The dop_low field enables the low free space allocation mode when a
previous allocation has detected difficulty allocating blocks. It
has historically been part of the xfs_defer_ops structure, which
means if enabled, it remains enabled across a set of transactions
until the deferred operations have completed and the dfops is reset.
Now that the dfops is embedded in the transaction, we can save a bit
more space by using a transaction flag rather than a standalone
boolean. Drop the ->dop_low field and replace it with a transaction
flag that is set at the same points, carried across rolling
transactions and cleared on completion of deferred operations. This
essentially emulates the behavior of ->dop_low and so should not
change behavior.
Signed-off-by: Brian Foster <bfoster@xxxxxxxxxx>
---
fs/xfs/libxfs/xfs_bmap.c | 8 ++++----
fs/xfs/libxfs/xfs_bmap_btree.c | 4 ++--
fs/xfs/libxfs/xfs_defer.c | 16 ++++++++++++++--
fs/xfs/libxfs/xfs_defer.h | 11 -----------
fs/xfs/libxfs/xfs_shared.h | 12 ++++++++++++
fs/xfs/xfs_filestream.c | 3 ++-
fs/xfs/xfs_trace.h | 10 ++--------
fs/xfs/xfs_trans.h | 2 --
8 files changed, 36 insertions(+), 30 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index a85c0445b38f..8edf7522aaff 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -700,7 +700,7 @@ xfs_bmap_extents_to_btree(
if (tp->t_firstblock == NULLFSBLOCK) {
args.type = XFS_ALLOCTYPE_START_BNO;
args.fsbno = XFS_INO_TO_FSB(mp, ip->i_ino);
- } else if (tp->t_dfops->dop_low) {
+ } else if (tp->t_flags & XFS_TRANS_LOWMODE) {
args.type = XFS_ALLOCTYPE_START_BNO;
args.fsbno = tp->t_firstblock;
} else {
@@ -3449,7 +3449,7 @@ xfs_bmap_btalloc(
error = xfs_bmap_btalloc_nullfb(ap, &args, &blen);
if (error)
return error;
- } else if (ap->tp->t_dfops->dop_low) {
+ } else if (ap->tp->t_flags & XFS_TRANS_LOWMODE) {
if (xfs_inode_is_filestream(ap->ip))
args.type = XFS_ALLOCTYPE_FIRST_AG;
else
@@ -3484,7 +3484,7 @@ xfs_bmap_btalloc(
* is >= the stripe unit and the allocation offset is
* at the end of file.
*/
- if (!ap->tp->t_dfops->dop_low && ap->aeof) {
+ if (!(ap->tp->t_flags & XFS_TRANS_LOWMODE) && ap->aeof) {
if (!ap->offset) {
args.alignment = stripe_align;
atype = args.type;
@@ -3576,7 +3576,7 @@ xfs_bmap_btalloc(
args.total = ap->minlen;
if ((error = xfs_alloc_vextent(&args)))
return error;
- ap->tp->t_dfops->dop_low = true;
+ ap->tp->t_flags |= XFS_TRANS_LOWMODE;
}
if (args.fsbno != NULLFSBLOCK) {
/*
diff --git a/fs/xfs/libxfs/xfs_bmap_btree.c b/fs/xfs/libxfs/xfs_bmap_btree.c
index 01489714a253..955e29de8cae 100644
--- a/fs/xfs/libxfs/xfs_bmap_btree.c
+++ b/fs/xfs/libxfs/xfs_bmap_btree.c
@@ -226,7 +226,7 @@ xfs_bmbt_alloc_block(
* block allocation here and corrupt the filesystem.
*/
args.minleft = args.tp->t_blk_res;
- } else if (cur->bc_tp->t_dfops->dop_low) {
+ } else if (cur->bc_tp->t_flags & XFS_TRANS_LOWMODE) {
args.type = XFS_ALLOCTYPE_START_BNO;
} else {
args.type = XFS_ALLOCTYPE_NEAR_BNO;
@@ -253,7 +253,7 @@ xfs_bmbt_alloc_block(
error = xfs_alloc_vextent(&args);
if (error)
goto error0;
- cur->bc_tp->t_dfops->dop_low = true;
+ cur->bc_tp->t_flags |= XFS_TRANS_LOWMODE;
}
if (WARN_ON_ONCE(args.fsbno == NULLFSBLOCK)) {
*stat = 0;
diff --git a/fs/xfs/libxfs/xfs_defer.c b/fs/xfs/libxfs/xfs_defer.c
index e3517a53c525..0306187b5f56 100644
--- a/fs/xfs/libxfs/xfs_defer.c
+++ b/fs/xfs/libxfs/xfs_defer.c
@@ -330,9 +330,14 @@ xfs_defer_reset(
ASSERT(!xfs_defer_has_unfinished_work(dop));
- dop->dop_low = false;
memset(dop->dop_inodes, 0, sizeof(dop->dop_inodes));
memset(dop->dop_bufs, 0, sizeof(dop->dop_bufs));
+
+ /*
+ * Low mode state transfers across transaction rolls to mirror dfops
+ * lifetime. Clear it now that dfops is reset.
+ */
+ tp->t_flags &= ~XFS_TRANS_LOWMODE;
}
/*
@@ -590,7 +595,14 @@ xfs_defer_move(
memcpy(dst->dop_inodes, src->dop_inodes, sizeof(dst->dop_inodes));
memcpy(dst->dop_bufs, src->dop_bufs, sizeof(dst->dop_bufs));
- dst->dop_low = src->dop_low;
+
+ /*
+ * Low free space mode was historically controlled by a dfops field.
+ * This meant that low mode state potentially carried across multiple
+ * transaction rolls. Transfer low mode on a dfops move to preserve
+ * that behavior.
+ */
+ dtp->t_flags |= stp->t_flags & XFS_TRANS_LOWMODE;
xfs_defer_reset(stp);
}
diff --git a/fs/xfs/libxfs/xfs_defer.h b/fs/xfs/libxfs/xfs_defer.h
index d60c50498fdf..8908a2716774 100644
--- a/fs/xfs/libxfs/xfs_defer.h
+++ b/fs/xfs/libxfs/xfs_defer.h
@@ -25,17 +25,6 @@ struct xfs_defer_pending {
/*
* Header for deferred operation list.
- *
- * dop_low is used by the allocator to activate the lowspace algorithm -
- * when free space is running low the extent allocator may choose to
- * allocate an extent from an AG without leaving sufficient space for
- * a btree split when inserting the new extent. In this case the allocator
- * will enable the lowspace algorithm which is supposed to allow further
- * allocations (such as btree splits and newroots) to allocate from
- * sequential AGs. In order to avoid locking AGs out of order the lowspace
- * algorithm will start searching for free space from AG 0. If the correct
- * transaction reservations have been made then this algorithm will eventually
- * find all the space it needs.
*/
enum xfs_defer_ops_type {
XFS_DEFER_OPS_TYPE_BMAP,
diff --git a/fs/xfs/libxfs/xfs_shared.h b/fs/xfs/libxfs/xfs_shared.h
index 22089f1c880a..1c5debe748f0 100644
--- a/fs/xfs/libxfs/xfs_shared.h
+++ b/fs/xfs/libxfs/xfs_shared.h
@@ -64,6 +64,18 @@ void xfs_log_get_max_trans_res(struct xfs_mount *mp,
#define XFS_TRANS_RESERVE 0x20 /* OK to use reserved data blocks */
#define XFS_TRANS_NO_WRITECOUNT 0x40 /* do not elevate SB writecount */
#define XFS_TRANS_NOFS 0x80 /* pass KM_NOFS to kmem_alloc */
+/*
+ * LOWMODE is used by the allocator to activate the lowspace algorithm - when
+ * free space is running low the extent allocator may choose to allocate an
+ * extent from an AG without leaving sufficient space for a btree split when
+ * inserting the new extent. In this case the allocator will enable the
+ * lowspace algorithm which is supposed to allow further allocations (such as
+ * btree splits and newroots) to allocate from sequential AGs. In order to
+ * avoid locking AGs out of order the lowspace algorithm will start searching
+ * for free space from AG 0. If the correct transaction reservations have been
+ * made then this algorithm will eventually find all the space it needs.
+ */
+#define XFS_TRANS_LOWMODE 0x100 /* allocate in low space mode */
/*
* Field values for xfs_trans_mod_sb.
diff --git a/fs/xfs/xfs_filestream.c b/fs/xfs/xfs_filestream.c
index 212173c62588..182501373af2 100644
--- a/fs/xfs/xfs_filestream.c
+++ b/fs/xfs/xfs_filestream.c
@@ -20,6 +20,7 @@
#include "xfs_trace.h"
#include "xfs_ag_resv.h"
#include "xfs_trans.h"
+#include "xfs_shared.h"
struct xfs_fstrm_item {
struct xfs_mru_cache_elem mru;
@@ -378,7 +379,7 @@ xfs_filestream_new_ag(
if (xfs_alloc_is_userdata(ap->datatype))
flags |= XFS_PICK_USERDATA;
- if (ap->tp->t_dfops->dop_low)
+ if (ap->tp->t_flags & XFS_TRANS_LOWMODE)
flags |= XFS_PICK_LOWSPACE;
err = xfs_filestream_pick_ag(pip, startag, agp, flags, minlen);
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index cc6995cfce66..8807f1bb814a 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -2223,19 +2223,16 @@ DECLARE_EVENT_CLASS(xfs_defer_class,
__field(dev_t, dev)
__field(void *, dop)
__field(char, committed)
- __field(char, low)
__field(unsigned long, caller_ip)
),
TP_fast_assign(
__entry->dev = mp ? mp->m_super->s_dev : 0;
__entry->dop = dop;
- __entry->low = dop->dop_low;
__entry->caller_ip = caller_ip;
),
- TP_printk("dev %d:%d ops %p low %d, caller %pS",
+ TP_printk("dev %d:%d ops %p caller %pS",
MAJOR(__entry->dev), MINOR(__entry->dev),
__entry->dop,
- __entry->low,
(char *)__entry->caller_ip)
)
#define DEFINE_DEFER_EVENT(name) \
@@ -2251,19 +2248,16 @@ DECLARE_EVENT_CLASS(xfs_defer_error_class,
__field(dev_t, dev)
__field(void *, dop)
__field(char, committed)
- __field(char, low)
__field(int, error)
),
TP_fast_assign(
__entry->dev = mp ? mp->m_super->s_dev : 0;
__entry->dop = dop;
- __entry->low = dop->dop_low;
__entry->error = error;
),
- TP_printk("dev %d:%d ops %p low %d err %d",
+ TP_printk("dev %d:%d ops %p err %d",
MAJOR(__entry->dev), MINOR(__entry->dev),
__entry->dop,
- __entry->low,
__entry->error)
)
#define DEFINE_DEFER_ERROR_EVENT(name) \
diff --git a/fs/xfs/xfs_trans.h b/fs/xfs/xfs_trans.h
index dc79e3c1d3e8..7e493221160e 100644
--- a/fs/xfs/xfs_trans.h
+++ b/fs/xfs/xfs_trans.h
@@ -101,8 +101,6 @@ struct xfs_defer_ops {
/* relog these with each roll */
struct xfs_inode *dop_inodes[XFS_DEFER_OPS_NR_INODES];
struct xfs_buf *dop_bufs[XFS_DEFER_OPS_NR_BUFS];
-
- bool dop_low; /* alloc in low mode */
};
/*
--
2.17.1
--
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