[PATCH] memtools: add lsmemregions command

* [PATCH] memtools: add lsmemregions command
@ 2025-09-26 23:04 Leo Sandoval via Grub-devel
  2025-09-27 19:29 ` Andrew Hamilton
  2025-10-16 18:40 ` Daniel Kiper
  0 siblings, 2 replies; 6+ messages in thread
From: Leo Sandoval via Grub-devel @ 2025-09-26 23:04 UTC (permalink / raw)
  To: grub-devel; +Cc: Leo Sandoval

Prints memory regions general information including size, number of
blocks, total free and total allocated memory per region. The reason
behind is to have a tool that shows general information about regions
and how fragmented the memory is at some particular time.

Below is an example showing how this tool before and after memory
stress.

    grub> lsmemregions

    Region 0x78f6e000 (size 33554368 blocks 1048574 free 27325472 alloc 6232768)

    > stress_big_allocations
    ...

    grub> lsmemregions

    Region 0x7af8e000 (size 4032 blocks 126 free 2720 alloc 1312)
    Region 0x80c000 (size 81856 blocks 2558 free 81856 alloc 0)
    Region 0x7d165000 (size 167872 blocks 5246 free 167872 alloc 0)
    Region 0x7d0bf000 (size 655296 blocks 20478 free 655296 alloc 0)
    Region 0x7ee00000 (size 1331136 blocks 41598 free 1331136 alloc 0)
    Region 0x100000 (size 7385024 blocks 230782 free 7385024 alloc 0)
    Region 0x7af95000 (size 25382848 blocks 793214 free 25382848 alloc 0)
    Region 0x1780000 (size 2038357952 blocks 63698686 free 2077517536 alloc 5445568)

Signed-off-by: Leo Sandoval <lsandova@redhat.com>
---
 grub-core/commands/memtools.c | 17 +++++++++++++++-
 grub-core/kern/mm.c           | 37 +++++++++++++++++++++++++++++++++++
 include/grub/mm.h             |  1 +
 3 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/grub-core/commands/memtools.c b/grub-core/commands/memtools.c
index ae0a9bec35..0829949dbc 100644
--- a/grub-core/commands/memtools.c
+++ b/grub-core/commands/memtools.c
@@ -53,6 +53,18 @@ grub_cmd_lsfreemem (grub_command_t cmd __attribute__ ((unused)),
   return 0;
 }
 
+static grub_err_t
+grub_cmd_lsmemregions (grub_command_t cmd __attribute__ ((unused)),
+		 int argc __attribute__ ((unused)),
+		 char **args __attribute__ ((unused)))
+
+{
+#ifndef GRUB_MACHINE_EMU
+  grub_mm_dump_regions ();
+#endif
+
+  return 0;
+}
 
 static grub_err_t
 grub_cmd_stress_big_allocs (grub_command_t cmd __attribute__ ((unused)),
@@ -132,7 +144,7 @@ grub_cmd_stress_big_allocs (grub_command_t cmd __attribute__ ((unused)),
   return GRUB_ERR_NONE;
 }
 
-static grub_command_t cmd_lsmem, cmd_lsfreemem, cmd_sba;
+static grub_command_t cmd_lsmem, cmd_lsfreemem, cmd_lsmemregions, cmd_sba;
 
 GRUB_MOD_INIT (memtools)
 {
@@ -140,6 +152,8 @@ GRUB_MOD_INIT (memtools)
 				     0, N_("List free and allocated memory blocks."));
   cmd_lsfreemem = grub_register_command ("lsfreemem", grub_cmd_lsfreemem,
 					 0, N_("List free memory blocks."));
+  cmd_lsmemregions = grub_register_command ("lsmemregions", grub_cmd_lsmemregions,
+					 0, N_("List memory regions."));
   cmd_sba = grub_register_command ("stress_big_allocs", grub_cmd_stress_big_allocs,
 				   0, N_("Stress test large allocations."));
 }
@@ -148,5 +162,6 @@ GRUB_MOD_FINI (memtools)
 {
   grub_unregister_command (cmd_lsmem);
   grub_unregister_command (cmd_lsfreemem);
+  grub_unregister_command (cmd_lsmemregions);
   grub_unregister_command (cmd_sba);
 }
diff --git a/grub-core/kern/mm.c b/grub-core/kern/mm.c
index 027a25cd1f..8112af5a69 100644
--- a/grub-core/kern/mm.c
+++ b/grub-core/kern/mm.c
@@ -786,6 +786,43 @@ grub_mm_dump (unsigned lineno)
   grub_printf ("\n");
 }
 
+void
+grub_mm_dump_regions (void)
+{
+  grub_mm_region_t r;
+  grub_mm_header_t p;
+  grub_size_t num_blocks, sum_free, sum_alloc;
+
+  for (r = grub_mm_base; r; r = r->next)
+    {
+      num_blocks = 0;
+      sum_free = 0;
+      sum_alloc = 0;
+
+      for (p = (grub_mm_header_t) ALIGN_UP ((grub_addr_t) (r + 1),
+					    GRUB_MM_ALIGN);
+	   (grub_addr_t) p < (grub_addr_t) (r+1) + r->size;
+	   p++, num_blocks++)
+	{
+	  switch (p->magic)
+	    {
+	    case GRUB_MM_FREE_MAGIC:
+	      sum_free += p->size;
+	      break;
+	    case GRUB_MM_ALLOC_MAGIC:
+	      sum_alloc += p->size;
+	      break;
+	    }
+	}
+
+      grub_printf ("Region %p (size %" PRIuGRUB_SIZE " blocks %" PRIuGRUB_SIZE " free %" PRIuGRUB_SIZE " alloc %" PRIuGRUB_SIZE ")\n\n",
+		   r, r->size, num_blocks, sum_free << GRUB_MM_ALIGN_LOG2, sum_alloc << GRUB_MM_ALIGN_LOG2);
+
+    }
+
+  grub_printf ("\n");
+}
+
 void *
 grub_debug_calloc (const char *file, int line, grub_size_t nmemb, grub_size_t size)
 {
diff --git a/include/grub/mm.h b/include/grub/mm.h
index 51ec0b8f9b..06956484c6 100644
--- a/include/grub/mm.h
+++ b/include/grub/mm.h
@@ -100,6 +100,7 @@ extern int EXPORT_VAR(grub_mm_debug);
 
 void EXPORT_FUNC(grub_mm_dump_free) (void);
 void EXPORT_FUNC(grub_mm_dump) (unsigned lineno);
+void EXPORT_FUNC(grub_mm_dump_regions) (void);
 
 #define grub_calloc(nmemb, size)	\
   grub_debug_calloc (GRUB_FILE, __LINE__, nmemb, size)
-- 
2.50.1


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