From: Vlastimil Babka <vbabka@suse.cz>
To: David Hildenbrand <david@redhat.com>, linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org, linux-hyperv@vger.kernel.org,
xen-devel@lists.xenproject.org, linux-acpi@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Alexander Duyck <alexander.h.duyck@linux.intel.com>,
Mel Gorman <mgorman@techsingularity.net>,
Michal Hocko <mhocko@kernel.org>,
Dave Hansen <dave.hansen@intel.com>,
Wei Yang <richard.weiyang@linux.alibaba.com>,
Oscar Salvador <osalvador@suse.de>,
Mike Rapoport <rppt@kernel.org>,
"K. Y. Srinivasan" <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
Wei Liu <wei.liu@kernel.org>
Subject: Re: [PATCH RFC 4/4] mm/page_alloc: place pages to tail in __free_pages_core()
Date: Thu, 24 Sep 2020 15:44:52 +0200 [thread overview]
Message-ID: <34a094bd-d37a-b735-14bb-ea65e2e2b7a1@suse.cz> (raw)
In-Reply-To: <20200916183411.64756-5-david@redhat.com>
On 9/16/20 8:34 PM, David Hildenbrand wrote:
> __free_pages_core() is used when exposing fresh memory to the buddy
> during system boot and when onlining memory in generic_online_page().
>
> generic_online_page() is used in two cases:
>
> 1. Direct memory onlining in online_pages().
> 2. Deferred memory onlining in memory-ballooning-like mechanisms (HyperV
> balloon and virtio-mem), when parts of a section are kept
> fake-offline to be fake-onlined later on.
>
> In 1, we already place pages to the tail of the freelist. Pages will be
> freed to MIGRATE_ISOLATE lists first and moved to the tail of the freelists
> via undo_isolate_page_range().
>
> In 2, we currently don't implement a proper rule. In case of virtio-mem,
> where we currently always online MAX_ORDER - 1 pages, the pages will be
> placed to the HEAD of the freelist - undesireable. While the hyper-v
> balloon calls generic_online_page() with single pages, usually it will
> call it on successive single pages in a larger block.
>
> The pages are fresh, so place them to the tail of the freelists and avoid
> the PCP.
>
> Note: If we detect that the new behavior is undesireable for
> __free_pages_core() during boot, we can let the caller specify the
> behavior.
>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
> Cc: Mel Gorman <mgorman@techsingularity.net>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Dave Hansen <dave.hansen@intel.com>
> Cc: Vlastimil Babka <vbabka@suse.cz>
> Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
> Cc: Oscar Salvador <osalvador@suse.de>
> Cc: Mike Rapoport <rppt@kernel.org>
> Cc: "K. Y. Srinivasan" <kys@microsoft.com>
> Cc: Haiyang Zhang <haiyangz@microsoft.com>
> Cc: Stephen Hemminger <sthemmin@microsoft.com>
> Cc: Wei Liu <wei.liu@kernel.org>
> Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
> ---
> mm/page_alloc.c | 32 ++++++++++++++++++++------------
> 1 file changed, 20 insertions(+), 12 deletions(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 75b0f49b4022..50746e6dc21b 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -264,7 +264,8 @@ bool pm_suspended_storage(void)
> unsigned int pageblock_order __read_mostly;
> #endif
>
> -static void __free_pages_ok(struct page *page, unsigned int order);
> +static void __free_pages_ok(struct page *page, unsigned int order,
> + fop_t fop_flags);
>
> /*
> * results with 256, 32 in the lowmem_reserve sysctl:
> @@ -676,7 +677,7 @@ static void bad_page(struct page *page, const char *reason)
> void free_compound_page(struct page *page)
> {
> mem_cgroup_uncharge(page);
> - __free_pages_ok(page, compound_order(page));
> + __free_pages_ok(page, compound_order(page), FOP_NONE);
> }
>
> void prep_compound_page(struct page *page, unsigned int order)
> @@ -1402,17 +1403,15 @@ static void free_pcppages_bulk(struct zone *zone, int count,
> spin_unlock(&zone->lock);
> }
>
> -static void free_one_page(struct zone *zone,
> - struct page *page, unsigned long pfn,
> - unsigned int order,
> - int migratetype)
> +static void free_one_page(struct zone *zone, struct page *page, unsigned long pfn,
> + unsigned int order, int migratetype, fop_t fop_flags)
> {
> spin_lock(&zone->lock);
> if (unlikely(has_isolate_pageblock(zone) ||
> is_migrate_isolate(migratetype))) {
> migratetype = get_pfnblock_migratetype(page, pfn);
> }
> - __free_one_page(page, pfn, zone, order, migratetype, FOP_NONE);
> + __free_one_page(page, pfn, zone, order, migratetype, fop_flags);
> spin_unlock(&zone->lock);
> }
>
> @@ -1490,7 +1489,8 @@ void __meminit reserve_bootmem_region(phys_addr_t start, phys_addr_t end)
> }
> }
>
> -static void __free_pages_ok(struct page *page, unsigned int order)
> +static void __free_pages_ok(struct page *page, unsigned int order,
> + fop_t fop_flags)
> {
> unsigned long flags;
> int migratetype;
> @@ -1502,7 +1502,8 @@ static void __free_pages_ok(struct page *page, unsigned int order)
> migratetype = get_pfnblock_migratetype(page, pfn);
> local_irq_save(flags);
> __count_vm_events(PGFREE, 1 << order);
> - free_one_page(page_zone(page), page, pfn, order, migratetype);
> + free_one_page(page_zone(page), page, pfn, order, migratetype,
> + fop_flags);
> local_irq_restore(flags);
> }
>
> @@ -1523,7 +1524,13 @@ void __free_pages_core(struct page *page, unsigned int order)
>
> atomic_long_add(nr_pages, &page_zone(page)->managed_pages);
> set_page_refcounted(page);
> - __free_pages(page, order);
> +
> + /*
> + * Bypass PCP and place fresh pages right to the tail, primarily
> + * relevant for memory onlining.
> + */
> + page_ref_dec(page);
> + __free_pages_ok(page, order, FOP_TO_TAIL);
> }
>
> #ifdef CONFIG_NEED_MULTIPLE_NODES
> @@ -3167,7 +3174,8 @@ static void free_unref_page_commit(struct page *page, unsigned long pfn)
> */
> if (migratetype >= MIGRATE_PCPTYPES) {
> if (unlikely(is_migrate_isolate(migratetype))) {
> - free_one_page(zone, page, pfn, 0, migratetype);
> + free_one_page(zone, page, pfn, 0, migratetype,
> + FOP_NONE);
> return;
> }
> migratetype = MIGRATE_MOVABLE;
> @@ -4984,7 +4992,7 @@ static inline void free_the_page(struct page *page, unsigned int order)
> if (order == 0) /* Via pcp? */
> free_unref_page(page);
> else
> - __free_pages_ok(page, order);
> + __free_pages_ok(page, order, FOP_NONE);
> }
>
> void __free_pages(struct page *page, unsigned int order)
>
next prev parent reply other threads:[~2020-09-24 13:44 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-16 18:34 [PATCH RFC 0/4] mm: place pages to the freelist tail when onling and undoing isolation David Hildenbrand
2020-09-16 18:34 ` [PATCH RFC 1/4] mm/page_alloc: convert "report" flag of __free_one_page() to a proper flag David Hildenbrand
2020-09-16 21:44 ` Alexander Duyck
2020-09-18 1:53 ` Wei Yang
2020-09-18 7:23 ` David Hildenbrand
2020-09-24 10:19 ` Vlastimil Babka
2020-09-25 10:34 ` Oscar Salvador
2020-09-16 18:34 ` [PATCH RFC 2/4] mm/page_alloc: place pages to tail in __putback_isolated_page() David Hildenbrand
2020-09-16 21:50 ` Alexander Duyck
2020-09-18 2:07 ` Wei Yang
2020-09-18 7:27 ` David Hildenbrand
2020-09-21 1:57 ` Wei Yang
2020-09-18 2:16 ` Wei Yang
2020-09-18 7:29 ` David Hildenbrand
2020-09-24 10:37 ` Vlastimil Babka
2020-09-25 8:10 ` David Hildenbrand
2020-09-25 13:19 ` Oscar Salvador
2020-09-25 13:30 ` David Hildenbrand
2020-09-16 18:34 ` [PATCH RFC 3/4] mm/page_alloc: always move pages to the tail of the freelist in unset_migratetype_isolate() David Hildenbrand
2020-09-18 2:29 ` Wei Yang
2020-09-18 7:30 ` David Hildenbrand
2020-09-24 11:13 ` Vlastimil Babka
2020-09-25 2:45 ` Wei Yang
2020-09-25 8:05 ` David Hildenbrand
2020-09-25 8:39 ` Vlastimil Babka
2020-09-25 13:13 ` David Hildenbrand
2020-09-25 13:57 ` Oscar Salvador
2020-09-16 18:34 ` [PATCH RFC 4/4] mm/page_alloc: place pages to tail in __free_pages_core() David Hildenbrand
2020-09-24 13:44 ` Vlastimil Babka [this message]
2020-09-28 7:58 ` Oscar Salvador
2020-09-28 8:36 ` David Hildenbrand
2020-09-28 12:53 ` Oscar Salvador
2020-09-16 18:50 ` [PATCH RFC 0/4] mm: place pages to the freelist tail when onling and undoing isolation osalvador
2020-09-16 19:31 ` David Hildenbrand
2020-09-18 2:30 ` Wei Yang
2020-09-18 7:32 ` David Hildenbrand
2020-09-23 14:31 ` Vlastimil Babka
2020-09-23 15:26 ` David Hildenbrand
2020-09-24 9:40 ` Mel Gorman
2020-09-24 9:54 ` David Hildenbrand
2020-09-24 13:59 ` Vlastimil Babka
2020-09-24 14:29 ` David Hildenbrand
2020-09-24 1:57 ` Wei Yang
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