From: Mel Gorman <mgorman@techsingularity.net>
To: Linux-MM <linux-mm@kvack.org>,
Linux-RT-Users <linux-rt-users@vger.kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Chuck Lever <chuck.lever@oracle.com>,
Jesper Dangaard Brouer <brouer@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>, Michal Hocko <mhocko@kernel.org>,
Vlastimil Babka <vbabka@suse.cz>,
Mel Gorman <mgorman@techsingularity.net>
Subject: [PATCH 08/11] mm/page_alloc: Explicitly acquire the zone lock in __free_pages_ok
Date: Wed, 14 Apr 2021 14:39:28 +0100 [thread overview]
Message-ID: <20210414133931.4555-9-mgorman@techsingularity.net> (raw)
In-Reply-To: <20210414133931.4555-1-mgorman@techsingularity.net>
__free_pages_ok() disables IRQs before calling a common helper
free_one_page() that acquires the zone lock. This is not safe according
to Documentation/locking/locktypes.rst and in this context, IRQ disabling
is not protecting a per_cpu_pages structure either or a local_lock would
be used.
This patch explicitly acquires the lock with spin_lock_irqsave instead of
relying on a helper. This removes the last instance of local_irq_save()
in page_alloc.c.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
---
mm/page_alloc.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 1ed370668e7f..6791e9361076 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1559,21 +1559,18 @@ static void __free_pages_ok(struct page *page, unsigned int order,
unsigned long flags;
int migratetype;
unsigned long pfn = page_to_pfn(page);
+ struct zone *zone = page_zone(page);
if (!free_pages_prepare(page, order, true))
return;
migratetype = get_pfnblock_migratetype(page, pfn);
- /*
- * TODO FIX: Disable IRQs before acquiring IRQ-safe zone->lock
- * and protect vmstat updates.
- */
- local_irq_save(flags);
+ spin_lock_irqsave(&zone->lock, flags);
__count_vm_events(PGFREE, 1 << order);
- free_one_page(page_zone(page), page, pfn, order, migratetype,
- fpi_flags);
- local_irq_restore(flags);
+ migratetype = check_migratetype_isolated(zone, page, pfn, migratetype);
+ __free_one_page(page, pfn, zone, order, migratetype, fpi_flags);
+ spin_unlock_irqrestore(&zone->lock, flags);
}
void __free_pages_core(struct page *page, unsigned int order)
--
2.26.2
next prev parent reply other threads:[~2021-04-14 13:41 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-14 13:39 [PATCH 0/11 v3] Use local_lock for pcp protection and reduce stat overhead Mel Gorman
2021-04-14 13:39 ` [PATCH 01/11] mm/page_alloc: Split per cpu page lists and zone stats Mel Gorman
2021-04-14 13:39 ` [PATCH 02/11] mm/page_alloc: Convert per-cpu list protection to local_lock Mel Gorman
2021-04-14 13:39 ` [PATCH 03/11] mm/vmstat: Convert NUMA statistics to basic NUMA counters Mel Gorman
2021-04-14 13:39 ` [PATCH 04/11] mm/vmstat: Inline NUMA event counter updates Mel Gorman
2021-04-14 16:20 ` Vlastimil Babka
2021-04-14 16:26 ` Vlastimil Babka
2021-04-15 9:34 ` Mel Gorman
2021-04-14 13:39 ` [PATCH 05/11] mm/page_alloc: Batch the accounting updates in the bulk allocator Mel Gorman
2021-04-14 16:31 ` Vlastimil Babka
2021-04-14 13:39 ` [PATCH 06/11] mm/page_alloc: Reduce duration that IRQs are disabled for VM counters Mel Gorman
2021-04-14 17:10 ` Vlastimil Babka
2021-04-14 13:39 ` [PATCH 07/11] mm/page_alloc: Remove duplicate checks if migratetype should be isolated Mel Gorman
2021-04-14 17:21 ` Vlastimil Babka
2021-04-15 9:33 ` Mel Gorman
2021-04-15 11:24 ` Vlastimil Babka
2021-04-14 13:39 ` Mel Gorman [this message]
2021-04-15 10:24 ` [PATCH 08/11] mm/page_alloc: Explicitly acquire the zone lock in __free_pages_ok Vlastimil Babka
2021-04-14 13:39 ` [PATCH 09/11] mm/page_alloc: Avoid conflating IRQs disabled with zone->lock Mel Gorman
2021-04-15 12:25 ` Vlastimil Babka
2021-04-15 14:11 ` Mel Gorman
2021-04-14 13:39 ` [PATCH 10/11] mm/page_alloc: Update PGFREE outside the zone lock in __free_pages_ok Mel Gorman
2021-04-15 13:04 ` Vlastimil Babka
2021-04-14 13:39 ` [PATCH 11/11] mm/page_alloc: Embed per_cpu_pages locking within the per-cpu structure Mel Gorman
2021-04-15 14:53 ` Vlastimil Babka
2021-04-15 15:29 ` Mel Gorman
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