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Message-Id: <20220511081207.132034-1-vvghjk1234@gmail.com>
Date: Wed, 11 May 2022 17:12:07 +0900
From: Wonhyuk Yang <vvghjk1234@...il.com>
To: Mel Gorman <mgorman@...e.de>, Steven Rostedt <rostedt@...dmis.org>,
Ingo Molnar <mingo@...hat.com>,
Andrew Morton <akpm@...ux-foundation.org>
Cc: Wonhyuk Yang <vvghjk1234@...il.com>,
Baik Song An <bsahn@...i.re.kr>,
Hong Yeon Kim <kimhy@...i.re.kr>,
Taeung Song <taeung@...llinux.co.kr>, linuxgeek@...uxgeek.io,
linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: [PATCH] mm/page_alloc: Fix tracepoint mm_page_alloc_zone_locked()
Currently, trace point mm_page_alloc_zone_locked() doesn't show
correct information.
First, when alloc_flag has ALLOC_HARDER/ALLOC_CMA, page can
be allocated from MIGRATE_HIGHATOMIC/MIGRATE_CMA. Nevertheless,
tracepoint use requested migration type not MIGRATE_HIGHATOMIC and
MIGRATE_CMA.
Second, after Commit 44042b4498728 ("mm/page_alloc: allow high-order
pages to be stored on the per-cpu lists") percpu-list can store
high order pages. But trace point determine whether it is a refiil
of percpu-list by comparing requested order and 0.
To handle these problems, use cached migration type by
get_pcppage_migratetype() instead of requested migration type.
Then, make mm_page_alloc_zone_locked() be called only two contexts
(rmqueue_bulk, rmqueue). With a new argument called percpu_refill,
it can show whether it is a refill of percpu-list correctly.
Cc: Baik Song An <bsahn@...i.re.kr>
Cc: Hong Yeon Kim <kimhy@...i.re.kr>
Cc: Taeung Song <taeung@...llinux.co.kr>
Cc: linuxgeek@...uxgeek.io
Signed-off-by: Wonhyuk Yang <vvghjk1234@...il.com>
---
include/trace/events/kmem.h | 14 +++++++++-----
mm/page_alloc.c | 18 +++++++++---------
2 files changed, 18 insertions(+), 14 deletions(-)
diff --git a/include/trace/events/kmem.h b/include/trace/events/kmem.h
index ddc8c944f417..f89fb3afcd46 100644
--- a/include/trace/events/kmem.h
+++ b/include/trace/events/kmem.h
@@ -229,20 +229,23 @@ TRACE_EVENT(mm_page_alloc,
DECLARE_EVENT_CLASS(mm_page,
- TP_PROTO(struct page *page, unsigned int order, int migratetype),
+ TP_PROTO(struct page *page, unsigned int order, int migratetype,
+ int percpu_refill),
- TP_ARGS(page, order, migratetype),
+ TP_ARGS(page, order, migratetype, percpu_refill),
TP_STRUCT__entry(
__field( unsigned long, pfn )
__field( unsigned int, order )
__field( int, migratetype )
+ __field( int, percpu_refill )
),
TP_fast_assign(
__entry->pfn = page ? page_to_pfn(page) : -1UL;
__entry->order = order;
__entry->migratetype = migratetype;
+ __entry->percpu_refill = percpu_refill;
),
TP_printk("page=%p pfn=0x%lx order=%u migratetype=%d percpu_refill=%d",
@@ -250,14 +253,15 @@ DECLARE_EVENT_CLASS(mm_page,
__entry->pfn != -1UL ? __entry->pfn : 0,
__entry->order,
__entry->migratetype,
- __entry->order == 0)
+ __entry->percpu_refill)
);
DEFINE_EVENT(mm_page, mm_page_alloc_zone_locked,
- TP_PROTO(struct page *page, unsigned int order, int migratetype),
+ TP_PROTO(struct page *page, unsigned int order, int migratetype,
+ int percpu_refill),
- TP_ARGS(page, order, migratetype)
+ TP_ARGS(page, order, migratetype, percpu_refill)
);
TRACE_EVENT(mm_page_pcpu_drain,
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 0e42038382c1..0351808322ba 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2999,7 +2999,7 @@ __rmqueue(struct zone *zone, unsigned int order, int migratetype,
zone_page_state(zone, NR_FREE_PAGES) / 2) {
page = __rmqueue_cma_fallback(zone, order);
if (page)
- goto out;
+ return page;
}
}
retry:
@@ -3012,9 +3012,6 @@ __rmqueue(struct zone *zone, unsigned int order, int migratetype,
alloc_flags))
goto retry;
}
-out:
- if (page)
- trace_mm_page_alloc_zone_locked(page, order, migratetype);
return page;
}
@@ -3028,6 +3025,7 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order,
int migratetype, unsigned int alloc_flags)
{
int i, allocated = 0;
+ int mt;
/*
* local_lock_irq held so equivalent to spin_lock_irqsave for
@@ -3055,7 +3053,9 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order,
*/
list_add_tail(&page->lru, list);
allocated++;
- if (is_migrate_cma(get_pcppage_migratetype(page)))
+ mt = get_pcppage_migratetype(page);
+ trace_mm_page_alloc_zone_locked(page, order, mt, true);
+ if (is_migrate_cma(mt))
__mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
-(1 << order));
}
@@ -3704,6 +3704,7 @@ struct page *rmqueue(struct zone *preferred_zone,
{
unsigned long flags;
struct page *page;
+ int mt;
if (likely(pcp_allowed_order(order))) {
/*
@@ -3735,16 +3736,15 @@ struct page *rmqueue(struct zone *preferred_zone,
*/
if (order > 0 && alloc_flags & ALLOC_HARDER) {
page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC);
- if (page)
- trace_mm_page_alloc_zone_locked(page, order, migratetype);
}
if (!page) {
page = __rmqueue(zone, order, migratetype, alloc_flags);
if (!page)
goto failed;
}
- __mod_zone_freepage_state(zone, -(1 << order),
- get_pcppage_migratetype(page));
+ mt = get_pcppage_migratetype(page);
+ trace_mm_page_alloc_zone_locked(page, order, mt, false);
+ __mod_zone_freepage_state(zone, -(1 << order), mt);
spin_unlock_irqrestore(&zone->lock, flags);
} while (check_new_pages(page, order));
--
2.30.2
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