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From: Oscar Salvador <osalvador@suse.de>
To: akpm@linux-foundation.org
Cc: dan.j.williams@intel.com, david@redhat.com,
	pasha.tatashin@soleen.com, mhocko@suse.com,
	aneesh.kumar@linux.ibm.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, Oscar Salvador <osalvador@suse.de>
Subject: [PATCH v2 1/2] mm,sparse: Fix deactivate_section for early sections
Date: Wed, 17 Jul 2019 11:07:24 +0200	[thread overview]
Message-ID: <20190717090725.23618-2-osalvador@suse.de> (raw)
In-Reply-To: <20190717090725.23618-1-osalvador@suse.de>

deactivate_section checks whether a section is early or not
in order to either call free_map_bootmem() or depopulate_section_memmap().
Being the former for sections added at boot time, and the latter for
sections hotplugged.

The problem is that we zero section_mem_map, so the last early_section()
will always report false and the section will not be removed.

Fix this checking whether a section is early or not at function
entry.

Fixes: mmotm ("mm/sparsemem: Support sub-section hotplug")
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Dan Williams <dan.j.wiliams@intel.com>
---
 mm/sparse.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/mm/sparse.c b/mm/sparse.c
index 3267c4001c6d..1e224149aab6 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -738,6 +738,7 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
 	DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 };
 	DECLARE_BITMAP(tmp, SUBSECTIONS_PER_SECTION) = { 0 };
 	struct mem_section *ms = __pfn_to_section(pfn);
+	bool section_is_early = early_section(ms);
 	struct page *memmap = NULL;
 	unsigned long *subsection_map = ms->usage
 		? &ms->usage->subsection_map[0] : NULL;
@@ -772,7 +773,7 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
 	if (bitmap_empty(subsection_map, SUBSECTIONS_PER_SECTION)) {
 		unsigned long section_nr = pfn_to_section_nr(pfn);
 
-		if (!early_section(ms)) {
+		if (!section_is_early) {
 			kfree(ms->usage);
 			ms->usage = NULL;
 		}
@@ -780,7 +781,7 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
 		ms->section_mem_map = sparse_encode_mem_map(NULL, section_nr);
 	}
 
-	if (early_section(ms) && memmap)
+	if (section_is_early && memmap)
 		free_map_bootmem(memmap);
 	else
 		depopulate_section_memmap(pfn, nr_pages, altmap);
-- 
2.12.3


  reply	other threads:[~2019-07-17  9:07 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-17  9:07 [PATCH v2 0/2] Fixes for sub-section hotplug Oscar Salvador
2019-07-17  9:07 ` Oscar Salvador [this message]
2019-07-17  9:07 ` [PATCH v2 2/2] mm,memory_hotplug: Fix shrink_{zone,node}_span Oscar Salvador
2019-07-17 18:45   ` Dan Williams

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