xfs: move log discard work to xfs_discard.c

Because we are going to use the same list-based discard submission
interface for fstrim-based discards, too.

Signed-off-by: Dave Chinner <dchinner@redhat

xfs: move log discard work to xfs_discard.c

Because we are going to use the same list-based discard submission
interface for fstrim-based discards, too.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

show more ...

xfs: fix per-cpu CIL structure aggregation racing with dying cpus

In commit 7c8ade2121200 ("xfs: implement percpu cil space used
calculation"), the XFS committed (log) item list code was converted t

xfs: fix per-cpu CIL structure aggregation racing with dying cpus

In commit 7c8ade2121200 ("xfs: implement percpu cil space used
calculation"), the XFS committed (log) item list code was converted to
use per-cpu lists and space tracking to reduce cpu contention when
multiple threads are modifying different parts of the filesystem and
hence end up contending on the log structures during transaction commit.
Each CPU tracks its own commit items and space usage, and these do not
have to be merged into the main CIL until either someone wants to push
the CIL items, or we run over a soft threshold and switch to slower (but
more accurate) accounting with atomics.

Unfortunately, the for_each_cpu iteration suffers from the same race
with cpu dying problem that was identified in commit 8b57b11cca88f
("pcpcntrs: fix dying cpu summation race") -- CPUs are removed from
cpu_online_mask before the CPUHP_XFS_DEAD callback gets called. As a
result, both CIL percpu structure aggregation functions fail to collect
the items and accounted space usage at the correct point in time.

If we're lucky, the items that are collected from the online cpus exceed
the space given to those cpus, and the log immediately shuts down in
xlog_cil_insert_items due to the (apparent) log reservation overrun.
This happens periodically with generic/650, which exercises cpu hotplug
vs. the filesystem code:

smpboot: CPU 3 is now offline
XFS (sda3): ctx ticket reservation ran out. Need to up reservation
XFS (sda3): ticket reservation summary:
XFS (sda3): unit res = 9268 bytes
XFS (sda3): current res = -40 bytes
XFS (sda3): original count = 1
XFS (sda3): remaining count = 1
XFS (sda3): Filesystem has been shut down due to log error (0x2).

Applying the same sort of fix from 8b57b11cca88f to the CIL code seems
to make the generic/650 problem go away, but I've been told that tglx
was not happy when he saw:

"...the only thing we actually need to care about is that
percpu_counter_sum() iterates dying CPUs. That's trivial to do, and when
there are no CPUs dying, it has no addition overhead except for a
cpumask_or() operation."

The CPU hotplug code is rather complex and difficult to understand and I
don't want to try to understand the cpu hotplug locking well enough to
use cpu_dying mask. Furthermore, there's a performance improvement that
could be had here. Attach a private cpu mask to the CIL structure so
that we can track exactly which cpus have accessed the percpu data at
all. It doesn't matter if the cpu has since gone offline; log item
aggregation will still find the items. Better yet, we skip cpus that
have not recently logged anything.

Worse yet, Ritesh Harjani and Eric Sandeen both reported today that CPU
hot remove racing with an xfs mount can crash if the cpu_dead notifier
tries to access the log but the mount hasn't yet set up the log.

Link: https://lore.kernel.org/linux-xfs/ZOLzgBOuyWHapOyZ@dread.disaster.area/T/
Link: https://lore.kernel.org/lkml/877cuj1mt1.ffs@tglx/
Link: https://lore.kernel.org/lkml/20230414162755.281993820@linutronix.de/
Link: https://lore.kernel.org/linux-xfs/ZOVkjxWZq0YmjrJu@dread.disaster.area/T/
Cc: tglx@linutronix.de
Cc: peterz@infradead.org
Reported-by: ritesh.list@gmail.com
Reported-by: sandeen@sandeen.net
Fixes: af1c2146a50b ("xfs: introduce per-cpu CIL tracking structure")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

show more ...

xfs: xlog_sync() manually adjusts grant head space

When xlog_sync() rounds off the tail the iclog that is being
flushed, it manually subtracts that space from the grant heads. This
space is actually

xfs: xlog_sync() manually adjusts grant head space

When xlog_sync() rounds off the tail the iclog that is being
flushed, it manually subtracts that space from the grant heads. This
space is actually reserved by the transaction ticket that covers
the xlog_sync() call from xlog_write(), but we don't plumb the
ticket down far enough for it to account for the space consumed in
the current log ticket.

The grant heads are hot, so we really should be accounting this to
the ticket is we can, rather than adding thousands of extra grant
head updates every CIL commit.

Interestingly, this actually indicates a potential log space overrun
can occur when we force the log. By the time that xfs_log_force()
pushes out an active iclog and consumes the roundoff space, the
reservation for that roundoff space has been returned to the grant
heads and is no longer covered by a reservation. In theory the
roundoff added to log force on an already full log could push the
write head past the tail. In practice, the CIL commit that writes to
the log and needs the iclog pushed will have reserved space for
roundoff, so when it releases the ticket there will still be
physical space for the roundoff to be committed to the log, even
though it is no longer reserved. This roundoff won't be enough space
to allow a transaction to be woken if the log is full, so overruns
should not actually occur in practice.

That said, it indicates that we should not release the CIL context
log ticket until after we've released the commit iclog. It also
means that xlog_sync() still needs the direct grant head
manipulation if we don't provide it with a ticket. Log forces are
rare when we are in fast paths running 1.5 million transactions/s
that make the grant heads hot, so let's optimise the hot case and
pass CIL log tickets down to the xlog_sync() code.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

show more ...

xfs: avoid cil push lock if possible

Because now it hurts when the CIL fills up.

- 37.20% __xfs_trans_commit
- 35.84% xfs_log_commit_cil
- 19.34% _raw_spin_lock
- do_ra

xfs: avoid cil push lock if possible

Because now it hurts when the CIL fills up.

- 37.20% __xfs_trans_commit
- 35.84% xfs_log_commit_cil
- 19.34% _raw_spin_lock
- do_raw_spin_lock
19.01% __pv_queued_spin_lock_slowpath
- 4.20% xfs_log_ticket_ungrant
0.90% xfs_log_space_wake


Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

show more ...

xfs: move CIL ordering to the logvec chain

Adding a list_sort() call to the CIL push work while the xc_ctx_lock
is held exclusively has resulted in fairly long lock hold times and
that stops all fro

xfs: move CIL ordering to the logvec chain

Adding a list_sort() call to the CIL push work while the xc_ctx_lock
is held exclusively has resulted in fairly long lock hold times and
that stops all front end transaction commits from making progress.

We can move the sorting out of the xc_ctx_lock if we can transfer
the ordering information to the log vectors as they are detached
from the log items and then we can sort the log vectors. With these
changes, we can move the list_sort() call to just before we call
xlog_write() when we aren't holding any locks at all.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

show more ...

xfs: convert log vector chain to use list heads

Because the next change is going to require sorting log vectors, and
that requires arbitrary rearrangement of the list which cannot be
done easily wit

xfs: convert log vector chain to use list heads

Because the next change is going to require sorting log vectors, and
that requires arbitrary rearrangement of the list which cannot be
done easily with a single linked list.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

show more ...

xfs: convert CIL to unordered per cpu lists

So that we can remove the cil_lock which is a global serialisation
point. We've already got ordering sorted, so all we need to do is
treat the CIL list li

xfs: convert CIL to unordered per cpu lists

So that we can remove the cil_lock which is a global serialisation
point. We've already got ordering sorted, so all we need to do is
treat the CIL list like the busy extent list and reconstruct it
before the push starts.

This is what we're trying to avoid:

- 75.35% 1.83% [kernel] [k] xfs_log_commit_cil
- 46.35% xfs_log_commit_cil
- 41.54% _raw_spin_lock
- 67.30% do_raw_spin_lock
66.96% __pv_queued_spin_lock_slowpath

Which happens on a 32p system when running a 32-way 'rm -rf'
workload. After this patch:

- 20.90% 3.23% [kernel] [k] xfs_log_commit_cil
- 17.67% xfs_log_commit_cil
- 6.51% xfs_log_ticket_ungrant
1.40% xfs_log_space_wake
2.32% memcpy_erms
- 2.18% xfs_buf_item_committing
- 2.12% xfs_buf_item_release
- 1.03% xfs_buf_unlock
0.96% up
0.72% xfs_buf_rele
1.33% xfs_inode_item_format
1.19% down_read
0.91% up_read
0.76% xfs_buf_item_format
- 0.68% kmem_alloc_large
- 0.67% kmem_alloc
0.64% __kmalloc
0.50% xfs_buf_item_size

It kinda looks like the workload is running out of log space all
the time. But all the spinlock contention is gone and the
transaction commit rate has gone from 800k/s to 1.3M/s so the amount
of real work being done has gone up a *lot*.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

show more ...

xfs: Add order IDs to log items in CIL

Before we split the ordered CIL up into per cpu lists, we need a
mechanism to track the order of the items in the CIL. We need to do
this because there are rul

xfs: Add order IDs to log items in CIL

Before we split the ordered CIL up into per cpu lists, we need a
mechanism to track the order of the items in the CIL. We need to do
this because there are rules around the order in which related items
must physically appear in the log even inside a single checkpoint
transaction.

An example of this is intents - an intent must appear in the log
before it's intent done record so that log recovery can cancel the
intent correctly. If we have these two records misordered in the
CIL, then they will not be recovered correctly by journal replay.

We also will not be able to move items to the tail of
the CIL list when they are relogged, hence the log items will need
some mechanism to allow the correct log item order to be recreated
before we write log items to the hournal.

Hence we need to have a mechanism for recording global order of
transactions in the log items so that we can recover that order
from un-ordered per-cpu lists.

Do this with a simple monotonic increasing commit counter in the CIL
context. Each log item in the transaction gets stamped with the
current commit order ID before it is added to the CIL. If the item
is already in the CIL, leave it where it is instead of moving it to
the tail of the list and instead sort the list before we start the
push work.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

show more ...

xfs: convert CIL busy extents to per-cpu

To get them out from under the CIL lock.

This is an unordered list, so we can simply punt it to per-cpu lists
during transaction commits and reaggregate it

xfs: convert CIL busy extents to per-cpu

To get them out from under the CIL lock.

This is an unordered list, so we can simply punt it to per-cpu lists
during transaction commits and reaggregate it back into a single
list during the CIL push work.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

show more ...

xfs: track CIL ticket reservation in percpu structure

To get it out from under the cil spinlock.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

xfs: implement percpu cil space used calculation

Now that we have the CIL percpu structures in place, implement the
space used counter as a per-cpu counter.

We have to be really careful now about e

xfs: implement percpu cil space used calculation

Now that we have the CIL percpu structures in place, implement the
space used counter as a per-cpu counter.

We have to be really careful now about ensuring that the checks and
updates run without arbitrary delays, which means they need to run
with pre-emption disabled. We do this by careful placement of
the get_cpu_ptr/put_cpu_ptr calls to access the per-cpu structures
for that CPU.

We need to be able to reliably detect that the CIL has reached
the hard limit threshold so we can take extra reservations for the
iclog headers when the space used overruns the original reservation.
hence we factor out xlog_cil_over_hard_limit() from
xlog_cil_push_background().

The global CIL space used is an atomic variable that is backed by
per-cpu aggregation to minimise the number of atomic updates we do
to the global state in the fast path. While we are under the soft
limit, we aggregate only when the per-cpu aggregation is over the
proportion of the soft limit assigned to that CPU. This means that
all CPUs can use all but one byte of their aggregation threshold
and we will not go over the soft limit.

Hence once we detect that we've gone over both a per-cpu aggregation
threshold and the soft limit, we know that we have only
exceeded the soft limit by one per-cpu aggregation threshold. Even
if all CPUs hit this at the same time, we can't be over the hard
limit, so we can run an aggregation back into the atomic counter
at this point and still be under the hard limit.

At this point, we will be over the soft limit and hence we'll
aggregate into the global atomic used space directly rather than the
per-cpu counters, hence providing accurate detection of hard limit
excursion for accounting and reservation purposes.

Hence we get the best of both worlds - lockless, scalable per-cpu
fast path plus accurate, atomic detection of hard limit excursion.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

show more ...

xfs: introduce per-cpu CIL tracking structure

The CIL push lock is highly contended on larger machines, becoming a
hard bottleneck that about 700,000 transaction commits/s on >16p
machines. To addre

xfs: introduce per-cpu CIL tracking structure

The CIL push lock is highly contended on larger machines, becoming a
hard bottleneck that about 700,000 transaction commits/s on >16p
machines. To address this, start moving the CIL tracking
infrastructure to utilise per-CPU structures.

We need to track the space used, the amount of log reservation space
reserved to write the CIL, the log items in the CIL and the busy
extents that need to be completed by the CIL commit. This requires
a couple of per-cpu counters, an unordered per-cpu list and a
globally ordered per-cpu list.

Create a per-cpu structure to hold these and all the management
interfaces needed, as well as the hooks to handle hotplug CPUs.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

show more ...

xfs: rework per-iclog header CIL reservation

For every iclog that a CIL push will use up, we need to ensure we
have space reserved for the iclog header in each iclog. It is
extremely difficult to do

xfs: rework per-iclog header CIL reservation

For every iclog that a CIL push will use up, we need to ensure we
have space reserved for the iclog header in each iclog. It is
extremely difficult to do this accurately with a per-cpu counter
without expensive summing of the counter in every commit. However,
we know what the maximum CIL size is going to be because of the
hard space limit we have, and hence we know exactly how many iclogs
we are going to need to write out the CIL.

We are constrained by the requirement that small transactions only
have reservation space for a single iclog header built into them.
At commit time we don't know how much of the current transaction
reservation is made up of iclog header reservations as calculated by
xfs_log_calc_unit_res() when the ticket was reserved. As larger
reservations have multiple header spaces reserved, we can steal
more than one iclog header reservation at a time, but we only steal
the exact number needed for the given log vector size delta.

As a result, we don't know exactly when we are going to steal iclog
header reservations, nor do we know exactly how many we are going to
need for a given CIL.

To make things simple, start by calculating the worst case number of
iclog headers a full CIL push will require. Record this into an
atomic variable in the CIL. Then add a byte counter to the log
ticket that records exactly how much iclog header space has been
reserved in this ticket by xfs_log_calc_unit_res(). This tells us
exactly how much space we can steal from the ticket at transaction
commit time.

Now, at transaction commit time, we can check if the CIL has a full
iclog header reservation and, if not, steal the entire reservation
the current ticket holds for iclog headers. This minimises the
number of times we need to do atomic operations in the fast path,
but still guarantees we get all the reservations we need.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

show more ...

xfs: lift init CIL reservation out of xc_cil_lock

The xc_cil_lock is the most highly contended lock in XFS now. To
start the process of getting rid of it, lift the initial reservation
of the CIL log

xfs: lift init CIL reservation out of xc_cil_lock

The xc_cil_lock is the most highly contended lock in XFS now. To
start the process of getting rid of it, lift the initial reservation
of the CIL log space out from under the xc_cil_lock.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

show more ...

xfs: use the CIL space used counter for emptiness checks

In the next patches we are going to make the CIL list itself
per-cpu, and so we cannot use list_empty() to check is the list is
empty. Replac

xfs: use the CIL space used counter for emptiness checks

In the next patches we are going to make the CIL list itself
per-cpu, and so we cannot use list_empty() to check is the list is
empty. Replace the list_empty() checks with a flag in the CIL to
indicate we have committed at least one transaction to the CIL and
hence the CIL is not empty.

We need this flag to be an atomic so that we can clear it without
holding any locks in the commit fast path, but we also need to be
careful to avoid atomic operations in the fast path. Hence we use
the fact that test_bit() is not an atomic op to first check if the
flag is set and then run the atomic test_and_clear_bit() operation
to clear it and steal the initial unit reservation for the CIL
context checkpoint.

When we are switching to a new context in a push, we place the
setting of the XLOG_CIL_EMPTY flag under the xc_push_lock. THis
allows all the other places that need to check whether the CIL is
empty to use test_bit() and still be serialised correctly with the
CIL context swaps that set the bit.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

show more ...

xfs: can't use kmem_zalloc() for attribute buffers

Because heap allocation of 64kB buffers will fail:

....
XFS: fs_mark(8414) possible memory allocation deadlock size 65768 in kmem_alloc (mode:0x2

xfs: can't use kmem_zalloc() for attribute buffers

Because heap allocation of 64kB buffers will fail:

....
XFS: fs_mark(8414) possible memory allocation deadlock size 65768 in kmem_alloc (mode:0x2d40)
XFS: fs_mark(8417) possible memory allocation deadlock size 65768 in kmem_alloc (mode:0x2d40)
XFS: fs_mark(8409) possible memory allocation deadlock size 65768 in kmem_alloc (mode:0x2d40)
XFS: fs_mark(8428) possible memory allocation deadlock size 65768 in kmem_alloc (mode:0x2d40)
XFS: fs_mark(8430) possible memory allocation deadlock size 65768 in kmem_alloc (mode:0x2d40)
XFS: fs_mark(8437) possible memory allocation deadlock size 65768 in kmem_alloc (mode:0x2d40)
XFS: fs_mark(8433) possible memory allocation deadlock size 65768 in kmem_alloc (mode:0x2d40)
XFS: fs_mark(8406) possible memory allocation deadlock size 65768 in kmem_alloc (mode:0x2d40)
XFS: fs_mark(8412) possible memory allocation deadlock size 65768 in kmem_alloc (mode:0x2d40)
XFS: fs_mark(8432) possible memory allocation deadlock size 65768 in kmem_alloc (mode:0x2d40)
XFS: fs_mark(8424) possible memory allocation deadlock size 65768 in kmem_alloc (mode:0x2d40)
....

I'd use kvmalloc() instead, but....

- 48.19% xfs_attr_create_intent
- 46.89% xfs_attri_init
- kvmalloc_node
- 46.04% __kmalloc_node
- kmalloc_large_node
- 45.99% __alloc_pages
- 39.39% __alloc_pages_slowpath.constprop.0
- 38.89% __alloc_pages_direct_compact
- 38.71% try_to_compact_pages
- compact_zone_order
- compact_zone
- 21.09% isolate_migratepages_block
10.31% PageHuge
5.82% set_pfnblock_flags_mask
0.86% get_pfnblock_flags_mask
- 4.48% __reset_isolation_suitable
4.44% __reset_isolation_pfn
- 3.56% __pageblock_pfn_to_page
1.33% pfn_to_online_page
2.83% get_pfnblock_flags_mask
- 0.87% migrate_pages
0.86% compaction_alloc
0.84% find_suitable_fallback
- 6.60% get_page_from_freelist
4.99% clear_page_erms
- 1.19% _raw_spin_lock_irqsave
- do_raw_spin_lock
__pv_queued_spin_lock_slowpath
- 0.86% __vmalloc_node_range
0.65% __alloc_pages_bulk

.... this is just yet another reminder of how much kvmalloc() sucks.
So lift xlog_cil_kvmalloc(), rename it to xlog_kvmalloc() and use
that instead....

We also clean up the attribute name and value lengths as they no
longer need to be rounded out to sizes compatible with log vectors.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

show more ...

xfs: intent item whiteouts

When we log modifications based on intents, we add both intent
and intent done items to the modification being made. These get
written to the log to ensure that the operat

xfs: intent item whiteouts

When we log modifications based on intents, we add both intent
and intent done items to the modification being made. These get
written to the log to ensure that the operation is re-run if the
intent done is not found in the log.

However, for operations that complete wholly within a single
checkpoint, the change in the checkpoint is atomic and will never
need replay. In this case, we don't need to actually write the
intent and intent done items to the journal because log recovery
will never need to manually restart this modification.

Log recovery currently handles intent/intent done matching by
inserting the intent into the AIL, then removing it when a matching
intent done item is found. Hence for all the intent-based operations
that complete within a checkpoint, we spend all that time parsing
the intent/intent done items just to cancel them and do nothing with
them.

Hence it follows that the only time we actually need intents in the
log is when the modification crosses checkpoint boundaries in the
log and so may only be partially complete in the journal. Hence if
we commit and intent done item to the CIL and the intent item is in
the same checkpoint, we don't actually have to write them to the
journal because log recovery will always cancel the intents.

We've never really worried about the overhead of logging intents
unnecessarily like this because the intents we log are generally
very much smaller than the change being made. e.g. freeing an extent
involves modifying at lease two freespace btree blocks and the AGF,
so the EFI/EFD overhead is only a small increase in space and
processing time compared to the overall cost of freeing an extent.

However, delayed attributes change this cost equation dramatically,
especially for inline attributes. In the case of adding an inline
attribute, we only log the inode core and attribute fork at present.
With delayed attributes, we now log the attr intent which includes
the name and value, the inode core adn attr fork, and finally the
attr intent done item. We increase the number of items we log from 1
to 3, and the number of log vectors (regions) goes up from 3 to 7.
Hence we tripple the number of objects that the CIL has to process,
and more than double the number of log vectors that need to be
written to the journal.

At scale, this means delayed attributes cause a non-pipelined CIL to
become CPU bound processing all the extra items, resulting in a > 40%
performance degradation on 16-way file+xattr create worklaods.
Pipelining the CIL (as per 5.15) reduces the performance degradation
to 20%, but now the limitation is the rate at which the log items
can be written to the iclogs and iclogs be dispatched for IO and
completed.

Even log IO completion is slowed down by these intents, because it
now has to process 3x the number of items in the checkpoint.
Processing completed intents is especially inefficient here, because
we first insert the intent into the AIL, then remove it from the AIL
when the intent done is processed. IOWs, we are also doing expensive
operations in log IO completion we could completely avoid if we
didn't log completed intent/intent done pairs.

Enter log item whiteouts.

When an intent done is committed, we can check to see if the
associated intent is in the same checkpoint as we are currently
committing the intent done to. If so, we can mark the intent log
item with a whiteout and immediately free the intent done item
rather than committing it to the CIL. We can basically skip the
entire formatting and CIL insertion steps for the intent done item.

However, we cannot remove the intent item from the CIL at this point
because the unlocked per-cpu CIL item lists do not permit removal
without holding the CIL context lock exclusively. Transaction commit
only holds the context lock shared, hence the best we can do is mark
the intent item with a whiteout so that the CIL push can release it
rather than writing it to the log.

This means we never write the intent to the log if the intent done
has also been committed to the same checkpoint, but we'll always
write the intent if the intent done has not been committed or has
been committed to a different checkpoint. This will result in
correct log recovery behaviour in all cases, without the overhead of
logging unnecessary intents.

This intent whiteout concept is generic - we can apply it to all
intent/intent done pairs that have a direct 1:1 relationship. The
way deferred ops iterate and relog intents mean that all intents
currently have a 1:1 relationship with their done intent, and hence
we can apply this cancellation to all existing intent/intent done
implementations.

For delayed attributes with a 16-way 64kB xattr create workload,
whiteouts reduce the amount of journalled metadata from ~2.5GB/s
down to ~600MB/s and improve the creation rate from 9000/s to
14000/s.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

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xfs: factor and move some code in xfs_log_cil.c

In preparation for adding support for intent item whiteouts.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@k

xfs: factor and move some code in xfs_log_cil.c

In preparation for adding support for intent item whiteouts.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

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xfs: CIL context doesn't need to count iovecs

Now that we account for log opheaders in the log item formatting
code, we don't actually use the aggregated count of log iovecs in
the CIL for anything.

xfs: CIL context doesn't need to count iovecs

Now that we account for log opheaders in the log item formatting
code, we don't actually use the aggregated count of log iovecs in
the CIL for anything. Remove it and the tracking code that
calculates it.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

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xfs: xlog_write() doesn't need optype anymore

So remove it from the interface and callers.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewe

xfs: xlog_write() doesn't need optype anymore

So remove it from the interface and callers.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

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xfs: pass lv chain length into xlog_write()

The caller of xlog_write() usually has a close accounting of the
aggregated vector length contained in the log vector chain passed to
xlog_write(). There

xfs: pass lv chain length into xlog_write()

The caller of xlog_write() usually has a close accounting of the
aggregated vector length contained in the log vector chain passed to
xlog_write(). There is no need to iterate the chain to calculate he
length of the data in xlog_write_calculate_len() if the caller is
already iterating that chain to build it.

Passing in the vector length avoids doing an extra chain iteration,
which can be a significant amount of work given that large CIL
commits can have hundreds of thousands of vectors attached to the
chain.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

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xfs: reserve space and initialise xlog_op_header in item formatting

Current xlog_write() adds op headers to the log manually for every
log item region that is in the vector passed to it. While
xlog_

xfs: reserve space and initialise xlog_op_header in item formatting

Current xlog_write() adds op headers to the log manually for every
log item region that is in the vector passed to it. While
xlog_write() needs to stamp the transaction ID into the ophdr, we
already know it's length, flags, clientid, etc at CIL commit time.

This means the only time that xlog write really needs to format and
reserve space for a new ophdr is when a region is split across two
iclogs. Adding the opheader and accounting for it as part of the
normal formatted item region means we simplify the accounting
of space used by a transaction and we don't have to special case
reserving of space in for the ophdrs in xlog_write(). It also means
we can largely initialise the ophdr in transaction commit instead
of xlog_write, making the xlog_write formatting inner loop much
tighter.

xlog_prepare_iovec() is now too large to stay as an inline function,
so we move it out of line and into xfs_log.c.

Object sizes:
text data bss dec hex filename
1125934 305951 484 1432369 15db31 fs/xfs/built-in.a.before
1123360 305951 484 1429795 15d123 fs/xfs/built-in.a.after

So the code is a roughly 2.5kB smaller with xlog_prepare_iovec() now
out of line, even though it grew in size itself.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

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xfs: log tickets don't need log client id

We currently set the log ticket client ID when we reserve a
transaction. This client ID is only ever written to the log by
a CIL checkpoint or unmount recor

xfs: log tickets don't need log client id

We currently set the log ticket client ID when we reserve a
transaction. This client ID is only ever written to the log by
a CIL checkpoint or unmount records, and so anything using a high
level transaction allocated through xfs_trans_alloc() does not need
a log ticket client ID to be set.

For the CIL checkpoint, the client ID written to the journal is
always XFS_TRANSACTION, and for the unmount record it is always
XFS_LOG, and nothing else writes to the log. All of these operations
tell xlog_write() exactly what they need to write to the log (the
optype) and build their own opheaders for start, commit and unmount
records. Hence we no longer need to set the client id in either the
log ticket or the xfs_trans.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

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xfs: embed the xlog_op_header in the commit record

Remove the final case where xlog_write() has to prepend an opheader
to a log transaction. Similar to the start record, the commit record
is just an

xfs: embed the xlog_op_header in the commit record

Remove the final case where xlog_write() has to prepend an opheader
to a log transaction. Similar to the start record, the commit record
is just an empty opheader with a XLOG_COMMIT_TRANS type, so we can
just make this the payload for the region being passed to
xlog_write() and remove the special handling in xlog_write() for
the commit record.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

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xfs: only CIL pushes require a start record

So move the one-off start record writing in xlog_write() out into
the static header that the CIL push builds to write into the log
initially. This simplif

xfs: only CIL pushes require a start record

So move the one-off start record writing in xlog_write() out into
the static header that the CIL push builds to write into the log
initially. This simplifes the xlog_write() logic a lot.

pahole on x86-64 confirms that the xlog_cil_trans_hdr is correctly
32 bit aligned and packed for copying the log op and transaction
headers directly into the log as a single log region copy.

struct xlog_cil_trans_hdr {
struct xlog_op_header oph[2]; /* 0 24 */
struct xfs_trans_header thdr; /* 24 16 */
struct xfs_log_iovec lhdr[2]; /* 40 32 */

/* size: 72, cachelines: 2, members: 3 */
/* last cacheline: 8 bytes */
};

A wart is needed to handle the fact that length of the region the
opheader points to doesn't include the opheader length. hence if
we embed the opheader, we have to substract the opheader length from
the length written into the opheader by the generic copying code.
This will eventually go away when everything is converted to
embedded opheaders.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

show more ...