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Message-ID: <xa1t1udmsuoc.fsf@mina86.com>
Date: Tue, 15 Jan 2013 09:43:31 +0100
From: Michal Nazarewicz <mina86@...a86.com>
To: Minchan Kim <minchan@...nel.org>,
Andrew Morton <akpm@...ux-foundation.org>
Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org,
Minchan Kim <minchan@...nel.org>,
KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
Subject: Re: [PATCH v2] mm: remove MIGRATE_ISOLATE check in hotpath
On Tue, Jan 15 2013, Minchan Kim wrote:
> Now mm several functions test MIGRATE_ISOLATE and some of those
> are hotpath but MIGRATE_ISOLATE is used only if we enable
> CONFIG_MEMORY_ISOLATION(ie, CMA, memory-hotplug and memory-failure)
> which are not common config option. So let's not add unnecessary
> overhead and code when we don't enable CONFIG_MEMORY_ISOLATION.
>
> Cc: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
> Cc: Michal Nazarewicz <mina86@...a86.com>
Acked-by: Michal Nazarewicz <mina86@...a86.com>
> Signed-off-by: Minchan Kim <minchan@...nel.org>
> ---
> include/linux/mmzone.h | 2 ++
> include/linux/page-isolation.h | 19 +++++++++++++++++++
> mm/compaction.c | 6 +++++-
> mm/page_alloc.c | 16 ++++++++++------
> mm/vmstat.c | 2 ++
> 5 files changed, 38 insertions(+), 7 deletions(-)
>
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index 73b64a3..4f4c8c2 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -57,7 +57,9 @@ enum {
> */
> MIGRATE_CMA,
> #endif
> +#ifdef CONFIG_MEMORY_ISOLATION
> MIGRATE_ISOLATE, /* can't allocate from here */
> +#endif
> MIGRATE_TYPES
> };
>
> diff --git a/include/linux/page-isolation.h b/include/linux/page-isolation.h
> index a92061e..3fff8e7 100644
> --- a/include/linux/page-isolation.h
> +++ b/include/linux/page-isolation.h
> @@ -1,6 +1,25 @@
> #ifndef __LINUX_PAGEISOLATION_H
> #define __LINUX_PAGEISOLATION_H
>
> +#ifdef CONFIG_MEMORY_ISOLATION
> +static inline bool is_migrate_isolate_page(struct page *page)
> +{
> + return get_pageblock_migratetype(page) == MIGRATE_ISOLATE;
> +}
> +static inline bool is_migrate_isolate(int migratetype)
> +{
> + return migratetype == MIGRATE_ISOLATE;
> +}
> +#else
> +static inline bool is_migrate_isolate_page(struct page *page)
> +{
> + return false;
> +}
> +static inline bool is_migrate_isolate(int migratetype)
> +{
> + return false;
> +}
> +#endif
>
> bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
> bool skip_hwpoisoned_pages);
> diff --git a/mm/compaction.c b/mm/compaction.c
> index 675937c..bb2a655 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -15,6 +15,7 @@
> #include <linux/sysctl.h>
> #include <linux/sysfs.h>
> #include <linux/balloon_compaction.h>
> +#include <linux/page-isolation.h>
> #include "internal.h"
>
> #ifdef CONFIG_COMPACTION
> @@ -215,7 +216,10 @@ static bool suitable_migration_target(struct page *page)
> int migratetype = get_pageblock_migratetype(page);
>
> /* Don't interfere with memory hot-remove or the min_free_kbytes blocks */
> - if (migratetype == MIGRATE_ISOLATE || migratetype == MIGRATE_RESERVE)
> + if (migratetype == MIGRATE_RESERVE)
> + return false;
> +
> + if (is_migrate_isolate(migratetype))
> return false;
>
> /* If the page is a large free page, then allow migration */
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 82117f5..319a8f0 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -665,7 +665,7 @@ static void free_pcppages_bulk(struct zone *zone, int count,
> /* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */
> __free_one_page(page, zone, 0, mt);
> trace_mm_page_pcpu_drain(page, 0, mt);
> - if (likely(get_pageblock_migratetype(page) != MIGRATE_ISOLATE)) {
> + if (likely(!is_migrate_isolate_page(page))) {
> __mod_zone_page_state(zone, NR_FREE_PAGES, 1);
> if (is_migrate_cma(mt))
> __mod_zone_page_state(zone, NR_FREE_CMA_PAGES, 1);
> @@ -683,7 +683,7 @@ static void free_one_page(struct zone *zone, struct page *page, int order,
> zone->pages_scanned = 0;
>
> __free_one_page(page, zone, order, migratetype);
> - if (unlikely(migratetype != MIGRATE_ISOLATE))
> + if (unlikely(!is_migrate_isolate(migratetype)))
> __mod_zone_freepage_state(zone, 1 << order, migratetype);
> spin_unlock(&zone->lock);
> }
> @@ -911,7 +911,9 @@ static int fallbacks[MIGRATE_TYPES][4] = {
> [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_RESERVE },
> #endif
> [MIGRATE_RESERVE] = { MIGRATE_RESERVE }, /* Never used */
> +#ifdef CONFIG_MEMORY_ISOLATION
> [MIGRATE_ISOLATE] = { MIGRATE_RESERVE }, /* Never used */
> +#endif
> };
>
> /*
> @@ -1137,7 +1139,7 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order,
> list_add_tail(&page->lru, list);
> if (IS_ENABLED(CONFIG_CMA)) {
> mt = get_pageblock_migratetype(page);
> - if (!is_migrate_cma(mt) && mt != MIGRATE_ISOLATE)
> + if (!is_migrate_cma(mt) && !is_migrate_isolate(mt))
> mt = migratetype;
> }
> set_freepage_migratetype(page, mt);
> @@ -1321,7 +1323,7 @@ void free_hot_cold_page(struct page *page, int cold)
> * excessively into the page allocator
> */
> if (migratetype >= MIGRATE_PCPTYPES) {
> - if (unlikely(migratetype == MIGRATE_ISOLATE)) {
> + if (unlikely(is_migrate_isolate(migratetype))) {
> free_one_page(zone, page, 0, migratetype);
> goto out;
> }
> @@ -1402,7 +1404,7 @@ int capture_free_page(struct page *page, int alloc_order, int migratetype)
> order = page_order(page);
> mt = get_pageblock_migratetype(page);
>
> - if (mt != MIGRATE_ISOLATE) {
> + if (!is_migrate_isolate(mt)) {
> /* Obey watermarks as if the page was being allocated */
> watermark = low_wmark_pages(zone) + (1 << order);
> if (!zone_watermark_ok(zone, 0, watermark, 0, 0))
> @@ -1425,7 +1427,7 @@ int capture_free_page(struct page *page, int alloc_order, int migratetype)
> struct page *endpage = page + (1 << order) - 1;
> for (; page < endpage; page += pageblock_nr_pages) {
> int mt = get_pageblock_migratetype(page);
> - if (mt != MIGRATE_ISOLATE && !is_migrate_cma(mt))
> + if (!is_migrate_isolate(mt) && !is_migrate_cma(mt))
> set_pageblock_migratetype(page,
> MIGRATE_MOVABLE);
> }
> @@ -2911,7 +2913,9 @@ static void show_migration_types(unsigned char type)
> #ifdef CONFIG_CMA
> [MIGRATE_CMA] = 'C',
> #endif
> +#ifdef CONFIG_MEMORY_ISOLATION
> [MIGRATE_ISOLATE] = 'I',
> +#endif
> };
> char tmp[MIGRATE_TYPES + 1];
> char *p = tmp;
> diff --git a/mm/vmstat.c b/mm/vmstat.c
> index 7a65e26..b0f1db1 100644
> --- a/mm/vmstat.c
> +++ b/mm/vmstat.c
> @@ -628,7 +628,9 @@ static char * const migratetype_names[MIGRATE_TYPES] = {
> #ifdef CONFIG_CMA
> "CMA",
> #endif
> +#ifdef CONFIG_MEMORY_ISOLATION
> "Isolate",
> +#endif
> };
>
> static void *frag_start(struct seq_file *m, loff_t *pos)
--
Best regards, _ _
.o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o
..o | Computer Science, Michał “mina86” Nazarewicz (o o)
ooo +----<email/xmpp: mpn@...gle.com>--------------ooO--(_)--Ooo--
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