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authorPavel Tatashin <pasha.tatashin@oracle.com>2018-04-06 02:23:00 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-06 07:36:25 +0300
commitd0dc12e86b3197a14a908d4fe7cb35b73dda82b5 (patch)
tree28bd3b5c716e3e1c04fab511c3a41033bdc85993 /mm/page_alloc.c
parentfc44f7f9231a73821fc858f5bc48883a9e78f6de (diff)
downloadlinux-d0dc12e86b3197a14a908d4fe7cb35b73dda82b5.tar.xz
mm/memory_hotplug: optimize memory hotplug
During memory hotplugging we traverse struct pages three times: 1. memset(0) in sparse_add_one_section() 2. loop in __add_section() to set do: set_page_node(page, nid); and SetPageReserved(page); 3. loop in memmap_init_zone() to call __init_single_pfn() This patch removes the first two loops, and leaves only loop 3. All struct pages are initialized in one place, the same as it is done during boot. The benefits: - We improve memory hotplug performance because we are not evicting the cache several times and also reduce loop branching overhead. - Remove condition from hotpath in __init_single_pfn(), that was added in order to fix the problem that was reported by Bharata in the above email thread, thus also improve performance during normal boot. - Make memory hotplug more similar to the boot memory initialization path because we zero and initialize struct pages only in one function. - Simplifies memory hotplug struct page initialization code, and thus enables future improvements, such as multi-threading the initialization of struct pages in order to improve hotplug performance even further on larger machines. [pasha.tatashin@oracle.com: v5] Link: http://lkml.kernel.org/r/20180228030308.1116-7-pasha.tatashin@oracle.com Link: http://lkml.kernel.org/r/20180215165920.8570-7-pasha.tatashin@oracle.com Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Baoquan He <bhe@redhat.com> Cc: Bharata B Rao <bharata@linux.vnet.ibm.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Steven Sistare <steven.sistare@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_alloc.c')
-rw-r--r--mm/page_alloc.c28
1 files changed, 10 insertions, 18 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3183eb2f579c..a3e2ba4f76bb 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1143,10 +1143,9 @@ static void free_one_page(struct zone *zone,
}
static void __meminit __init_single_page(struct page *page, unsigned long pfn,
- unsigned long zone, int nid, bool zero)
+ unsigned long zone, int nid)
{
- if (zero)
- mm_zero_struct_page(page);
+ mm_zero_struct_page(page);
set_page_links(page, zone, nid, pfn);
init_page_count(page);
page_mapcount_reset(page);
@@ -1160,12 +1159,6 @@ static void __meminit __init_single_page(struct page *page, unsigned long pfn,
#endif
}
-static void __meminit __init_single_pfn(unsigned long pfn, unsigned long zone,
- int nid, bool zero)
-{
- return __init_single_page(pfn_to_page(pfn), pfn, zone, nid, zero);
-}
-
#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
static void __meminit init_reserved_page(unsigned long pfn)
{
@@ -1184,7 +1177,7 @@ static void __meminit init_reserved_page(unsigned long pfn)
if (pfn >= zone->zone_start_pfn && pfn < zone_end_pfn(zone))
break;
}
- __init_single_pfn(pfn, zid, nid, true);
+ __init_single_page(pfn_to_page(pfn), pfn, zid, nid);
}
#else
static inline void init_reserved_page(unsigned long pfn)
@@ -1501,7 +1494,7 @@ static unsigned long __init deferred_init_pages(int nid, int zid,
} else {
page++;
}
- __init_single_page(page, pfn, zid, nid, true);
+ __init_single_page(page, pfn, zid, nid);
nr_pages++;
}
return (nr_pages);
@@ -5434,6 +5427,7 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
pg_data_t *pgdat = NODE_DATA(nid);
unsigned long pfn;
unsigned long nr_initialised = 0;
+ struct page *page;
#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
struct memblock_region *r = NULL, *tmp;
#endif
@@ -5486,6 +5480,11 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
#endif
not_early:
+ page = pfn_to_page(pfn);
+ __init_single_page(page, pfn, zone, nid);
+ if (context == MEMMAP_HOTPLUG)
+ SetPageReserved(page);
+
/*
* Mark the block movable so that blocks are reserved for
* movable at startup. This will force kernel allocations
@@ -5502,15 +5501,8 @@ not_early:
* because this is done early in sparse_add_one_section
*/
if (!(pfn & (pageblock_nr_pages - 1))) {
- struct page *page = pfn_to_page(pfn);
-
- __init_single_page(page, pfn, zone, nid,
- context != MEMMAP_HOTPLUG);
set_pageblock_migratetype(page, MIGRATE_MOVABLE);
cond_resched();
- } else {
- __init_single_pfn(pfn, zone, nid,
- context != MEMMAP_HOTPLUG);
}
}
}