|-F|-p|-c|-C|-i|-s|-S|-v|-V|-n|-z|-o|-h|-k|-r] [slab] [[-P] address]\n"
 "       [-g [flags]] [-I slab[,slab]]",
 "  This command displays information about the use of kernel memory.\n",
 "        -f  displays the contents of the system free memory headers.",
@@ -5576,6 +5576,8 @@ char *help_kmem[] = {
 "            caused by misuse of compound pages (e.g. free with wrong order).",
 "            When an error is found, the compound order will be shown as -1.",
 "            Only works when -p is used without an address.",
+"        -r  only print used pages (i.e. the page count is not zero).",
+"            Only works when -p is used without an address.",
 "     flags  when used with -g, translates all bits in this hexadecimal page",
 "            structure flags value into its enumerator values.",
 "      slab  when used with -s or -S, limits the command to only the slab cache",
diff --git a/memory.c b/memory.c
index 43ceff7..a1ef59a 100644
--- a/memory.c
+++ b/memory.c
@@ -4425,6 +4425,7 @@ get_task_mem_usage(ulong task, struct task_mem_usage *tm)
 #define SLAB_BITFIELD          (ADDRESS_SPECIFIED << 25)
 
 #define VERIFY_COMPOUND_PAGES	(1 << 0)
+#define SKIP_FREE_PAGES		(1 << 1)
 
 #define GET_ALL \
 	(GET_SHARED_PAGES|GET_TOTALRAM_PAGES|GET_BUFFERS_PAGES|GET_SLAB_PAGES)
@@ -4436,7 +4437,7 @@ cmd_kmem(void)
 	int c;
 	int sflag, Sflag, pflag, fflag, Fflag, vflag, zflag, oflag, gflag; 
 	int nflag, cflag, Cflag, iflag, lflag, Lflag, Pflag, Vflag, hflag;
-	int kflag;
+	int kflag, rflag;
 	struct meminfo meminfo;
 	ulonglong value[MAXARGS];
 	char buf[BUFSIZE];
@@ -4446,12 +4447,12 @@ cmd_kmem(void)
 	spec_addr = 0;
         sflag =	Sflag = pflag = fflag = Fflag = Pflag = zflag = oflag = 0;
 	vflag = Cflag = cflag = iflag = nflag = lflag = Lflag = Vflag = 0;
-	gflag = hflag = kflag = 0;
+	gflag = hflag = kflag = rflag = 0;
 	escape = FALSE;
 	BZERO(&meminfo, sizeof(struct meminfo));
 	BZERO(&value[0], sizeof(ulonglong)*MAXARGS);
 
-        while ((c = getopt(argcnt, args, "gI:sSFfpkvczCinl:L:PVoh")) != EOF) {
+        while ((c = getopt(argcnt, args, "gI:sSFfpkrvczCinl:L:PVoh")) != EOF) {
                 switch(c)
 		{
 		case 'V':
@@ -4560,6 +4561,10 @@ cmd_kmem(void)
 			kflag = 1;
 			break;
 
+		case 'r':
+			rflag = 1;
+			break;
+
 		default:
 			argerrs++;
 			break;
@@ -4730,6 +4735,8 @@ cmd_kmem(void)
 	if (pflag == 1) {
 		if (kflag)
 			meminfo.extra_flags |= VERIFY_COMPOUND_PAGES;
+		if (rflag)
+			meminfo.extra_flags |= SKIP_FREE_PAGES;
 		dump_mem_map(&meminfo);
 	}
 
@@ -5228,6 +5235,8 @@ dump_mem_map_SPARSEMEM(struct meminfo *mi)
 			if (SIZE(page_flags) == 4)
 				flags &= 0xffffffff;
 			count = UINT(pcache + OFFSET(page_count));
+			if (!count && (mi->extra_flags & SKIP_FREE_PAGES))
+				continue;
 
 	                switch (mi->flags)
 			{
@@ -5677,6 +5686,8 @@ dump_mem_map(struct meminfo *mi)
 			if (SIZE(page_flags) == 4)
 				flags &= 0xffffffff;
 			count = UINT(pcache + OFFSET(page_count));
+			if (!count && (mi->extra_flags & SKIP_FREE_PAGES))
+				continue;
 
 	                switch (mi->flags)
 			{
-- 
2.2.0.rc0.207.ga3a616c