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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@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
This commit is contained in:
Hans Holmberg 2025-09-01 10:52:05 +00:00 committed by Carlos Maiolino
parent 94deac977f
commit 0301dae732
1 changed files with 63 additions and 61 deletions
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124
fs/xfs/xfs_zone_alloc.c
View File

@ -493,64 +493,64 @@ xfs_try_open_zone(
return oz;
}
/*
* For data with short or medium lifetime, try to colocated it into an
* already open zone with a matching temperature.
*/
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;
}
}
enum xfs_zone_alloc_score {
/* Any open zone will do it, we're desperate */
XFS_ZONE_ALLOC_ANY = 0,
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;
}
/* It better fit somehow */
XFS_ZONE_ALLOC_OK = 1,
/* Only reuse a zone if it fits really well. */
XFS_ZONE_ALLOC_GOOD = 2,
};
/*
* Life time hint co-location matrix. Fields not set default to 0
* aka XFS_ZONE_ALLOC_ANY.
*/
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.
*/
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_OK);
if (oz)
goto out_unlock;
/*
* Pick the least recently used zone, regardless of hint match
*/
oz = xfs_select_open_zone_lru(zi, write_hint, XFS_ZONE_ALLOC_ANY);
out_unlock:
spin_unlock(&zi->zi_open_zones_lock);
return oz;