[patch 3/3] mm: vmscan: clean up struct scan_control
From: Johannes Weiner
Date: Mon Jul 14 2014 - 09:21:23 EST
Reorder the members by input and output, then turn the individual
integers for may_writepage, may_unmap, may_swap, compaction_ready,
hibernation_mode into flags that fit into a single integer.
Stack delta: +72/-296 -224 old new delta
kswapd 104 176 +72
try_to_free_pages 80 56 -24
try_to_free_mem_cgroup_pages 80 56 -24
shrink_all_memory 88 64 -24
reclaim_clean_pages_from_list 168 144 -24
mem_cgroup_shrink_node_zone 104 80 -24
__zone_reclaim 176 152 -24
balance_pgdat 152 - -152
text data bss dec hex filename
38151 5641 16 43808 ab20 mm/vmscan.o.old
38047 5641 16 43704 aab8 mm/vmscan.o
Suggested-by: Mel Gorman <mgorman@xxxxxxx>
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
---
mm/vmscan.c | 158 ++++++++++++++++++++++++++++++------------------------------
1 file changed, 78 insertions(+), 80 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index c28b8981e56a..73d8e69ff3eb 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -58,36 +58,28 @@
#define CREATE_TRACE_POINTS
#include <trace/events/vmscan.h>
-struct scan_control {
- /* Incremented by the number of inactive pages that were scanned */
- unsigned long nr_scanned;
-
- /* Number of pages freed so far during a call to shrink_zones() */
- unsigned long nr_reclaimed;
-
- /* One of the zones is ready for compaction */
- int compaction_ready;
+/* Scan control flags */
+#define MAY_WRITEPAGE 0x1
+#define MAY_UNMAP 0x2
+#define MAY_SWAP 0x4
+#define MAY_SKIP_CONGESTION 0x8
+#define COMPACTION_READY 0x10
+struct scan_control {
/* How many pages shrink_list() should reclaim */
unsigned long nr_to_reclaim;
- unsigned long hibernation_mode;
-
/* This context's GFP mask */
gfp_t gfp_mask;
- int may_writepage;
-
- /* Can mapped pages be reclaimed? */
- int may_unmap;
-
- /* Can pages be swapped as part of reclaim? */
- int may_swap;
-
+ /* Allocation order */
int order;
- /* Scan (total_size >> priority) pages at once */
- int priority;
+ /*
+ * Nodemask of nodes allowed by the caller. If NULL, all nodes
+ * are scanned.
+ */
+ nodemask_t *nodemask;
/*
* The memory cgroup that hit its limit and as a result is the
@@ -95,11 +87,17 @@ struct scan_control {
*/
struct mem_cgroup *target_mem_cgroup;
- /*
- * Nodemask of nodes allowed by the caller. If NULL, all nodes
- * are scanned.
- */
- nodemask_t *nodemask;
+ /* Scan (total_size >> priority) pages at once */
+ int priority;
+
+ /* Scan control flags; see above */
+ unsigned int flags;
+
+ /* Incremented by the number of inactive pages that were scanned */
+ unsigned long nr_scanned;
+
+ /* Number of pages freed so far during a call to shrink_zones() */
+ unsigned long nr_reclaimed;
};
#define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru))
@@ -840,7 +838,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
if (unlikely(!page_evictable(page)))
goto cull_mlocked;
- if (!sc->may_unmap && page_mapped(page))
+ if (!(sc->flags & MAY_UNMAP) && page_mapped(page))
goto keep_locked;
/* Double the slab pressure for mapped and swapcache pages */
@@ -1014,7 +1012,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
goto keep_locked;
if (!may_enter_fs)
goto keep_locked;
- if (!sc->may_writepage)
+ if (!(sc->flags & MAY_WRITEPAGE))
goto keep_locked;
/* Page is dirty, try to write it out here */
@@ -1146,7 +1144,7 @@ unsigned long reclaim_clean_pages_from_list(struct zone *zone,
struct scan_control sc = {
.gfp_mask = GFP_KERNEL,
.priority = DEF_PRIORITY,
- .may_unmap = 1,
+ .flags = MAY_UNMAP,
};
unsigned long ret, dummy1, dummy2, dummy3, dummy4, dummy5;
struct page *page, *next;
@@ -1489,9 +1487,9 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
lru_add_drain();
- if (!sc->may_unmap)
+ if (!(sc->flags & MAY_UNMAP))
isolate_mode |= ISOLATE_UNMAPPED;
- if (!sc->may_writepage)
+ if (!(sc->flags & MAY_WRITEPAGE))
isolate_mode |= ISOLATE_CLEAN;
spin_lock_irq(&zone->lru_lock);
@@ -1593,7 +1591,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
* is congested. Allow kswapd to continue until it starts encountering
* unqueued dirty pages or cycling through the LRU too quickly.
*/
- if (!sc->hibernation_mode && !current_is_kswapd() &&
+ if (!(sc->flags & MAY_SKIP_CONGESTION) && !current_is_kswapd() &&
current_may_throttle())
wait_iff_congested(zone, BLK_RW_ASYNC, HZ/10);
@@ -1683,9 +1681,9 @@ static void shrink_active_list(unsigned long nr_to_scan,
lru_add_drain();
- if (!sc->may_unmap)
+ if (!(sc->flags & MAY_UNMAP))
isolate_mode |= ISOLATE_UNMAPPED;
- if (!sc->may_writepage)
+ if (!(sc->flags & MAY_WRITEPAGE))
isolate_mode |= ISOLATE_CLEAN;
spin_lock_irq(&zone->lru_lock);
@@ -1897,7 +1895,7 @@ static void get_scan_count(struct lruvec *lruvec, int swappiness,
force_scan = true;
/* If we have no swap space, do not bother scanning anon pages. */
- if (!sc->may_swap || (get_nr_swap_pages() <= 0)) {
+ if (!(sc->flags & MAY_SWAP) || (get_nr_swap_pages() <= 0)) {
scan_balance = SCAN_FILE;
goto out;
}
@@ -2406,7 +2404,7 @@ static bool shrink_zones(struct zonelist *zonelist, struct scan_control *sc)
sc->order > PAGE_ALLOC_COSTLY_ORDER &&
zonelist_zone_idx(z) <= requested_highidx &&
compaction_ready(zone, sc->order)) {
- sc->compaction_ready = true;
+ sc->flags |= COMPACTION_READY;
continue;
}
@@ -2496,7 +2494,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
if (sc->nr_reclaimed >= sc->nr_to_reclaim)
break;
- if (sc->compaction_ready)
+ if (sc->flags & COMPACTION_READY)
break;
/*
@@ -2504,7 +2502,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
* writepage even in laptop mode.
*/
if (sc->priority < DEF_PRIORITY - 2)
- sc->may_writepage = 1;
+ sc->flags |= MAY_WRITEPAGE;
/*
* Try to write back as many pages as we just scanned. This
@@ -2517,7 +2515,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
if (total_scanned > writeback_threshold) {
wakeup_flusher_threads(laptop_mode ? 0 : total_scanned,
WB_REASON_TRY_TO_FREE_PAGES);
- sc->may_writepage = 1;
+ sc->flags |= MAY_WRITEPAGE;
}
} while (--sc->priority >= 0);
@@ -2527,7 +2525,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
return sc->nr_reclaimed;
/* Aborted reclaim to try compaction? don't OOM, then */
- if (sc->compaction_ready)
+ if (sc->flags & COMPACTION_READY)
return 1;
/* Any of the zones still reclaimable? Don't OOM. */
@@ -2668,17 +2666,17 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
{
unsigned long nr_reclaimed;
struct scan_control sc = {
- .gfp_mask = (gfp_mask = memalloc_noio_flags(gfp_mask)),
- .may_writepage = !laptop_mode,
.nr_to_reclaim = SWAP_CLUSTER_MAX,
- .may_unmap = 1,
- .may_swap = 1,
+ .gfp_mask = (gfp_mask = memalloc_noio_flags(gfp_mask)),
.order = order,
- .priority = DEF_PRIORITY,
- .target_mem_cgroup = NULL,
.nodemask = nodemask,
+ .priority = DEF_PRIORITY,
+ .flags = MAY_UNMAP | MAY_SWAP,
};
+ if (!laptop_mode)
+ sc.flags |= MAY_WRITEPAGE;
+
/*
* Do not enter reclaim if fatal signal was delivered while throttled.
* 1 is returned so that the page allocator does not OOM kill at this
@@ -2688,7 +2686,7 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
return 1;
trace_mm_vmscan_direct_reclaim_begin(order,
- sc.may_writepage,
+ sc.flags & MAY_WRITEPAGE,
gfp_mask);
nr_reclaimed = do_try_to_free_pages(zonelist, &sc);
@@ -2706,23 +2704,22 @@ unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *memcg,
unsigned long *nr_scanned)
{
struct scan_control sc = {
- .nr_scanned = 0,
.nr_to_reclaim = SWAP_CLUSTER_MAX,
- .may_writepage = !laptop_mode,
- .may_unmap = 1,
- .may_swap = !noswap,
- .order = 0,
- .priority = 0,
+ .gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) |
+ (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK),
.target_mem_cgroup = memcg,
+ .flags = MAY_UNMAP,
};
struct lruvec *lruvec = mem_cgroup_zone_lruvec(zone, memcg);
int swappiness = mem_cgroup_swappiness(memcg);
- sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) |
- (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK);
+ if (!laptop_mode)
+ sc.flags |= MAY_WRITEPAGE;
+ if (!noswap)
+ sc.flags |= MAY_SWAP;
trace_mm_vmscan_memcg_softlimit_reclaim_begin(sc.order,
- sc.may_writepage,
+ sc.flags & MAY_WRITEPAGE,
sc.gfp_mask);
/*
@@ -2748,18 +2745,19 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
unsigned long nr_reclaimed;
int nid;
struct scan_control sc = {
- .may_writepage = !laptop_mode,
- .may_unmap = 1,
- .may_swap = !noswap,
.nr_to_reclaim = SWAP_CLUSTER_MAX,
- .order = 0,
- .priority = DEF_PRIORITY,
- .target_mem_cgroup = memcg,
- .nodemask = NULL, /* we don't care the placement */
.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) |
- (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK),
+ (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK),
+ .target_mem_cgroup = memcg,
+ .priority = DEF_PRIORITY,
+ .flags = MAY_UNMAP,
};
+ if (!laptop_mode)
+ sc.flags |= MAY_WRITEPAGE;
+ if (!noswap)
+ sc.flags |= MAY_SWAP;
+
/*
* Unlike direct reclaim via alloc_pages(), memcg's reclaim doesn't
* take care of from where we get pages. So the node where we start the
@@ -2770,7 +2768,7 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
zonelist = NODE_DATA(nid)->node_zonelists;
trace_mm_vmscan_memcg_reclaim_begin(0,
- sc.may_writepage,
+ sc.flags & MAY_WRITEPAGE,
sc.gfp_mask);
nr_reclaimed = do_try_to_free_pages(zonelist, &sc);
@@ -3015,15 +3013,15 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
unsigned long nr_soft_scanned;
struct scan_control sc = {
.gfp_mask = GFP_KERNEL,
- .priority = DEF_PRIORITY,
- .may_unmap = 1,
- .may_swap = 1,
- .may_writepage = !laptop_mode,
.order = order,
- .target_mem_cgroup = NULL,
+ .priority = DEF_PRIORITY,
+ .flags = MAY_UNMAP | MAY_SWAP,
};
count_vm_event(PAGEOUTRUN);
+ if (!laptop_mode)
+ sc.flags |= MAY_WRITEPAGE;
+
do {
unsigned long lru_pages = 0;
unsigned long nr_attempted = 0;
@@ -3104,7 +3102,7 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
* even in laptop mode.
*/
if (sc.priority < DEF_PRIORITY - 2)
- sc.may_writepage = 1;
+ sc.flags |= MAY_WRITEPAGE;
/*
* Now scan the zone in the dma->highmem direction, stopping
@@ -3401,14 +3399,11 @@ unsigned long shrink_all_memory(unsigned long nr_to_reclaim)
{
struct reclaim_state reclaim_state;
struct scan_control sc = {
- .gfp_mask = GFP_HIGHUSER_MOVABLE,
- .may_swap = 1,
- .may_unmap = 1,
- .may_writepage = 1,
.nr_to_reclaim = nr_to_reclaim,
- .hibernation_mode = 1,
- .order = 0,
+ .gfp_mask = GFP_HIGHUSER_MOVABLE,
.priority = DEF_PRIORITY,
+ .flags = MAY_WRITEPAGE | MAY_UNMAP | MAY_SWAP |
+ MAY_SKIP_CONGESTION,
};
struct zonelist *zonelist = node_zonelist(numa_node_id(), sc.gfp_mask);
struct task_struct *p = current;
@@ -3588,19 +3583,22 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
struct task_struct *p = current;
struct reclaim_state reclaim_state;
struct scan_control sc = {
- .may_writepage = !!(zone_reclaim_mode & RECLAIM_WRITE),
- .may_unmap = !!(zone_reclaim_mode & RECLAIM_SWAP),
- .may_swap = 1,
.nr_to_reclaim = max(nr_pages, SWAP_CLUSTER_MAX),
.gfp_mask = (gfp_mask = memalloc_noio_flags(gfp_mask)),
.order = order,
.priority = ZONE_RECLAIM_PRIORITY,
+ .flags = MAY_SWAP,
};
struct shrink_control shrink = {
.gfp_mask = sc.gfp_mask,
};
unsigned long nr_slab_pages0, nr_slab_pages1;
+ if (zone_reclaim_mode & RECLAIM_WRITE)
+ sc.flags |= MAY_WRITEPAGE;
+ if (zone_reclaim_mode & RECLAIM_SWAP)
+ sc.flags |= MAY_UNMAP;
+
cond_resched();
/*
* We need to be able to allocate from the reserves for RECLAIM_SWAP
--
2.0.0
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/