should_reclaim_retry

Name:Checks whether it makes sense to retry the reclaim to make a forward progress* for the given allocation request.* We give up when we either have tried MAX_RECLAIM_RETRIES in a row* without success, or when we couldn't even meet the watermark if we

Proto:static inline bool should_reclaim_retry(gfp_t gfp_mask, unsigned order, struct alloc_context *ac, int alloc_flags, bool did_some_progress, int *no_progress_loops)

Type:bool

Parameter:

Type	Parameter	Name
gfp_t	gfp_mask
unsigned	order
struct alloc_context *	ac
int	alloc_flags
bool	did_some_progress
int *	no_progress_loops

4272

bool ret = false

4279

If did_some_progress && order <= PAGE_ALLOC_COSTLY_ORDER is the order at which allocations are deemed* costly to service. That is between allocation orders which should* coalesce naturally under reasonable reclaim pressure and those which* will not. Then no_progress_loops = 0

4281

Else no_progress_loops++

4288

If no_progress_loops > Maximum number of reclaim retries without progress before the OOM* killer is consider the only way forward. Then

4290

Return Used when an allocation is about to fail under memory pressure

4303

min_wmark = min_wmark_pages(zone)

4306

available = reclaimable = This misses isolated pages which are not accounted for to save counters.* As the data only determines if reclaim or compaction continues, it is* not expected that isolated pages will be a dominating factor.

4307

available += More accurate version that also considers the currently pending* deltas. For that we need to loop over all cpus to find the current* deltas. There is no synchronization so the result cannot be* exactly accurate either.

4313

wmark = Return true if free base pages are above 'mark'. For high-order checks it* will return true of the order-0 watermark is reached and there is at least* one free page of a suitable size. Checking now avoids taking the zone lock

4315

trace_reclaim_retry_zone(z, order, reclaimable, available, min_wmark, * no_progress_loops, wmark)

4317

If wmark Then

4324

If Not did_some_progress Then

4327

write_pending = More accurate version that also considers the currently pending* deltas. For that we need to loop over all cpus to find the current* deltas. There is no synchronization so the result cannot be* exactly accurate either.

4330

If 2 * write_pending > reclaimable Then

4331

gestion_wait - wait for a backing_dev to become uncongested*@sync: SYNC or ASYNC IO*@timeout: timeout in jiffies* Waits for up to @timeout jiffies for a backing_dev (any backing_dev) to exit* write congestion

4332

Return true

4336

ret = true

4337

Go to out

4341

out :

4349

If flags & I'm a workqueue worker Then schedule_timeout_uninterruptible(1)

4351

Else cond_resched()

4353

Return ret

**Caller**
Name	Describe
__alloc_pages_slowpath

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