extern void compaction_defer_reset(struct zone *zone, int order,
bool alloc_success);
-/* Compaction has made some progress and retrying makes sense */
-static inline bool compaction_made_progress(enum compact_result result)
-{
- /*
- * Even though this might sound confusing this in fact tells us
- * that the compaction successfully isolated and migrated some
- * pageblocks.
- */
- if (result == COMPACT_SUCCESS)
- return true;
-
- return false;
-}
-
-/* Compaction has failed and it doesn't make much sense to keep retrying. */
-static inline bool compaction_failed(enum compact_result result)
-{
- /* All zones were scanned completely and still not result. */
- if (result == COMPACT_COMPLETE)
- return true;
-
- return false;
-}
-
-/* Compaction needs reclaim to be performed first, so it can continue. */
-static inline bool compaction_needs_reclaim(enum compact_result result)
-{
- /*
- * Compaction backed off due to watermark checks for order-0
- * so the regular reclaim has to try harder and reclaim something.
- */
- if (result == COMPACT_SKIPPED)
- return true;
-
- return false;
-}
-
-/*
- * Compaction has backed off for some reason after doing some work or none
- * at all. It might be throttling or lock contention. Retrying might be still
- * worthwhile, but with a higher priority if allowed.
- */
-static inline bool compaction_withdrawn(enum compact_result result)
-{
- /*
- * If compaction is deferred for high-order allocations, it is
- * because sync compaction recently failed. If this is the case
- * and the caller requested a THP allocation, we do not want
- * to heavily disrupt the system, so we fail the allocation
- * instead of entering direct reclaim.
- */
- if (result == COMPACT_DEFERRED)
- return true;
-
- /*
- * If compaction in async mode encounters contention or blocks higher
- * priority task we back off early rather than cause stalls.
- */
- if (result == COMPACT_CONTENDED)
- return true;
-
- /*
- * Page scanners have met but we haven't scanned full zones so this
- * is a back off in fact.
- */
- if (result == COMPACT_PARTIAL_SKIPPED)
- return true;
-
- return false;
-}
-
-
bool compaction_zonelist_suitable(struct alloc_context *ac, int order,
int alloc_flags);
return COMPACT_SKIPPED;
}
-static inline bool compaction_made_progress(enum compact_result result)
-{
- return false;
-}
-
-static inline bool compaction_failed(enum compact_result result)
-{
- return false;
-}
-
-static inline bool compaction_needs_reclaim(enum compact_result result)
-{
- return false;
-}
-
-static inline bool compaction_withdrawn(enum compact_result result)
-{
- return true;
-}
-
static inline void kcompactd_run(int nid)
{
}
if (fatal_signal_pending(current))
return false;
- if (compaction_made_progress(compact_result))
+ /*
+ * Compaction managed to coalesce some page blocks, but the
+ * allocation failed presumably due to a race. Retry some.
+ */
+ if (compact_result == COMPACT_SUCCESS)
(*compaction_retries)++;
/*
- * compaction considers all the zone as desperately out of memory
- * so it doesn't really make much sense to retry except when the
+ * All zones were scanned completely and still no result. It
+ * doesn't really make much sense to retry except when the
* failure could be caused by insufficient priority
*/
- if (compaction_failed(compact_result))
+ if (compact_result == COMPACT_COMPLETE)
goto check_priority;
/*
- * compaction was skipped because there are not enough order-0 pages
- * to work with, so we retry only if it looks like reclaim can help.
+ * Compaction was skipped due to a lack of free order-0
+ * migration targets. Continue if reclaim can help.
*/
- if (compaction_needs_reclaim(compact_result)) {
+ if (compact_result == COMPACT_SKIPPED) {
ret = compaction_zonelist_suitable(ac, order, alloc_flags);
goto out;
}
/*
- * make sure the compaction wasn't deferred or didn't bail out early
- * due to locks contention before we declare that we should give up.
- * But the next retry should use a higher priority if allowed, so
- * we don't just keep bailing out endlessly.
+ * If compaction backed due to being deferred, due to
+ * contended locks in async mode, or due to scanners meeting
+ * after a partial scan, retry with increased priority.
*/
- if (compaction_withdrawn(compact_result)) {
+ if (compact_result == COMPACT_DEFERRED ||
+ compact_result == COMPACT_CONTENDED ||
+ compact_result == COMPACT_PARTIAL_SKIPPED)
goto check_priority;
- }
/*
* !costly requests are much more important than __GFP_RETRY_MAYFAIL