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Message-ID: <20140902222653.GA20186@cmpxchg.org>
Date: Tue, 2 Sep 2014 18:26:53 -0400
From: Johannes Weiner <hannes@...xchg.org>
To: David Rientjes <rientjes@...gle.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
Mel Gorman <mgorman@...e.de>, linux-mm@...ck.org,
linux-kernel@...r.kernel.org
Subject: Re: [patch] mm: clean up zone flags
On Tue, Sep 02, 2014 at 02:42:14PM -0700, David Rientjes wrote:
> On Tue, 2 Sep 2014, Johannes Weiner wrote:
> > @@ -631,7 +631,7 @@ long wait_iff_congested(struct zone *zone, int sync, long timeout)
> > * of sleeping on the congestion queue
> > */
> > if (atomic_read(&nr_bdi_congested[sync]) == 0 ||
> > - !zone_is_reclaim_congested(zone)) {
> > + test_bit(ZONE_CONGESTED, &zone->flags)) {
> > cond_resched();
> >
> > /* In case we scheduled, work out time remaining */
>
> That's not equivalent.
>
> [snip]
>
> > diff --git a/mm/vmscan.c b/mm/vmscan.c
> > index 2836b5373b2e..590a92bec6a4 100644
> > --- a/mm/vmscan.c
> > +++ b/mm/vmscan.c
> > @@ -920,7 +920,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
> > /* Case 1 above */
> > if (current_is_kswapd() &&
> > PageReclaim(page) &&
> > - zone_is_reclaim_writeback(zone)) {
> > + test_bit(ZONE_WRITEBACK, &zone->flags)) {
> > nr_immediate++;
> > goto keep_locked;
> >
> > @@ -1002,7 +1002,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
> > */
> > if (page_is_file_cache(page) &&
> > (!current_is_kswapd() ||
> > - !zone_is_reclaim_dirty(zone))) {
> > + test_bit(ZONE_DIRTY, &zone->flags))) {
> > /*
> > * Immediately reclaim when written back.
> > * Similar in principal to deactivate_page()
>
> Nor is this.
>
> After fixed, for the oom killer bits:
>
> Acked-by: David Rientjes <rientjes@...gle.com>
>
> since this un-obscurification is most welcome.
Yikes, thanks for catching those and acking. Updated patch:
---
>From 2420ad16df0634e073ad327f0f72472d9b03762b Mon Sep 17 00:00:00 2001
From: Johannes Weiner <hannes@...xchg.org>
Date: Tue, 2 Sep 2014 10:14:36 -0400
Subject: [patch] mm: clean up zone flags
Page reclaim tests zone_is_reclaim_dirty(), but the site that actually
sets this state does zone_set_flag(zone, ZONE_TAIL_LRU_DIRTY), sending
the reader through layers indirection just to track down a simple bit.
Remove all zone flag wrappers and just use bitops against zone->flags
directly. It's just as readable and the lines are barely any longer.
Also rename ZONE_TAIL_LRU_DIRTY to ZONE_DIRTY to match ZONE_WRITEBACK,
and remove the zone_flags_t typedef.
Signed-off-by: Johannes Weiner <hannes@...xchg.org>
Acked-by: David Rientjes <rientjes@...gle.com>
---
include/linux/mmzone.h | 51 +++-----------------------------------------------
mm/backing-dev.c | 2 +-
mm/oom_kill.c | 6 +++---
mm/page_alloc.c | 8 ++++----
mm/vmscan.c | 28 +++++++++++++--------------
5 files changed, 25 insertions(+), 70 deletions(-)
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 318df7051850..48bf12ef6620 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -521,13 +521,13 @@ struct zone {
atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
} ____cacheline_internodealigned_in_smp;
-typedef enum {
+enum zone_flags {
ZONE_RECLAIM_LOCKED, /* prevents concurrent reclaim */
ZONE_OOM_LOCKED, /* zone is in OOM killer zonelist */
ZONE_CONGESTED, /* zone has many dirty pages backed by
* a congested BDI
*/
- ZONE_TAIL_LRU_DIRTY, /* reclaim scanning has recently found
+ ZONE_DIRTY, /* reclaim scanning has recently found
* many dirty file pages at the tail
* of the LRU.
*/
@@ -535,52 +535,7 @@ typedef enum {
* many pages under writeback
*/
ZONE_FAIR_DEPLETED, /* fair zone policy batch depleted */
-} zone_flags_t;
-
-static inline void zone_set_flag(struct zone *zone, zone_flags_t flag)
-{
- set_bit(flag, &zone->flags);
-}
-
-static inline int zone_test_and_set_flag(struct zone *zone, zone_flags_t flag)
-{
- return test_and_set_bit(flag, &zone->flags);
-}
-
-static inline void zone_clear_flag(struct zone *zone, zone_flags_t flag)
-{
- clear_bit(flag, &zone->flags);
-}
-
-static inline int zone_is_reclaim_congested(const struct zone *zone)
-{
- return test_bit(ZONE_CONGESTED, &zone->flags);
-}
-
-static inline int zone_is_reclaim_dirty(const struct zone *zone)
-{
- return test_bit(ZONE_TAIL_LRU_DIRTY, &zone->flags);
-}
-
-static inline int zone_is_reclaim_writeback(const struct zone *zone)
-{
- return test_bit(ZONE_WRITEBACK, &zone->flags);
-}
-
-static inline int zone_is_reclaim_locked(const struct zone *zone)
-{
- return test_bit(ZONE_RECLAIM_LOCKED, &zone->flags);
-}
-
-static inline int zone_is_fair_depleted(const struct zone *zone)
-{
- return test_bit(ZONE_FAIR_DEPLETED, &zone->flags);
-}
-
-static inline int zone_is_oom_locked(const struct zone *zone)
-{
- return test_bit(ZONE_OOM_LOCKED, &zone->flags);
-}
+};
static inline unsigned long zone_end_pfn(const struct zone *zone)
{
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 1706cbbdf5f0..b27714f1b40f 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -631,7 +631,7 @@ long wait_iff_congested(struct zone *zone, int sync, long timeout)
* of sleeping on the congestion queue
*/
if (atomic_read(&nr_bdi_congested[sync]) == 0 ||
- !zone_is_reclaim_congested(zone)) {
+ !test_bit(ZONE_CONGESTED, &zone->flags)) {
cond_resched();
/* In case we scheduled, work out time remaining */
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 1e11df8fa7ec..bbf405a3a18f 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -565,7 +565,7 @@ bool oom_zonelist_trylock(struct zonelist *zonelist, gfp_t gfp_mask)
spin_lock(&zone_scan_lock);
for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask))
- if (zone_is_oom_locked(zone)) {
+ if (test_bit(ZONE_OOM_LOCKED, &zone->flags)) {
ret = false;
goto out;
}
@@ -575,7 +575,7 @@ bool oom_zonelist_trylock(struct zonelist *zonelist, gfp_t gfp_mask)
* call to oom_zonelist_trylock() doesn't succeed when it shouldn't.
*/
for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask))
- zone_set_flag(zone, ZONE_OOM_LOCKED);
+ set_bit(ZONE_OOM_LOCKED, &zone->flags);
out:
spin_unlock(&zone_scan_lock);
@@ -594,7 +594,7 @@ void oom_zonelist_unlock(struct zonelist *zonelist, gfp_t gfp_mask)
spin_lock(&zone_scan_lock);
for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask))
- zone_clear_flag(zone, ZONE_OOM_LOCKED);
+ clear_bit(ZONE_OOM_LOCKED, &zone->flags);
spin_unlock(&zone_scan_lock);
}
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 18cee0d4c8a2..f0eb97de6cad 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1613,8 +1613,8 @@ again:
__mod_zone_page_state(zone, NR_ALLOC_BATCH, -(1 << order));
if (zone_page_state(zone, NR_ALLOC_BATCH) == 0 &&
- !zone_is_fair_depleted(zone))
- zone_set_flag(zone, ZONE_FAIR_DEPLETED);
+ !test_bit(ZONE_FAIR_DEPLETED, &zone->flags))
+ set_bit(ZONE_FAIR_DEPLETED, &zone->flags);
__count_zone_vm_events(PGALLOC, zone, 1 << order);
zone_statistics(preferred_zone, zone, gfp_flags);
@@ -1934,7 +1934,7 @@ static void reset_alloc_batches(struct zone *preferred_zone)
mod_zone_page_state(zone, NR_ALLOC_BATCH,
high_wmark_pages(zone) - low_wmark_pages(zone) -
atomic_long_read(&zone->vm_stat[NR_ALLOC_BATCH]));
- zone_clear_flag(zone, ZONE_FAIR_DEPLETED);
+ clear_bit(ZONE_FAIR_DEPLETED, &zone->flags);
} while (zone++ != preferred_zone);
}
@@ -1985,7 +1985,7 @@ zonelist_scan:
if (alloc_flags & ALLOC_FAIR) {
if (!zone_local(preferred_zone, zone))
break;
- if (zone_is_fair_depleted(zone)) {
+ if (test_bit(ZONE_FAIR_DEPLETED, &zone->flags)) {
nr_fair_skipped++;
continue;
}
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 2836b5373b2e..a14f1642759c 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -920,7 +920,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
/* Case 1 above */
if (current_is_kswapd() &&
PageReclaim(page) &&
- zone_is_reclaim_writeback(zone)) {
+ test_bit(ZONE_WRITEBACK, &zone->flags)) {
nr_immediate++;
goto keep_locked;
@@ -1002,7 +1002,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
*/
if (page_is_file_cache(page) &&
(!current_is_kswapd() ||
- !zone_is_reclaim_dirty(zone))) {
+ !test_bit(ZONE_DIRTY, &zone->flags))) {
/*
* Immediately reclaim when written back.
* Similar in principal to deactivate_page()
@@ -1563,7 +1563,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
* are encountered in the nr_immediate check below.
*/
if (nr_writeback && nr_writeback == nr_taken)
- zone_set_flag(zone, ZONE_WRITEBACK);
+ set_bit(ZONE_WRITEBACK, &zone->flags);
/*
* memcg will stall in page writeback so only consider forcibly
@@ -1575,16 +1575,16 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
* backed by a congested BDI and wait_iff_congested will stall.
*/
if (nr_dirty && nr_dirty == nr_congested)
- zone_set_flag(zone, ZONE_CONGESTED);
+ set_bit(ZONE_CONGESTED, &zone->flags);
/*
* If dirty pages are scanned that are not queued for IO, it
* implies that flushers are not keeping up. In this case, flag
- * the zone ZONE_TAIL_LRU_DIRTY and kswapd will start writing
- * pages from reclaim context.
+ * the zone ZONE_DIRTY and kswapd will start writing pages from
+ * reclaim context.
*/
if (nr_unqueued_dirty == nr_taken)
- zone_set_flag(zone, ZONE_TAIL_LRU_DIRTY);
+ set_bit(ZONE_DIRTY, &zone->flags);
/*
* If kswapd scans pages marked marked for immediate
@@ -2978,7 +2978,7 @@ static bool kswapd_shrink_zone(struct zone *zone,
/* Account for the number of pages attempted to reclaim */
*nr_attempted += sc->nr_to_reclaim;
- zone_clear_flag(zone, ZONE_WRITEBACK);
+ clear_bit(ZONE_WRITEBACK, &zone->flags);
/*
* If a zone reaches its high watermark, consider it to be no longer
@@ -2988,8 +2988,8 @@ static bool kswapd_shrink_zone(struct zone *zone,
*/
if (zone_reclaimable(zone) &&
zone_balanced(zone, testorder, 0, classzone_idx)) {
- zone_clear_flag(zone, ZONE_CONGESTED);
- zone_clear_flag(zone, ZONE_TAIL_LRU_DIRTY);
+ clear_bit(ZONE_CONGESTED, &zone->flags);
+ clear_bit(ZONE_DIRTY, &zone->flags);
}
return sc->nr_scanned >= sc->nr_to_reclaim;
@@ -3080,8 +3080,8 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
* If balanced, clear the dirty and congested
* flags
*/
- zone_clear_flag(zone, ZONE_CONGESTED);
- zone_clear_flag(zone, ZONE_TAIL_LRU_DIRTY);
+ clear_bit(ZONE_CONGESTED, &zone->flags);
+ clear_bit(ZONE_DIRTY, &zone->flags);
}
}
@@ -3708,11 +3708,11 @@ int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
if (node_state(node_id, N_CPU) && node_id != numa_node_id())
return ZONE_RECLAIM_NOSCAN;
- if (zone_test_and_set_flag(zone, ZONE_RECLAIM_LOCKED))
+ if (test_and_set_bit(ZONE_RECLAIM_LOCKED, &zone->flags))
return ZONE_RECLAIM_NOSCAN;
ret = __zone_reclaim(zone, gfp_mask, order);
- zone_clear_flag(zone, ZONE_RECLAIM_LOCKED);
+ clear_bit(ZONE_RECLAIM_LOCKED, &zone->flags);
if (!ret)
count_vm_event(PGSCAN_ZONE_RECLAIM_FAILED);
--
2.0.4
--
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