BUG_ON(PageActive(page));
sc->nr_scanned++;
+
+ if (!sc->may_swap && page_mapped(page))
+ goto keep_locked;
+
/* Double the slab pressure for mapped and swapcache pages */
if (page_mapped(page) || PageSwapCache(page))
sc->nr_scanned++;
struct address_space *mapping = page_mapping(page);
if (page_mapped(page) && mapping)
- if (try_to_unmap(page, 0) != SWAP_SUCCESS)
+ if (try_to_unmap(page, 1) != SWAP_SUCCESS)
goto unlock_retry;
if (PageDirty(page)) {
* pages are swapped out.
*
* The function returns after 10 attempts or if no pages
- * are movable anymore because t has become empty
+ * are movable anymore because to has become empty
* or no retryable pages exist anymore.
*
* Return: Number of pages not migrated when "to" ran empty.
goto unlock_both;
if (mapping->a_ops->migratepage) {
+ /*
+ * Most pages have a mapping and most filesystems
+ * should provide a migration function. Anonymous
+ * pages are part of swap space which also has its
+ * own migration function. This is the most common
+ * path for page migration.
+ */
rc = mapping->a_ops->migratepage(newpage, page);
goto unlock_both;
}
/*
- * Trigger writeout if page is dirty
+ * Default handling if a filesystem does not provide
+ * a migration function. We can only migrate clean
+ * pages so try to write out any dirty pages first.
*/
if (PageDirty(page)) {
switch (pageout(page, mapping)) {
; /* try to migrate the page below */
}
}
+
/*
- * If we have no buffer or can release the buffer
- * then do a simple migration.
+ * Buffers are managed in a filesystem specific way.
+ * We must have no buffers or drop them.
*/
if (!page_has_buffers(page) ||
try_to_release_page(page, GFP_KERNEL)) {
* swap them out.
*/
if (pass > 4) {
+ /*
+ * Persistently unable to drop buffers..... As a
+ * measure of last resort we fall back to
+ * swap_page().
+ */
unlock_page(newpage);
newpage = NULL;
rc = swap_page(page);
struct page *page;
struct pagevec pvec;
int reclaim_mapped = 0;
- long mapped_ratio;
- long distress;
- long swap_tendency;
+
+ if (unlikely(sc->may_swap)) {
+ long mapped_ratio;
+ long distress;
+ long swap_tendency;
+
+ /*
+ * `distress' is a measure of how much trouble we're having
+ * reclaiming pages. 0 -> no problems. 100 -> great trouble.
+ */
+ distress = 100 >> zone->prev_priority;
+
+ /*
+ * The point of this algorithm is to decide when to start
+ * reclaiming mapped memory instead of just pagecache. Work out
+ * how much memory
+ * is mapped.
+ */
+ mapped_ratio = (sc->nr_mapped * 100) / total_memory;
+
+ /*
+ * Now decide how much we really want to unmap some pages. The
+ * mapped ratio is downgraded - just because there's a lot of
+ * mapped memory doesn't necessarily mean that page reclaim
+ * isn't succeeding.
+ *
+ * The distress ratio is important - we don't want to start
+ * going oom.
+ *
+ * A 100% value of vm_swappiness overrides this algorithm
+ * altogether.
+ */
+ swap_tendency = mapped_ratio / 2 + distress + vm_swappiness;
+
+ /*
+ * Now use this metric to decide whether to start moving mapped
+ * memory onto the inactive list.
+ */
+ if (swap_tendency >= 100)
+ reclaim_mapped = 1;
+ }
lru_add_drain();
spin_lock_irq(&zone->lru_lock);
zone->nr_active -= pgmoved;
spin_unlock_irq(&zone->lru_lock);
- /*
- * `distress' is a measure of how much trouble we're having reclaiming
- * pages. 0 -> no problems. 100 -> great trouble.
- */
- distress = 100 >> zone->prev_priority;
-
- /*
- * The point of this algorithm is to decide when to start reclaiming
- * mapped memory instead of just pagecache. Work out how much memory
- * is mapped.
- */
- mapped_ratio = (sc->nr_mapped * 100) / total_memory;
-
- /*
- * Now decide how much we really want to unmap some pages. The mapped
- * ratio is downgraded - just because there's a lot of mapped memory
- * doesn't necessarily mean that page reclaim isn't succeeding.
- *
- * The distress ratio is important - we don't want to start going oom.
- *
- * A 100% value of vm_swappiness overrides this algorithm altogether.
- */
- swap_tendency = mapped_ratio / 2 + distress + vm_swappiness;
-
- /*
- * Now use this metric to decide whether to start moving mapped memory
- * onto the inactive list.
- */
- if (swap_tendency >= 100)
- reclaim_mapped = 1;
-
while (!list_empty(&l_hold)) {
cond_resched();
page = lru_to_page(&l_hold);
sc.nr_reclaimed = 0;
sc.priority = priority;
sc.swap_cluster_max = nr_pages? nr_pages : SWAP_CLUSTER_MAX;
- atomic_inc(&zone->reclaim_in_progress);
shrink_zone(zone, &sc);
- atomic_dec(&zone->reclaim_in_progress);
reclaim_state->reclaimed_slab = 0;
nr_slab = shrink_slab(sc.nr_scanned, GFP_KERNEL,
lru_pages);
sc.swap_cluster_max = SWAP_CLUSTER_MAX;
cond_resched();
- p->flags |= PF_MEMALLOC;
+ /*
+ * We need to be able to allocate from the reserves for RECLAIM_SWAP
+ * and we also need to be able to write out pages for RECLAIM_WRITE
+ * and RECLAIM_SWAP.
+ */
+ p->flags |= PF_MEMALLOC | PF_SWAPWRITE;
reclaim_state.reclaimed_slab = 0;
p->reclaim_state = &reclaim_state;
* a long time.
*/
shrink_slab(sc.nr_scanned, gfp_mask, order);
- sc.nr_reclaimed = 1; /* Avoid getting the off node timeout */
}
p->reclaim_state = NULL;
- current->flags &= ~PF_MEMALLOC;
+ current->flags &= ~(PF_MEMALLOC | PF_SWAPWRITE);
if (sc.nr_reclaimed == 0)
zone->last_unsuccessful_zone_reclaim = jiffies;
projects / linux-2.6-omap-h63xx.git / blobdiff