From: Oscar Salvador <osalvador@techadventures.net>
To: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@suse.com>, Vlastimil Babka <vbabka@suse.cz>,
iamjoonsoo.kim@lge.com, aaron.lu@intel.com,
LKML <linux-kernel@vger.kernel.org>,
Linux Memory Management List <linux-mm@kvack.org>,
osalvador@suse.de
Subject: Re: [PATCH 3/3] mm/page_alloc: Split context in free_area_init_node
Date: Thu, 19 Jul 2018 09:35:31 +0200 [thread overview]
Message-ID: <20180719073531.GA8750@techadventures.net> (raw)
In-Reply-To: <CAGM2reY8ODmr=u4bsCrdEX3f-c6NkSuKuEcXowRy=SkuMppjiw@mail.gmail.com>
On Wed, Jul 18, 2018 at 10:34:19AM -0400, Pavel Tatashin wrote:
> On Wed, Jul 18, 2018 at 8:47 AM <osalvador@techadventures.net> wrote:
> >
> > From: Oscar Salvador <osalvador@suse.de>
> >
> > If free_area_init_node gets called from memhotplug code,
> > we do not need to call calculate_node_totalpages(),
> > as the node has no pages.
>
> I am not positive this is safe. Some pgdat fields in
> calculate_node_totalpages() are set. Even if those fields are always
> set to zeros, pgdat may be reused (i.e. node went offline and later
> came back online), so we might still need to set those fields to
> zeroes.
>
You are right, I do not know why, but I thought that we were zeroing pgdat struct
before getting in the function.
I will leave that part out.
Since we only should care about deferred pfns during the boot, maybe we can change
it to something like:
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 70fe4c80643f..89fc8f4240ca 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6381,6 +6381,21 @@ static void __ref alloc_node_mem_map(struct pglist_data *pgdat)
static void __ref alloc_node_mem_map(struct pglist_data *pgdat) { }
#endif /* CONFIG_FLAT_NODE_MEM_MAP */
+#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
+static void pgdat_set_deferred_range(pg_data_t *pgdat)
+{
+ /*
+ * We start only with one section of pages, more pages are added as
+ * needed until the rest of deferred pages are initialized.
+ */
+ pgdat->static_init_pgcnt = min_t(unsigned long, PAGES_PER_SECTION,
+ pgdat->node_spanned_pages);
+ pgdat->first_deferred_pfn = ULONG_MAX;
+}
+#else
+static void pgdat_set_deferred_range(pg_data_t *pgdat) {}
+#endif
+
void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
unsigned long node_start_pfn, unsigned long *zholes_size)
{
@@ -6402,20 +6417,14 @@ void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
#else
start_pfn = node_start_pfn;
#endif
- calculate_node_totalpages(pgdat, start_pfn, end_pfn,
- zones_size, zholes_size);
+ calculate_node_totalpages(pgdat, start_pfn, end_pfn,
+ zones_size, zholes_size);
alloc_node_mem_map(pgdat);
-#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
- /*
- * We start only with one section of pages, more pages are added as
- * needed until the rest of deferred pages are initialized.
- */
- pgdat->static_init_pgcnt = min_t(unsigned long, PAGES_PER_SECTION,
- pgdat->node_spanned_pages);
- pgdat->first_deferred_pfn = ULONG_MAX;
-#endif
+ if (system_state == SYSTEM_BOOTING)
+ pgdat_set_deferred_range(pgdat);
+
free_area_init_core(pgdat);
}
Thanks
--
Oscar Salvador
SUSE L3
prev parent reply other threads:[~2018-07-19 7:35 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-18 12:47 [PATCH 0/3] Re-structure free_area_init_node / free_area_init_core osalvador
2018-07-18 12:47 ` [PATCH 1/3] mm/page_alloc: Move ifdefery out of free_area_init_core osalvador
2018-07-18 13:37 ` Michal Hocko
2018-07-18 14:11 ` Pavel Tatashin
2018-07-18 15:15 ` Oscar Salvador
2018-07-19 12:19 ` Oscar Salvador
2018-07-19 13:18 ` Pavel Tatashin
2018-07-18 12:47 ` [PATCH 2/3] mm/page_alloc: Refactor free_area_init_core osalvador
2018-07-18 13:36 ` Michal Hocko
2018-07-18 14:12 ` Oscar Salvador
2018-07-18 15:11 ` Oscar Salvador
2018-07-18 12:47 ` [PATCH 3/3] mm/page_alloc: Split context in free_area_init_node osalvador
2018-07-18 14:34 ` Pavel Tatashin
2018-07-19 7:35 ` Oscar Salvador [this message]
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