linux-5.15/prepare_alloc_pages()

参照元†

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説明†

パス: linux-5.15/mm/page_alloc.c

FIXME: これは何？
- 説明

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引数†

gfp_t gfp_mask
- linux-5.15/gfp_t
unsigned int order
int preferred_nid
nodemask_t *nodemask
- linux-5.15/nodemask_t
struct alloc_context *ac
- linux-5.15/alloc_context
gfp_t *alloc_gfp
- linux-5.15/gfp_t
unsigned int *alloc_flags

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返り値†

bool

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参考†

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実装†

static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order,
		int preferred_nid, nodemask_t *nodemask,
		struct alloc_context *ac, gfp_t *alloc_gfp,
		unsigned int *alloc_flags)
{
	ac->highest_zoneidx = gfp_zone(gfp_mask);
	ac->zonelist = node_zonelist(preferred_nid, gfp_mask);
	ac->nodemask = nodemask;
	ac->migratetype = gfp_migratetype(gfp_mask);

	if (cpusets_enabled()) {
		*alloc_gfp |= __GFP_HARDWALL;
		/*
		 * When we are in the interrupt context, it is irrelevant
		 * to the current task context. It means that any node ok.
		 */
		if (in_task() && !ac->nodemask)
			ac->nodemask = &cpuset_current_mems_allowed;
		else
			*alloc_flags |= ALLOC_CPUSET;
	}

	fs_reclaim_acquire(gfp_mask);
	fs_reclaim_release(gfp_mask);

	might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM);

	if (should_fail_alloc_page(gfp_mask, order))
		return false;

	*alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, *alloc_flags);

	/* Dirty zone balancing only done in the fast path */
	ac->spread_dirty_pages = (gfp_mask & __GFP_WRITE);

	/*
	 * The preferred zone is used for statistics but crucially it is
	 * also used as the starting point for the zonelist iterator. It
	 * may get reset for allocations that ignore memory policies.
	 */
	ac->preferred_zoneref = first_zones_zonelist(ac->zonelist,
					ac->highest_zoneidx, ac->nodemask);

	return true;
}