Date: Mon,  8 Dec 2025 14:01:16 +0530
From: Shivang Upadhyay <shivangu@linux.ibm.com>
Subject: [Crash-utility] [PATCH v4] make the MAX_MALLOC_BUFS
        customizable
To: devel@lists.crash-utility.osci.io
Cc: shivangu@linux.ibm.com, lijiang@redhat.com
Message-ID: <20251208083116.436292-1-shivangu@linux.ibm.com>

the default (and minimum) value of MAX_MALLOC_BUFS is 3072, but can be
changed with command line with flag `--max-malloc-bufs`.

Signed-off-by: Shivang Upadhyay <shivangu@linux.ibm.com>
---
 defs.h  | 8 ++++++++
 main.c  | 4 ++++
 tools.c | 9 ++++++---
 3 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/defs.h b/defs.h
index ab4aee8..f3de0e5 100644
--- a/defs.h
+++ b/defs.h
@@ -188,6 +188,13 @@
 #define HIST_BLKSIZE  (4096)

 static inline int string_exists(char *s) { return (s ? TRUE : FALSE); }
+
+static inline int max(int a, int b) {
+       if (a > b)
+               return a;
+       return b;
+}
+
 #define STREQ(A, B)      (string_exists((char *)A) && string_exists((char *)B) && \
        (strcmp((char *)(A), (char *)(B)) == 0))
 #define STRNEQ(A, B)     (string_exists((char *)A) && string_exists((char *)B) && \
@@ -5608,6 +5615,7 @@ void exec_args_input_file(struct command_table_entry *, struct args_input_file *
 /*
  *  tools.c
  */
+extern int MAX_MALLOC_BUFS;
 FILE *set_error(char *);
 int __error(int, char *, ...);
 #define error __error               /* avoid conflict with gdb error() */
diff --git a/main.c b/main.c
index 71bcc15..247779c 100644
--- a/main.c
+++ b/main.c
@@ -46,6 +46,7 @@ static struct option long_options[] = {
        {"version", 0, 0, 0},
        {"buildinfo", 0, 0, 0},
         {"cpus", required_argument, 0, 0},
+        {"max-malloc-bufs", required_argument, 0, 0},
         {"no_ikconfig", 0, 0, 0},
         {"hyper", 0, 0, 0},
        {"p2m_mfn", required_argument, 0, 0},
@@ -163,6 +164,9 @@ main(int argc, char **argv)
                        else if (STREQ(long_options[option_index].name, "cpus"))
                                kt->cpus_override = optarg;

+                       else if (STREQ(long_options[option_index].name, "max-malloc-bufs"))
+                               MAX_MALLOC_BUFS = max(MAX_MALLOC_BUFS, atoi(optarg));
+
                        else if (STREQ(long_options[option_index].name, "hyper"))
                                pc->flags |= XEN_HYPER;

diff --git a/tools.c b/tools.c
index a9ad18d..69250c4 100644
--- a/tools.c
+++ b/tools.c
@@ -5698,7 +5698,7 @@ ll_power(long long base, long long exp)
 #define B32K (4)

 #define SHARED_BUF_SIZES  (B32K+1)
-#define MAX_MALLOC_BUFS   (2000)
+int MAX_MALLOC_BUFS  = 3072; /* can be changed from command line args */
 #define MAX_CACHE_SIZE    (KILOBYTES(32))

 struct shared_bufs {
@@ -5723,7 +5723,7 @@ struct shared_bufs {
         long buf_8K_ovf;
         long buf_32K_ovf;
        int buf_inuse[SHARED_BUF_SIZES];
-       char *malloc_bp[MAX_MALLOC_BUFS];
+       char **malloc_bp;
        long smallest;
        long largest;
        long embedded;
@@ -5744,6 +5744,7 @@ buf_init(void)

        bp->smallest = 0x7fffffff;
        bp->total = 0.0;
+       bp->malloc_bp = (char**) calloc(MAX_MALLOC_BUFS * sizeof(char*), 1);

 #ifdef VALGRIND
        VALGRIND_MAKE_MEM_NOACCESS(&bp->buf_1K, sizeof(bp->buf_1K));
@@ -6130,7 +6131,9 @@ getbuf(long reqsize)
        dump_shared_bufs();

        return ((char *)(long)
-               error(FATAL, "cannot allocate any more memory!\n"));
+               error(FATAL, "cannot allocate any more memory!\n"
+                               "try increasing --max-malloc-bufs (current  value : %d)\n",
+                               MAX_MALLOC_BUFS));
 }

 /*
--
2.52.0