completely understand], md_takeroot() runs before md_preloaded(),
rendering both useless.
As a fix, move the body (effectively one line!) of md_takeroot()
into md_preloaded(), and get rid of the stuff that has become useless.
Bug and fix reported 10 days ago on -current, no reply.
mappings required by mdstart_swap(). On i386, if the ephemeral mapping
is already in the sf_buf mapping cache, a swap-backed md performs
similarly to a malloc-backed md. Even if the ephemeral mapping is not
cached, this implementation is still faster. On 64-bit platforms, this
change has the effect of using the direct virtual-to-physical mapping,
avoiding ephemeral mapping overheads, such as TLB shootdowns on SMPs.
On a 2.4GHz, 400MHz FSB P4 Xeon configured with 64K sf_bufs and
"mdmfs -S -o async -s 128m md /mnt"
before:
dd if=/dev/md0 of=/dev/null bs=64k
134217728 bytes transferred in 0.430923 secs (311465697 bytes/sec)
after with cold sf_buf cache:
dd if=/dev/md0 of=/dev/null bs=64k
134217728 bytes transferred in 0.367948 secs (364773576 bytes/sec)
after with warm sf_buf cache:
dd if=/dev/md0 of=/dev/null bs=64k
134217728 bytes transferred in 0.252826 secs (530870010 bytes/sec)
malloc-backed md:
dd if=/dev/md0 of=/dev/null bs=64k
134217728 bytes transferred in 0.253126 secs (530240978 bytes/sec)
On vnode backed md(4) devices over a certain, currently undetermined
size relative to the buffer cache our "lemming-syncer" can provoke
a buffer starvation which puts the md thread to sleep on wdrain.
This generally tends to grind the entire system to a stop because the
event that is supposed to wake up the thread will not happen until a fair
bit of the piled up I/O requests in the system finish, and since a lot
of those are on a md(4) vnode backed device which is currently waiting
on wdrain until a fair amount of the piled up ... you get the picture.
The cure is to issue all VOP_WRITES on the vnode backing the device
with IO_SYNC.
In addition to more closely emulating a real disk device with a
non-lying write-cache, this makes the writes exempt from rate-limited
(there to avoid starving the buffer cache) and consequently prevents
the deadlock.
Unfortunately performance takes a hit.
Add "async" option to give people who know what they are doing the
old behaviour.
swap-backed memory disks. This reduces filesystem allocation overhead
and makes swap-backed memory disks compatible with broken code (dd,
for example) which expects to see 512 byte sectors. The size of a
swap-backed memory disk must still be a multiple of the page size.
When performing page-aligned operations, this change has zero
performance impact.
Reviewed by: phk
Approved by: rwatson (mentor)
Introduce d_version field in struct cdevsw, this must always be
initialized to D_VERSION.
Flip sense of D_NOGIANT flag to D_NEEDGIANT, this involves removing
four D_NOGIANT flags and adding 145 D_NEEDGIANT flags.
the "old" SYSINIT. This makes sure things happen in the right order.
XXX: md(4) needs to be fully geom-ified and in particluar /dev/md.ctl
should be abandonded for the GEOM OaM api.
Approved by: re@
provide no methods does not make any sense, and is not used by any
driver.
It is a pretty hard to come up with even a theoretical concept of
a device driver which would always fail open and close with ENODEV.
Change the defaults to be nullopen() and nullclose() which simply
does nothing.
Remove explicit initializations to these from the drivers which
already used them.
Retain the mistake of not updating the devstat API for now.
Spell bioq_disksort() consistently with the remaining bioq_*().
#include <geom/geom_disk.h> where this is more appropriate.
in geom_disk.c.
As a side effect this makes a lot of #include <sys/devicestat.h>
lines not needed and some biofinish() calls can be reduced to
biodone() again.
branches:
Initialize struct cdevsw using C99 sparse initializtion and remove
all initializations to default values.
This patch is automatically generated and has been tested by compiling
LINT with all the fields in struct cdevsw in reverse order on alpha,
sparc64 and i386.
Approved by: re(scottl)
devices.
We use the md_pad[] array and if there are more units than its size the
last returned unit number will be -1, but the number of units returned
is correct.
Only grab giant in the per unit kthread for SWAP and VNODE backed devices.
Initialize the bioq before the kthread gets a chance to study it.
Don't lock Giant in mddone_swap, we shouldn't need it.
inconsistent when we do not do it for swap or vnode.
We still printf for preloaded disks because of the weak debugging
options people have in embedded/tiny environments where this is
usually used.
in the per-device kthread. This ensures that synchronisation with
mddestroy() succeeds even if the kthread was not waiting in tsleep()
at the time of the wakeup(). Among other things, this fixes the
problem of mdconfig getting stuck when an attempt is made to use a
zero-length file as a vnode-type backing store.
Approved by: re
doesn't give them enough stack to do much before blowing away the pcb.
This adds MI and MD code to allow the allocation of an alternate kstack
who's size can be speficied when calling kthread_create. Passing the
value 0 prevents the alternate kstack from being created. Note that the
ia64 MD code is missing for now, and PowerPC was only partially written
due to the pmap.c being incomplete there.
Though this patch does not modify anything to make use of the alternate
kstack, acpi and usb are good candidates.
Reviewed by: jake, peter, jhb
and predictable way, and I apologize if I have gotten it wrong anywhere,
getting prior review on a patch like this is not feasible, considering
the number of people involved and hardware availability etc.)
If struct disklabel is the messenger: kill the messenger.
Inside struct disk we had a struct disklabel which disk drivers used to
communicate certain metrics to the disklayer above (GEOM or the disk
mini-layer). This commit changes this communication to use four
explicit fields instead.
Amongst the benefits is that the fields do not get overwritten by
wrong or bogus on-disk disklabels.
Once that is clear, <sys/disk.h> which is included in the drivers
no longer need to pull <sys/disklabel.h> and <sys/diskslice.h> in,
the few places that needs them, have gotten explicit #includes for
them.
The disklabel inside struct disk is now only for internal use in
the disk mini-layer, so instead of embedding it, we malloc it as
we need it.
This concludes (modulus any mistakes) the series of disklabel related
commits.
I belive it all amounts to a NOP for all the rest of you :-)
Sponsored by: DARPA & NAI Labs.
remove the need for a contiguous array with pointers to all the sectors.
Try to make failure to malloc(9) memory a non-hang situation.
Eventually this will allow us to test the 64bit cleanness of the disk
I/O patch, but more work is outstanding here and elsewhere.
Sponsored by: DARPA & NAI Labs.
the bio and buffer structures to have daddr64_t bio_pblkno,
b_blkno, and b_lblkno fields which allows access to disks
larger than a Terabyte in size. This change also requires
that the VOP_BMAP vnode operation accept and return daddr64_t
blocks. This delta should not affect system operation in
any way. It merely sets up the necessary interfaces to allow
the development of disk drivers that work with these larger
disk block addresses. It also allows for the development of
UFS2 which will use 64-bit block addresses.
in wdrain during a write. This flag needs to be used in devices whos
strategy routines turn-around and issue another high level I/O, such as
when MD turns around and issues a VOP_WRITE to vnode backing store, in order
to avoid deadlocking the dirty buffer draining code.
Remove a vprintf() warning from MD when the backing vnode is found to be
in-use. The syncer of buf_daemon could be flushing the backing vnode at
the time of an MD operation so the warning is not correct.
MFC after: 1 week
- crhold() returns a reference to the ucred whose refcount it bumps.
- crcopy() now simply copies the credentials from one credential to
another and has no return value.
- a new crshared() primitive is added which returns true if a ucred's
refcount is > 1 and false (0) otherwise.
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.
Sorry john! (your next MFC will be a doosie!)
Reviewed by: peter@freebsd.org, dillon@freebsd.org
X-MFC after: ha ha ha ha
I already deleted it some time ago). This should fix problem people have with
unsefined reference to `MD_PRELOAD_COMPRESSED'.
Submitted by: Manfred Antar <null@pozo.com>
if all disks were detached sucessfully;
- use consistent style for return statements and fix several others style
inconsistencies.
Reviewed by: ru
Approved by: phk
bypass some extra anti-foot-shooting measures. Currently, its only
effect is to allow detaching a device while it's still open (e.g.,
mounted). This is useful for testing how the system reacts to a disk
suddenly going away, which can happen with some removeable media.
At this point, the force option is only checked on detach, so it
would've been possible to allow the option to be passed with the
MDIOCDETACH operation. This was not done to allow the possibility of
having the force flag influence other tests in the future, which may
not necessarily deal with detaching the device.
Reviewed by: sobomax
Approved by: phk
to hang or panic kernel by detaching disk from which fs is mounted;
- replace "md" with MD_NAME in yet another place.
Reviewed by: phk
Approved by: phk
(this commit is just the first stage). Also add various GIANT_ macros to
formalize the removal of Giant, making it easy to test in a more piecemeal
fashion. These macros will allow us to test fine-grained locks to a degree
before removing Giant, and also after, and to remove Giant in a piecemeal
fashion via sysctl's on those subsystems which the authors believe can
operate without Giant.
vm_mtx does not recurse and is required for most low level
vm operations.
faults can not be taken without holding Giant.
Memory subsystems can now call the base page allocators safely.
Almost all atomic ops were removed as they are covered under the
vm mutex.
Alpha and ia64 now need to catch up to i386's trap handlers.
FFS and NFS have been tested, other filesystems will need minor
changes (grabbing the vm lock when twiddling page properties).
Reviewed (partially) by: jake, jhb
other "system" header files.
Also help the deprecation of lockmgr.h by making it a sub-include of
sys/lock.h and removing sys/lockmgr.h form kernel .c files.
Sort sys/*.h includes where possible in affected files.
OK'ed by: bde (with reservations)
