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Message-ID: <20250901105128.14987-3-hans.holmberg@wdc.com>
Date: Mon, 1 Sep 2025 10:52:05 +0000
From: Hans Holmberg <Hans.Holmberg@....com>
To: "linux-xfs@...r.kernel.org" <linux-xfs@...r.kernel.org>
CC: Carlos Maiolino <cem@...nel.org>, Dave Chinner <david@...morbit.com>,
"Darrick J . Wong" <djwong@...nel.org>, hch <hch@....de>,
"linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, Hans Holmberg
<Hans.Holmberg@....com>
Subject: [PATCH 2/3] xfs: refactor hint based zone allocation
Replace the co-location code with a matrix that makes it more clear
on how the decisions are made.
The matrix contains scores for zone/file hint combinations. A "GOOD"
score for an open zone will result in immediate co-location while "OK"
combinations will only be picked if we cannot open a new zone.
Signed-off-by: Hans Holmberg <hans.holmberg@....com>
---
fs/xfs/xfs_zone_alloc.c | 122 ++++++++++++++++++++--------------------
1 file changed, 62 insertions(+), 60 deletions(-)
diff --git a/fs/xfs/xfs_zone_alloc.c b/fs/xfs/xfs_zone_alloc.c
index f28214c28ab5..ff24769b8870 100644
--- a/fs/xfs/xfs_zone_alloc.c
+++ b/fs/xfs/xfs_zone_alloc.c
@@ -493,64 +493,64 @@ xfs_try_open_zone(
return oz;
}
+enum xfs_zone_alloc_score {
+ /* Any open zone will do it, we're desperate */
+ XFS_ZONE_ALLOC_ANY = 0,
+
+ /* It better fit somehow */
+ XFS_ZONE_ALLOC_OK = 1,
+
+ /* Only reuse a zone if it fits really well. */
+ XFS_ZONE_ALLOC_GOOD = 2,
+};
+
/*
- * For data with short or medium lifetime, try to colocated it into an
- * already open zone with a matching temperature.
+ * Life time hint co-location matrix. Fields not set default to 0
+ * aka XFS_ZONE_ALLOC_ANY.
*/
-static bool
-xfs_colocate_eagerly(
- enum rw_hint file_hint)
-{
- switch (file_hint) {
- case WRITE_LIFE_MEDIUM:
- case WRITE_LIFE_SHORT:
- case WRITE_LIFE_NONE:
- return true;
- default:
- return false;
- }
-}
-
-static bool
-xfs_good_hint_match(
- struct xfs_open_zone *oz,
- enum rw_hint file_hint)
-{
- switch (oz->oz_write_hint) {
- case WRITE_LIFE_LONG:
- case WRITE_LIFE_EXTREME:
- /* colocate long and extreme */
- if (file_hint == WRITE_LIFE_LONG ||
- file_hint == WRITE_LIFE_EXTREME)
- return true;
- break;
- case WRITE_LIFE_MEDIUM:
- /* colocate medium with medium */
- if (file_hint == WRITE_LIFE_MEDIUM)
- return true;
- break;
- case WRITE_LIFE_SHORT:
- case WRITE_LIFE_NONE:
- case WRITE_LIFE_NOT_SET:
- /* colocate short and none */
- if (file_hint <= WRITE_LIFE_SHORT)
- return true;
- break;
- }
- return false;
-}
+static const unsigned int
+xfs_zoned_hint_score[WRITE_LIFE_HINT_NR][WRITE_LIFE_HINT_NR] = {
+ [WRITE_LIFE_NOT_SET] = {
+ [WRITE_LIFE_NOT_SET] = XFS_ZONE_ALLOC_OK,
+ [WRITE_LIFE_NONE] = XFS_ZONE_ALLOC_OK,
+ [WRITE_LIFE_SHORT] = XFS_ZONE_ALLOC_OK,
+ },
+ [WRITE_LIFE_NONE] = {
+ [WRITE_LIFE_NOT_SET] = XFS_ZONE_ALLOC_OK,
+ [WRITE_LIFE_NONE] = XFS_ZONE_ALLOC_GOOD,
+ [WRITE_LIFE_SHORT] = XFS_ZONE_ALLOC_GOOD,
+ },
+ [WRITE_LIFE_SHORT] = {
+ [WRITE_LIFE_NOT_SET] = XFS_ZONE_ALLOC_GOOD,
+ [WRITE_LIFE_NONE] = XFS_ZONE_ALLOC_GOOD,
+ [WRITE_LIFE_SHORT] = XFS_ZONE_ALLOC_GOOD,
+ },
+ [WRITE_LIFE_MEDIUM] = {
+ [WRITE_LIFE_MEDIUM] = XFS_ZONE_ALLOC_GOOD,
+ },
+ [WRITE_LIFE_LONG] = {
+ [WRITE_LIFE_LONG] = XFS_ZONE_ALLOC_OK,
+ [WRITE_LIFE_EXTREME] = XFS_ZONE_ALLOC_OK,
+ },
+ [WRITE_LIFE_EXTREME] = {
+ [WRITE_LIFE_LONG] = XFS_ZONE_ALLOC_OK,
+ [WRITE_LIFE_EXTREME] = XFS_ZONE_ALLOC_OK,
+ },
+};
static bool
xfs_try_use_zone(
struct xfs_zone_info *zi,
enum rw_hint file_hint,
struct xfs_open_zone *oz,
- bool lowspace)
+ unsigned int goodness)
{
if (oz->oz_allocated == rtg_blocks(oz->oz_rtg))
return false;
- if (!lowspace && !xfs_good_hint_match(oz, file_hint))
+
+ if (xfs_zoned_hint_score[oz->oz_write_hint][file_hint] < goodness)
return false;
+
if (!atomic_inc_not_zero(&oz->oz_ref))
return false;
@@ -581,14 +581,14 @@ static struct xfs_open_zone *
xfs_select_open_zone_lru(
struct xfs_zone_info *zi,
enum rw_hint file_hint,
- bool lowspace)
+ unsigned int goodness)
{
struct xfs_open_zone *oz;
lockdep_assert_held(&zi->zi_open_zones_lock);
list_for_each_entry(oz, &zi->zi_open_zones, oz_entry)
- if (xfs_try_use_zone(zi, file_hint, oz, lowspace))
+ if (xfs_try_use_zone(zi, file_hint, oz, goodness))
return oz;
cond_resched_lock(&zi->zi_open_zones_lock);
@@ -651,9 +651,11 @@ xfs_select_zone_nowait(
* data.
*/
spin_lock(&zi->zi_open_zones_lock);
- if (xfs_colocate_eagerly(write_hint))
- oz = xfs_select_open_zone_lru(zi, write_hint, false);
- else if (pack_tight)
+ oz = xfs_select_open_zone_lru(zi, write_hint, XFS_ZONE_ALLOC_GOOD);
+ if (oz)
+ goto out_unlock;
+
+ if (pack_tight)
oz = xfs_select_open_zone_mru(zi, write_hint);
if (oz)
goto out_unlock;
@@ -667,16 +669,16 @@ xfs_select_zone_nowait(
goto out_unlock;
/*
- * Try to colocate cold data with other cold data if we failed to open a
- * new zone for it.
+ * Try to find an zone that is an ok match to colocate data with.
+ */
+ oz = xfs_select_open_zone_lru(zi, write_hint, XFS_ZONE_ALLOC_OK);
+ if (oz)
+ goto out_unlock;
+
+ /*
+ * Pick the least recently used zone, regardless of hint match
*/
- if (write_hint != WRITE_LIFE_NOT_SET &&
- !xfs_colocate_eagerly(write_hint))
- oz = xfs_select_open_zone_lru(zi, write_hint, false);
- if (!oz)
- oz = xfs_select_open_zone_lru(zi, WRITE_LIFE_NOT_SET, false);
- if (!oz)
- oz = xfs_select_open_zone_lru(zi, WRITE_LIFE_NOT_SET, true);
+ oz = xfs_select_open_zone_lru(zi, write_hint, XFS_ZONE_ALLOC_ANY);
out_unlock:
spin_unlock(&zi->zi_open_zones_lock);
return oz;
--
2.34.1
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