linux-5.15/rmqueue() の変更点

• 追加された行はこの色です。
• 削除された行はこの色です。
• linux-5.15/rmqueue() へ行く。
• linux-5.15/rmqueue() の差分を削除

#author("2025-09-13T01:23:44+09:00","default:guest","guest")
#author("2025-09-13T01:28:45+09:00","default:guest","guest")
*参照元 [#y99b61f7]
#backlinks

*説明 [#cd36dd34]
-パス: [[linux-5.15/mm/page_alloc.c]]

-FIXME: これは何？
--説明


**引数 [#u34e2f23]
-struct zone *preferred_zone
--
--[[linux-5.15/zone]]
-struct zone *zone
--
--[[linux-5.15/zone]]
-unsigned int order
--
-gfp_t gfp_flags
--
--[[linux-5.15/gfp_t]]
-unsigned int alloc_flags
--
-int migratetype
--


**返り値 [#oecaaeca]
-struct page *
--
--[[linux-5.15/page]]


**参考 [#o5c9f81d]


*実装 [#c2edd239]

 /*
  * Allocate a page from the given zone. Use pcplists for order-0 allocations.
  */
 static inline
 struct page *rmqueue(struct zone *preferred_zone,
 			struct zone *zone, unsigned int order,
 			gfp_t gfp_flags, unsigned int alloc_flags,
 			int migratetype)
 {
 	unsigned long flags;
 	struct page *page;
 
 	if (likely(pcp_allowed_order(order))) {
 		/*
 		 * MIGRATE_MOVABLE pcplist could have the pages on CMA area and
 		 * we need to skip it when CMA area isn't allowed.
 		 */
 		if (!IS_ENABLED(CONFIG_CMA) || alloc_flags & ALLOC_CMA ||
 				migratetype != MIGRATE_MOVABLE) {
 			page = rmqueue_pcplist(preferred_zone, zone, order,
 					gfp_flags, migratetype, alloc_flags);
 			goto out;
 		}
 	}
 
-
--[[linux-5.15/page]]
--[[linux-5.15/likely()]]
--[[linux-5.15/pcp_allowed_order()]]
--[[linux-5.15/IS_ENABLED()]]
--[[linux-5.15/rmqueue_pcplist()]]

 	/*
 	 * We most definitely don't want callers attempting to
 	 * allocate greater than order-1 page units with __GFP_NOFAIL.
 	 */
 	WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1));
 	spin_lock_irqsave(&zone->lock, flags);
 
-
--[[linux-5.15/WARN_ON_ONCE()]]
--[[linux-5.15/spin_lock_irqsave()]]

 	do {
 		page = NULL;
 		/*
 		 * order-0 request can reach here when the pcplist is skipped
 		 * due to non-CMA allocation context. HIGHATOMIC area is
 		 * reserved for high-order atomic allocation, so order-0
 		 * request should skip it.
 		 */
 		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);
 	} while (page && check_new_pages(page, order));
 	if (!page)
 		goto failed;
 
-
--[[linux-5.15/__rmqueue_smallest()]]
--[[linux-5.15/trace_mm_page_alloc_zone_locked()]]
--[[linux-5.15/__rmqueue()]]
--[[linux-5.15/check_new_pages()]]

 	__mod_zone_freepage_state(zone, -(1 << order),
 				  get_pcppage_migratetype(page));
 	spin_unlock_irqrestore(&zone->lock, flags);
 
 	__count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order);
 	zone_statistics(preferred_zone, zone, 1);
 
-
--[[linux-5.15/__mm_zone_freepage_state()]]
--[[linux-5.15/get_pcppage_migratetype()]]
--[[linux-5.15/spin_unlock_irqrestore()]]
--[[linux-5.15/__count_zid_vm_events()]]
--[[linux-5.15/page_zonenum()]]
--[[linux-5.15/zone_statistics()]]

 out:
 	/* Separate test+clear to avoid unnecessary atomics */
 	if (test_bit(ZONE_BOOSTED_WATERMARK, &zone->flags)) {
 		clear_bit(ZONE_BOOSTED_WATERMARK, &zone->flags);
 		wakeup_kswapd(zone, 0, 0, zone_idx(zone));
 	}
 
 	VM_BUG_ON_PAGE(page && bad_range(zone, page), page);
 	return page;
 
-
-ゾーンのwatermark boostが設定されていたら、kswapdを起こしてページ回収する。
-ZONE_BOOSTED_WATERMARKを設定する箇所は、今のところsteal_suitable_fallback()関数のみ。
--[[linux-5.15/test_bit()]]
--[[linux-5.15/clear_bit()]]
--[[linux-5.15/wakeup_kswapd()]]
--[[linux-5.15/zone_idx()]]
--[[linux-5.15/VM_BUG_ON_PAGE()]]
--[[linux-5.15/bad_range()]]
--[[linux-5.15/steal_suitable_fallback()]]

 failed:
 	spin_unlock_irqrestore(&zone->lock, flags);
 	return NULL;
 }

-
--[[linux-5.15/spin_unlock_irqrestore()]]


*コメント [#tdf69a16]