linux-5.15/__alloc_pages() の履歴(No.1)

• 履歴一覧
• 差分 を表示
• 現在との差分 を表示
• ソース を表示
• linux-5.15/__alloc_pages() へ行く。
  • 1 (2025-10-24 (金) 12:42:27)

参照元†

説明†

• パス: [[linux-5.15/]]

• FIXME: これは何？
  • 説明

引数†

• gfp_t gfp
• unsigned int order
• int preferred_nid
• nodemask_t *nodemask
  • linux-5.15/nodemask_t

返り値†

• struct page *
  • linux-5.15/page

参考†

実装†

/*
 * This is the 'heart' of the zoned buddy allocator.
 */
struct page *__alloc_pages(gfp_t gfp, unsigned int order, int preferred_nid,
							nodemask_t *nodemask)
{
	struct page *page;
	unsigned int alloc_flags = ALLOC_WMARK_LOW;
	gfp_t alloc_gfp; /* The gfp_t that was actually used for allocation */
	struct alloc_context ac = { };

	/*
	 * There are several places where we assume that the order value is sane
	 * so bail out early if the request is out of bound.
	 */
	if (unlikely(order >= MAX_ORDER)) {
		WARN_ON_ONCE(!(gfp & __GFP_NOWARN));
		return NULL;
	}

• • linux-5.15/page
  • linux-5.15/gfp_t
  • linux-5.15/alloc_context
  • linux-5.15/unlikely()
  • linux-5.15/WARN_ON_ONCE()

	gfp &= gfp_allowed_mask;
	/*
	 * Apply scoped allocation constraints. This is mainly about GFP_NOFS
	 * resp. GFP_NOIO which has to be inherited for all allocation requests
	 * from a particular context which has been marked by
	 * memalloc_no{fs,io}_{save,restore}. And PF_MEMALLOC_PIN which ensures
	 * movable zones are not used during allocation.
	 */
	gfp = current_gfp_context(gfp);
	alloc_gfp = gfp;
	if (!prepare_alloc_pages(gfp, order, preferred_nid, nodemask, &ac,
			&alloc_gfp, &alloc_flags))
		return NULL;

• • linux-5.15/current_gfp_context()
  • linux-5.15/prepare_alloc_pages()

	/*
	 * Forbid the first pass from falling back to types that fragment
	 * memory until all local zones are considered.
	 */
	alloc_flags |= alloc_flags_nofragment(ac.preferred_zoneref->zone, gfp);

	/* First allocation attempt */
	page = get_page_from_freelist(alloc_gfp, order, alloc_flags, &ac);
	if (likely(page))
		goto out;

	alloc_gfp = gfp;
	ac.spread_dirty_pages = false;

• • linux-5.15/alloc_flags_nofragment()
  • linux-5.15/get_page_from_freelist()
  • linux-5.15/likely()

	/*
	 * Restore the original nodemask if it was potentially replaced with
	 * &cpuset_current_mems_allowed to optimize the fast-path attempt.
	 */
	ac.nodemask = nodemask;

	page = __alloc_pages_slowpath(alloc_gfp, order, &ac);

out:
	if (memcg_kmem_enabled() && (gfp & __GFP_ACCOUNT) && page &&
	    unlikely(__memcg_kmem_charge_page(page, gfp, order) != 0)) {
		__free_pages(page, order);
		page = NULL;
	}

• • linux-5.15/__alloc_pages_slowpath()
  • linux-5.15/memcg_kmem_enabled()
  • linux-5.15/unlikely()
  • linux-5.15/__memcg_kmem_charge_page()
  • linux-5.15/__free_pages()

	trace_mm_page_alloc(page, order, alloc_gfp, ac.migratetype);

	return page;
}
EXPORT_SYMBOL(__alloc_pages);

• • linux-5.15/trace_mm_page_alloc()
  • linux-5.15/EXPORT_SYMBOL()

コメント†