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Message-Id: <20210520065355.2736558-7-yuzhao@google.com>
Date: Thu, 20 May 2021 00:53:47 -0600
From: Yu Zhao <yuzhao@...gle.com>
To: linux-mm@...ck.org
Cc: Alex Shi <alexs@...nel.org>, Andi Kleen <ak@...ux.intel.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Dave Chinner <david@...morbit.com>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Donald Carr <sirspudd@...il.com>,
Hillf Danton <hdanton@...a.com>, Jens Axboe <axboe@...nel.dk>,
Johannes Weiner <hannes@...xchg.org>,
Jonathan Corbet <corbet@....net>,
Joonsoo Kim <iamjoonsoo.kim@....com>,
Konstantin Kharlamov <hi-angel@...dex.ru>,
Marcus Seyfarth <m.seyfarth@...il.com>,
Matthew Wilcox <willy@...radead.org>,
Mel Gorman <mgorman@...e.de>,
Miaohe Lin <linmiaohe@...wei.com>,
Michael Larabel <michael@...haellarabel.com>,
Michal Hocko <mhocko@...e.com>,
Michel Lespinasse <michel@...pinasse.org>,
Rik van Riel <riel@...riel.com>,
Roman Gushchin <guro@...com>,
Tim Chen <tim.c.chen@...ux.intel.com>,
Vlastimil Babka <vbabka@...e.cz>,
Yang Shi <shy828301@...il.com>,
Ying Huang <ying.huang@...el.com>, Zi Yan <ziy@...dia.com>,
linux-kernel@...r.kernel.org, lkp@...ts.01.org,
page-reclaim@...gle.com, Yu Zhao <yuzhao@...gle.com>,
Konstantin Kharlamov <Hi-Angel@...dex.ru>
Subject: [PATCH v3 06/14] mm/workingset.c: refactor pack_shadow() and unpack_shadow()
This patches moves the bucket order and PageWorkingset() out of
pack_shadow() and unpack_shadow(). It has no merits on its own but
makes the upcoming changes to mm/workingset.c less diffy.
Signed-off-by: Yu Zhao <yuzhao@...gle.com>
Tested-by: Konstantin Kharlamov <Hi-Angel@...dex.ru>
---
mm/workingset.c | 53 ++++++++++++++++++++-----------------------------
1 file changed, 22 insertions(+), 31 deletions(-)
diff --git a/mm/workingset.c b/mm/workingset.c
index b7cdeca5a76d..edb8aed2587e 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -168,9 +168,9 @@
* refault distance will immediately activate the refaulting page.
*/
-#define EVICTION_SHIFT ((BITS_PER_LONG - BITS_PER_XA_VALUE) + \
- 1 + NODES_SHIFT + MEM_CGROUP_ID_SHIFT)
-#define EVICTION_MASK (~0UL >> EVICTION_SHIFT)
+#define EVICTION_SHIFT (BITS_PER_XA_VALUE - MEM_CGROUP_ID_SHIFT - NODES_SHIFT)
+#define EVICTION_MASK (BIT(EVICTION_SHIFT) - 1)
+#define WORKINGSET_WIDTH 1
/*
* Eviction timestamps need to be able to cover the full range of
@@ -182,36 +182,23 @@
*/
static unsigned int bucket_order __read_mostly;
-static void *pack_shadow(int memcgid, pg_data_t *pgdat, unsigned long eviction,
- bool workingset)
+static void *pack_shadow(int memcg_id, struct pglist_data *pgdat, unsigned long val)
{
- eviction >>= bucket_order;
- eviction &= EVICTION_MASK;
- eviction = (eviction << MEM_CGROUP_ID_SHIFT) | memcgid;
- eviction = (eviction << NODES_SHIFT) | pgdat->node_id;
- eviction = (eviction << 1) | workingset;
+ val = (val << MEM_CGROUP_ID_SHIFT) | memcg_id;
+ val = (val << NODES_SHIFT) | pgdat->node_id;
- return xa_mk_value(eviction);
+ return xa_mk_value(val);
}
-static void unpack_shadow(void *shadow, int *memcgidp, pg_data_t **pgdat,
- unsigned long *evictionp, bool *workingsetp)
+static unsigned long unpack_shadow(void *shadow, int *memcg_id, struct pglist_data **pgdat)
{
- unsigned long entry = xa_to_value(shadow);
- int memcgid, nid;
- bool workingset;
+ unsigned long val = xa_to_value(shadow);
- workingset = entry & 1;
- entry >>= 1;
- nid = entry & ((1UL << NODES_SHIFT) - 1);
- entry >>= NODES_SHIFT;
- memcgid = entry & ((1UL << MEM_CGROUP_ID_SHIFT) - 1);
- entry >>= MEM_CGROUP_ID_SHIFT;
+ *pgdat = NODE_DATA(val & (BIT(NODES_SHIFT) - 1));
+ val >>= NODES_SHIFT;
+ *memcg_id = val & (BIT(MEM_CGROUP_ID_SHIFT) - 1);
- *memcgidp = memcgid;
- *pgdat = NODE_DATA(nid);
- *evictionp = entry << bucket_order;
- *workingsetp = workingset;
+ return val >> MEM_CGROUP_ID_SHIFT;
}
/**
@@ -266,8 +253,10 @@ void *workingset_eviction(struct page *page, struct mem_cgroup *target_memcg)
/* XXX: target_memcg can be NULL, go through lruvec */
memcgid = mem_cgroup_id(lruvec_memcg(lruvec));
eviction = atomic_long_read(&lruvec->nonresident_age);
+ eviction >>= bucket_order;
+ eviction = (eviction << WORKINGSET_WIDTH) | PageWorkingset(page);
workingset_age_nonresident(lruvec, thp_nr_pages(page));
- return pack_shadow(memcgid, pgdat, eviction, PageWorkingset(page));
+ return pack_shadow(memcgid, pgdat, eviction);
}
/**
@@ -294,7 +283,7 @@ void workingset_refault(struct page *page, void *shadow)
bool workingset;
int memcgid;
- unpack_shadow(shadow, &memcgid, &pgdat, &eviction, &workingset);
+ eviction = unpack_shadow(shadow, &memcgid, &pgdat);
rcu_read_lock();
/*
@@ -318,6 +307,8 @@ void workingset_refault(struct page *page, void *shadow)
goto out;
eviction_lruvec = mem_cgroup_lruvec(eviction_memcg, pgdat);
refault = atomic_long_read(&eviction_lruvec->nonresident_age);
+ workingset = eviction & (BIT(WORKINGSET_WIDTH) - 1);
+ eviction = (eviction >> WORKINGSET_WIDTH) << bucket_order;
/*
* Calculate the refault distance
@@ -335,7 +326,7 @@ void workingset_refault(struct page *page, void *shadow)
* longest time, so the occasional inappropriate activation
* leading to pressure on the active list is not a problem.
*/
- refault_distance = (refault - eviction) & EVICTION_MASK;
+ refault_distance = (refault - eviction) & (EVICTION_MASK >> WORKINGSET_WIDTH);
/*
* The activation decision for this page is made at the level
@@ -593,7 +584,7 @@ static int __init workingset_init(void)
unsigned int max_order;
int ret;
- BUILD_BUG_ON(BITS_PER_LONG < EVICTION_SHIFT);
+ BUILD_BUG_ON(EVICTION_SHIFT < WORKINGSET_WIDTH);
/*
* Calculate the eviction bucket size to cover the longest
* actionable refault distance, which is currently half of
@@ -601,7 +592,7 @@ static int __init workingset_init(void)
* some more pages at runtime, so keep working with up to
* double the initial memory by using totalram_pages as-is.
*/
- timestamp_bits = BITS_PER_LONG - EVICTION_SHIFT;
+ timestamp_bits = EVICTION_SHIFT - WORKINGSET_WIDTH;
max_order = fls_long(totalram_pages() - 1);
if (max_order > timestamp_bits)
bucket_order = max_order - timestamp_bits;
--
2.31.1.751.gd2f1c929bd-goog
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