*
* Isolate all pages that can be migrated from the range specified by
* [low_pfn, end_pfn). The range is expected to be within same pageblock.
- * Returns zero if there is a fatal signal pending, otherwise PFN of the
- * first page that was not scanned (which may be both less, equal to or more
- * than end_pfn).
+ * Returns errno, like -EAGAIN or -EINTR in case e.g signal pending or congestion,
+ * -ENOMEM in case we could not allocate a page, or 0.
+ * cc->migrate_pfn will contain the next pfn to scan.
*
* The pages are isolated on cc->migratepages list (not required to be empty),
- * and cc->nr_migratepages is updated accordingly. The cc->migrate_pfn field
- * is neither read nor updated.
+ * and cc->nr_migratepages is updated accordingly.
*/
-static unsigned long
+static int
isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
unsigned long end_pfn, isolate_mode_t isolate_mode)
{
bool skip_on_failure = false;
unsigned long next_skip_pfn = 0;
bool skip_updated = false;
+ int ret = 0;
+
+ cc->migrate_pfn = low_pfn;
/*
* Ensure that there are not too many pages isolated from the LRU
while (unlikely(too_many_isolated(pgdat))) {
/* stop isolation if there are still pages not migrated */
if (cc->nr_migratepages)
- return 0;
+ return -EAGAIN;
/* async migration should just abort */
if (cc->mode == MIGRATE_ASYNC)
- return 0;
+ return -EAGAIN;
congestion_wait(BLK_RW_ASYNC, HZ/10);
if (fatal_signal_pending(current))
- return 0;
+ return -EINTR;
}
cond_resched();
if (fatal_signal_pending(current)) {
cc->contended = true;
+ ret = -EINTR;
- low_pfn = 0;
goto fatal_pending;
}
valid_page = page;
}
+ if (PageHuge(page) && cc->alloc_contig) {
+ ret = isolate_or_dissolve_huge_page(page, &cc->migratepages);
+
+ /*
+ * Fail isolation in case isolate_or_dissolve_huge_page()
+ * reports an error. In case of -ENOMEM, abort right away.
+ */
+ if (ret < 0) {
+ /* Do not report -EBUSY down the chain */
+ if (ret == -EBUSY)
+ ret = 0;
+ low_pfn += (1UL << compound_order(page)) - 1;
+ goto isolate_fail;
+ }
+
+ if (PageHuge(page)) {
+ /*
+ * Hugepage was successfully isolated and placed
+ * on the cc->migratepages list.
+ */
+ low_pfn += compound_nr(page) - 1;
+ goto isolate_success_no_list;
+ }
+
+ /*
+ * Ok, the hugepage was dissolved. Now these pages are
+ * Buddy and cannot be re-allocated because they are
+ * isolated. Fall-through as the check below handles
+ * Buddy pages.
+ */
+ }
+
/*
* Skip if free. We read page order here without zone lock
* which is generally unsafe, but the race window is small and
isolate_success:
list_add(&page->lru, &cc->migratepages);
+isolate_success_no_list:
cc->nr_migratepages += compound_nr(page);
nr_isolated += compound_nr(page);
put_page(page);
isolate_fail:
- if (!skip_on_failure)
+ if (!skip_on_failure && ret != -ENOMEM)
continue;
/*
*/
next_skip_pfn += 1UL << cc->order;
}
+
+ if (ret == -ENOMEM)
+ break;
}
/*
if (nr_isolated)
count_compact_events(COMPACTISOLATED, nr_isolated);
- return low_pfn;
+ cc->migrate_pfn = low_pfn;
+
+ return ret;
}
/**
* @start_pfn: The first PFN to start isolating.
* @end_pfn: The one-past-last PFN.
*
- * Returns zero if isolation fails fatally due to e.g. pending signal.
- * Otherwise, function returns one-past-the-last PFN of isolated page
- * (which may be greater than end_pfn if end fell in a middle of a THP page).
+ * Returns -EAGAIN when contented, -EINTR in case of a signal pending, -ENOMEM
+ * in case we could not allocate a page, or 0.
*/
-unsigned long
+int
isolate_migratepages_range(struct compact_control *cc, unsigned long start_pfn,
unsigned long end_pfn)
{
unsigned long pfn, block_start_pfn, block_end_pfn;
+ int ret = 0;
/* Scan block by block. First and last block may be incomplete */
pfn = start_pfn;
block_end_pfn, cc->zone))
continue;
- pfn = isolate_migratepages_block(cc, pfn, block_end_pfn,
- ISOLATE_UNEVICTABLE);
+ ret = isolate_migratepages_block(cc, pfn, block_end_pfn,
+ ISOLATE_UNEVICTABLE);
- if (!pfn)
+ if (ret)
break;
if (cc->nr_migratepages >= COMPACT_CLUSTER_MAX)
break;
}
- return pfn;
+ return ret;
}
#endif /* CONFIG_COMPACTION || CONFIG_CMA */
*/
for (; block_end_pfn <= cc->free_pfn;
fast_find_block = false,
- low_pfn = block_end_pfn,
+ cc->migrate_pfn = low_pfn = block_end_pfn,
block_start_pfn = block_end_pfn,
block_end_pfn += pageblock_nr_pages) {
}
/* Perform the isolation */
- low_pfn = isolate_migratepages_block(cc, low_pfn,
- block_end_pfn, isolate_mode);
-
- if (!low_pfn)
+ if (isolate_migratepages_block(cc, low_pfn, block_end_pfn,
+ isolate_mode))
return ISOLATE_ABORT;
/*
break;
}
- /* Record where migration scanner will be restarted. */
- cc->migrate_pfn = low_pfn;
-
return cc->nr_migratepages ? ISOLATE_SUCCESS : ISOLATE_NONE;
}
unsigned int wmark_low;
/*
- * Cap the low watermak to avoid excessive compaction
- * activity in case a user sets the proactivess tunable
+ * Cap the low watermark to avoid excessive compaction
+ * activity in case a user sets the proactiveness tunable
* close to 100 (maximum).
*/
wmark_low = max(100U - sysctl_compaction_proactiveness, 5U);
trace_mm_compaction_begin(start_pfn, cc->migrate_pfn,
cc->free_pfn, end_pfn, sync);
- migrate_prep_local();
+ /* lru_add_drain_all could be expensive with involving other CPUs */
+ lru_add_drain();
while ((ret = compact_finished(cc)) == COMPACT_CONTINUE) {
int err;
*/
WRITE_ONCE(current->capture_control, NULL);
*capture = READ_ONCE(capc.page);
+ /*
+ * Technically, it is also possible that compaction is skipped but
+ * the page is still captured out of luck(IRQ came and freed the page).
+ * Returning COMPACT_SUCCESS in such cases helps in properly accounting
+ * the COMPACT[STALL|FAIL] when compaction is skipped.
+ */
+ if (*capture)
+ ret = COMPACT_SUCCESS;
return ret;
}
compact_node(nid);
}
-/* The written value is actually unused, all memory is compacted */
-int sysctl_compact_memory;
-
/*
* Tunable for proactive compaction. It determines how
* aggressively the kernel should compact memory in the
*/
static int kcompactd(void *p)
{
- pg_data_t *pgdat = (pg_data_t*)p;
+ pg_data_t *pgdat = (pg_data_t *)p;
struct task_struct *tsk = current;
unsigned int proactive_defer = 0;
projects / linux-2.6-microblaze.git / blobdiff