From: Mel Gorman <mgorman@techsingularity.net>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Nicolas Saenz Julienne <nsaenzju@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
Vlastimil Babka <vbabka@suse.cz>,
Michal Hocko <mhocko@kernel.org>, Hugh Dickins <hughd@google.com>,
LKML <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>,
Mel Gorman <mgorman@techsingularity.net>
Subject: [PATCH 2/7] mm/page_alloc: Use only one PCP list for THP-sized allocations
Date: Mon, 13 Jun 2022 13:56:17 +0100 [thread overview]
Message-ID: <20220613125622.18628-3-mgorman@techsingularity.net> (raw)
In-Reply-To: <20220613125622.18628-1-mgorman@techsingularity.net>
The per_cpu_pages is cache-aligned on a standard x86-64 distribution
configuration but a later patch will add a new field which would push the
structure into the next cache line. Use only one list to store THP-sized
pages on the per-cpu list. This assumes that the vast majority of
THP-sized allocations are GFP_MOVABLE but even if it was another type, it
would not contribute to serious fragmentation that potentially causes a
later THP allocation failure. Align per_cpu_pages on the cacheline
boundary to ensure there is no false cache sharing.
After this patch, the structure sizing is;
struct per_cpu_pages {
int count; /* 0 4 */
int high; /* 4 4 */
int batch; /* 8 4 */
short int free_factor; /* 12 2 */
short int expire; /* 14 2 */
struct list_head lists[13]; /* 16 208 */
/* size: 256, cachelines: 4, members: 6 */
/* padding: 32 */
} __attribute__((__aligned__(64)));
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Tested-by: Minchan Kim <minchan@kernel.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---
include/linux/mmzone.h | 11 +++++++----
mm/page_alloc.c | 4 ++--
2 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index aab70355d64f..4e0352cc2fcb 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -355,15 +355,18 @@ enum zone_watermarks {
};
/*
- * One per migratetype for each PAGE_ALLOC_COSTLY_ORDER plus one additional
- * for pageblock size for THP if configured.
+ * One per migratetype for each PAGE_ALLOC_COSTLY_ORDER. One additional list
+ * for THP which will usually be GFP_MOVABLE. Even if it is another type,
+ * it should not contribute to serious fragmentation causing THP allocation
+ * failures.
*/
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
#define NR_PCP_THP 1
#else
#define NR_PCP_THP 0
#endif
-#define NR_PCP_LISTS (MIGRATE_PCPTYPES * (PAGE_ALLOC_COSTLY_ORDER + 1 + NR_PCP_THP))
+#define NR_LOWORDER_PCP_LISTS (MIGRATE_PCPTYPES * (PAGE_ALLOC_COSTLY_ORDER + 1))
+#define NR_PCP_LISTS (NR_LOWORDER_PCP_LISTS + NR_PCP_THP)
/*
* Shift to encode migratetype and order in the same integer, with order
@@ -389,7 +392,7 @@ struct per_cpu_pages {
/* Lists of pages, one per migrate type stored on the pcp-lists */
struct list_head lists[NR_PCP_LISTS];
-};
+} ____cacheline_aligned_in_smp;
struct per_cpu_zonestat {
#ifdef CONFIG_SMP
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 247fa7502199..febd97f4a2fc 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -653,7 +653,7 @@ static inline unsigned int order_to_pindex(int migratetype, int order)
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
if (order > PAGE_ALLOC_COSTLY_ORDER) {
VM_BUG_ON(order != pageblock_order);
- base = PAGE_ALLOC_COSTLY_ORDER + 1;
+ return NR_LOWORDER_PCP_LISTS;
}
#else
VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER);
@@ -667,7 +667,7 @@ static inline int pindex_to_order(unsigned int pindex)
int order = pindex / MIGRATE_PCPTYPES;
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
- if (order > PAGE_ALLOC_COSTLY_ORDER)
+ if (pindex == NR_LOWORDER_PCP_LISTS)
order = pageblock_order;
#else
VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER);
--
2.35.3
next prev parent reply other threads:[~2022-06-13 14:33 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-13 12:56 [PATCH v4 00/7] Drain remote per-cpu directly Mel Gorman
2022-06-13 12:56 ` [PATCH 1/7] mm/page_alloc: Add page->buddy_list and page->pcp_list Mel Gorman
2022-06-13 12:56 ` Mel Gorman [this message]
2022-06-13 12:56 ` [PATCH 3/7] mm/page_alloc: Split out buddy removal code from rmqueue into separate helper Mel Gorman
2022-06-13 12:56 ` [PATCH 4/7] mm/page_alloc: Remove mistaken page == NULL check in rmqueue Mel Gorman
2022-06-13 12:56 ` [PATCH 5/7] mm/page_alloc: Protect PCP lists with a spinlock Mel Gorman
2022-06-16 15:59 ` Vlastimil Babka
2022-06-13 12:56 ` [PATCH 6/7] mm/page_alloc: Remotely drain per-cpu lists Mel Gorman
2022-06-16 16:41 ` Vlastimil Babka
2022-06-13 12:56 ` [PATCH 7/7] mm/page_alloc: Replace local_lock with normal spinlock Mel Gorman
2022-06-15 22:43 ` Yu Zhao
[not found] ` <CGME20220615224855eucas1p1ea6d90c23ec9423dfe04b267f6dddd2a@eucas1p1.samsung.com>
2022-06-15 22:48 ` Marek Szyprowski
2022-06-15 23:04 ` Andrew Morton
2022-06-16 3:05 ` Yu Zhao
2022-06-17 7:55 ` Vlastimil Babka
2022-06-17 6:47 ` Marek Szyprowski
2022-06-21 9:21 ` Mel Gorman
2022-06-16 17:01 ` Vlastimil Babka
2022-06-16 21:07 ` Yu Zhao
2022-06-17 7:57 ` Vlastimil Babka
2022-06-21 9:27 ` Mel Gorman
2022-06-21 9:26 ` Mel Gorman
2022-06-17 9:39 ` Nicolas Saenz Julienne
2022-06-21 9:29 ` Mel Gorman
2022-06-21 9:31 ` Nicolas Saenz Julienne
2022-07-03 9:44 ` [mm/page_alloc] 2bd8eec68f: BUG:sleeping_function_called_from_invalid_context_at_mm/gup.c kernel test robot
2022-07-03 20:22 ` Andrew Morton
2022-07-05 13:51 ` Oliver Sang
2022-07-06 9:55 ` Mel Gorman
2022-07-06 11:53 ` Mel Gorman
2022-07-06 14:21 ` Oliver Sang
2022-07-06 14:52 ` Mel Gorman
2022-07-07 8:22 ` Oliver Sang
2022-07-06 14:25 ` Oliver Sang
2022-07-06 14:53 ` Mel Gorman
2022-07-07 21:55 ` Vlastimil Babka
2022-07-08 10:56 ` Mel Gorman
2022-07-12 5:04 ` Oliver Sang
2022-06-24 12:54 [PATCH v5 00/7] Drain remote per-cpu directly Mel Gorman
2022-06-24 12:54 ` [PATCH 2/7] mm/page_alloc: Use only one PCP list for THP-sized allocations Mel Gorman
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