From: Mel Gorman <mgorman@techsingularity.net>
To: Minchan Kim <minchan@kernel.org>
Cc: Nicolas Saenz Julienne <nsaenzju@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
Vlastimil Babka <vbabka@suse.cz>,
Michal Hocko <mhocko@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>
Subject: Re: [PATCH 5/6] mm/page_alloc: Protect PCP lists with a spinlock
Date: Fri, 29 Apr 2022 10:05:11 +0100 [thread overview]
Message-ID: <20220429090511.GA3441@techsingularity.net> (raw)
In-Reply-To: <YmhHCHaUy+zARWxi@google.com>
On Tue, Apr 26, 2022 at 12:24:56PM -0700, Minchan Kim wrote:
> > @@ -3450,10 +3496,19 @@ void free_unref_page(struct page *page, unsigned int order)
> > void free_unref_page_list(struct list_head *list)
> > {
> > struct page *page, *next;
> > + struct per_cpu_pages *pcp;
> > + struct zone *locked_zone;
> > unsigned long flags;
> > int batch_count = 0;
> > int migratetype;
> >
> > + /*
> > + * An empty list is possible. Check early so that the later
> > + * lru_to_page() does not potentially read garbage.
> > + */
> > + if (list_empty(list))
> > + return;
> > +
> > /* Prepare pages for freeing */
> > list_for_each_entry_safe(page, next, list, lru) {
> > unsigned long pfn = page_to_pfn(page);
> > @@ -3474,8 +3529,26 @@ void free_unref_page_list(struct list_head *list)
> > }
> > }
> >
> > + VM_BUG_ON(in_hardirq());
>
> You need to check the list_empty here again and bail out if it is.
>
You're right, every page could have failed to prepare or was isolated.
--
Mel Gorman
SUSE Labs
next prev parent reply other threads:[~2022-04-29 9:05 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-20 9:59 [RFC PATCH 0/6] Drain remote per-cpu directly Mel Gorman
2022-04-20 9:59 ` [PATCH 1/6] mm/page_alloc: Add page->buddy_list and page->pcp_list Mel Gorman
2022-04-20 20:43 ` Matthew Wilcox
2022-04-21 8:38 ` Mel Gorman
2022-04-20 9:59 ` [PATCH 2/6] mm/page_alloc: Use only one PCP list for THP-sized allocations Mel Gorman
2022-04-20 9:59 ` [PATCH 3/6] mm/page_alloc: Split out buddy removal code from rmqueue into separate helper Mel Gorman
2022-04-20 9:59 ` [PATCH 4/6] mm/page_alloc: Remove unnecessary page == NULL check in rmqueue Mel Gorman
2022-04-20 9:59 ` [PATCH 5/6] mm/page_alloc: Protect PCP lists with a spinlock Mel Gorman
2022-04-26 16:42 ` Nicolas Saenz Julienne
2022-04-26 16:48 ` Vlastimil Babka
2022-04-29 9:13 ` Mel Gorman
2022-04-26 19:24 ` Minchan Kim
2022-04-29 9:05 ` Mel Gorman [this message]
2022-04-20 9:59 ` [PATCH 6/6] mm/page_alloc: Remotely drain per-cpu lists Mel Gorman
[not found] ` <20220420140214.2330-1-hdanton@sina.com>
2022-04-20 14:35 ` [PATCH 5/6] mm/page_alloc: Protect PCP lists with a spinlock Nicolas Saenz Julienne
2022-04-25 22:58 ` [RFC PATCH 0/6] Drain remote per-cpu directly Minchan Kim
2022-04-26 11:06 ` Nicolas Saenz Julienne
2022-04-27 15:21 ` Marcelo Tosatti
2022-04-26 2:49 ` Suren Baghdasaryan
2022-04-26 6:30 ` Suren Baghdasaryan
2022-05-09 13:07 [RFC PATCH 0/6] Drain remote per-cpu directly v2 Mel Gorman
2022-05-09 13:08 ` [PATCH 5/6] mm/page_alloc: Protect PCP lists with a spinlock Mel Gorman
2022-05-22 2:49 ` Hugh Dickins
2022-05-24 12:12 ` Mel Gorman
2022-05-24 12:19 ` Mel Gorman
2022-05-12 8:50 [PATCH 0/6] Drain remote per-cpu directly v3 Mel Gorman
2022-05-12 8:50 ` [PATCH 5/6] mm/page_alloc: Protect PCP lists with a spinlock Mel Gorman
2022-05-13 12:22 ` Nicolas Saenz Julienne
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