The patch titled
Subject: mm/sparse.c: add a static variable nr_present_sections
has been removed from the -mm tree. Its filename was
mm-sparse-add-a-static-variable-nr_present_sections.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Baoquan He <bhe@xxxxxxxxxx>
Subject: mm/sparse.c: add a static variable nr_present_sections
Patch series "mm/sparse: Optimize memmap allocation during sparse_init()",
v6.
In sparse_init(), two temporary pointer arrays, usemap_map and map_map are
allocated with the size of NR_MEM_SECTIONS. They are used to store each
memory section's usemap and mem map if marked as present. In 5-level
paging mode, this will cost 512M memory though they will be released at
the end of sparse_init(). System with few memory, like kdump kernel which
usually only has about 256M, will fail to boot because of allocation
failure if CONFIG_X86_5LEVEL=y.
In this patchset, optimize the memmap allocation code to only use
usemap_map and map_map with the size of nr_present_sections. This makes
kdump kernel boot up with normal crashkernel='' setting when
CONFIG_X86_5LEVEL=y.
This patch (of 5):
nr_present_sections is used to record how many memory sections are marked
as present during system boot up, and will be used in the later patch.
Link: http://lkml.kernel.org/r/20180228032657.32385-2-bhe@xxxxxxxxxx
Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
Acked-by: Dave Hansen <dave.hansen@xxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>
Cc: Pasha Tatashin <Pavel.Tatashin@xxxxxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Pankaj Gupta <pagupta@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/sparse.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/mm/sparse.c~mm-sparse-add-a-static-variable-nr_present_sections
+++ a/mm/sparse.c
@@ -200,6 +200,12 @@ static inline int next_present_section_n
(section_nr <= __highest_present_section_nr)); \
section_nr = next_present_section_nr(section_nr))
+/*
+ * Record how many memory sections are marked as present
+ * during system bootup.
+ */
+static int __initdata nr_present_sections;
+
/* Record a memory area against a node. */
void __init memory_present(int nid, unsigned long start, unsigned long end)
{
@@ -229,6 +235,7 @@ void __init memory_present(int nid, unsi
ms->section_mem_map = sparse_encode_early_nid(nid) |
SECTION_IS_ONLINE;
section_mark_present(ms);
+ nr_present_sections++;
}
}
}
_
Patches currently in -mm which might be from bhe@xxxxxxxxxx are
