History log of /freebsd/sys/kern/kern_physio.c (Results 26 – 50 of 183)
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# 869fd29a 21-Apr-2015 Alexander Motin <mav@FreeBSD.org>

Rewrite physio() to not allocate pbufs for unmapped I/O.

pbufs is a limited resource, and their allocator is not SMP-scalable.
So instead of always allocating pbuf to immediately convert it to bio,

Rewrite physio() to not allocate pbufs for unmapped I/O.

pbufs is a limited resource, and their allocator is not SMP-scalable.
So instead of always allocating pbuf to immediately convert it to bio,
allocate bio just here. If buffer needs kernel mapping, then pbuf is
still allocated, but used only as a source of KVA and storage for a list
of held pages.

On 40-core system doing many 512-byte reads from user level to array of
raw SSDs this change removes huge lock congestion inside pbuf allocator.
It improves peak performance from ~300K to ~1.2M IOPS. On my previous
24-core system this problem also existed, but was less serious.

Reviewed by: kib
MFC after: 2 weeks

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Revision tags: release/10.1.0, release/9.3.0, release/10.0.0
# 0bfd163f 18-Oct-2013 Gleb Smirnoff <glebius@FreeBSD.org>

Merge head r233826 through r256722.


# 1ccca3b5 10-Oct-2013 Alan Somers <asomers@FreeBSD.org>

IFC @256277

Approved by: ken (mentor)


Revision tags: release/9.2.0
# ef90af83 20-Sep-2013 Peter Grehan <grehan@FreeBSD.org>

IFC @ r255692

Comment out IA32_MISC_ENABLE MSR access - this doesn't exist on AMD.
Need to sort out how arch-specific MSRs will be handled.


# d1d01586 05-Sep-2013 Simon J. Gerraty <sjg@FreeBSD.org>

Merge from head


# 46ed9e49 04-Sep-2013 Peter Grehan <grehan@FreeBSD.org>

IFC @ r255209


# f27c28dc 30-Aug-2013 Mark Murray <markm@FreeBSD.org>

MFC


# 880e57b6 29-Aug-2013 Kenneth D. Merry <ken@FreeBSD.org>

Fix some issues in change 254760 pointed out by Bruce Evans:

- Remove excessive parenthesis
- Use KNF continuation indentation
- Cut down on excessive continuation lines
- More consistent style

Fix some issues in change 254760 pointed out by Bruce Evans:

- Remove excessive parenthesis
- Use KNF continuation indentation
- Cut down on excessive continuation lines
- More consistent style in messages
- Use uprintf() instead of printf()

Submitted by: bde

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# 6871a82d 25-Aug-2013 Mark Murray <markm@FreeBSD.org>

MFC


# aaea33e5 24-Aug-2013 Kenneth D. Merry <ken@FreeBSD.org>

Fix a printf format warning on 32-bit mips and powerpc.

Reported by: bde, gjb
Pointy hat to: ken


# b2e0423c 24-Aug-2013 Mark Murray <markm@FreeBSD.org>

MFC


# 93729c17 24-Aug-2013 Kenneth D. Merry <ken@FreeBSD.org>

Add support to physio(9) for devices that don't want I/O split and
configure sa(4) to request no I/O splitting by default.

For tape devices, the user needs to be able to clearly understand
what bloc

Add support to physio(9) for devices that don't want I/O split and
configure sa(4) to request no I/O splitting by default.

For tape devices, the user needs to be able to clearly understand
what blocksize is actually being used when writing to a tape
device. The previous behavior of physio(9) was that it would split
up any I/O that was too large for the device, or too large to fit
into MAXPHYS. This means that if, for instance, the user wrote a
1MB block to a tape device, and MAXPHYS was 128KB, the 1MB write
would be split into 8 128K chunks. This would be done without
informing the user.

This has suboptimal effects, especially when trying to communicate
status to the user. In the event of an error writing to a tape
(e.g. physical end of tape) in the middle of a 1MB block that has
been split into 8 pieces, the user could have the first two 128K
pieces written successfully, the third returned with an error, and
the last 5 returned with 0 bytes written. If the user is using
a standard write(2) system call, all he will see is the ENOSPC
error. He won't have a clue how much actually got written. (With
a writev(2) system call, he should be able to determine how much
got written in addition to the error.)

The solution is to prevent physio(9) from splitting the I/O. The
new cdev flag, SI_NOSPLIT, tells physio that the driver does not
want I/O to be split beforehand.

Although the sa(4) driver now enables SI_NOSPLIT by default,
that can be disabled by two loader tunables for now. It will not
be configurable starting in FreeBSD 11.0. kern.cam.sa.allow_io_split
allows the user to configure I/O splitting for all sa(4) driver
instances. kern.cam.sa.%d.allow_io_split allows the user to
configure I/O splitting for a specific sa(4) instance.

There are also now three sa(4) driver sysctl variables that let the
users see some sa(4) driver values. kern.cam.sa.%d.allow_io_split
shows whether I/O splitting is turned on. kern.cam.sa.%d.maxio shows
the maximum I/O size allowed by kernel configuration parameters
(e.g. MAXPHYS, DFLTPHYS) and the capabilities of the controller.
kern.cam.sa.%d.cpi_maxio shows the maximum I/O size supported by
the controller.

Note that a better long term solution would be to implement support
for chaining buffers, so that that MAXPHYS is no longer a limiting
factor for I/O size to tape and disk devices. At that point, the
controller and the tape drive would become the limiting factors.

sys/conf.h: Add a new cdev flag, SI_NOSPLIT, that allows a
driver to tell physio not to split up I/O.

sys/param.h: Bump __FreeBSD_version to 1000049 for the addition
of the SI_NOSPLIT cdev flag.

kern_physio.c: If the SI_NOSPLIT flag is set on the cdev, return
any I/O that is larger than si_iosize_max or
MAXPHYS, has more than one segment, or would have
to be split because of misalignment with EFBIG.
(File too large).

In the event of an error, print a console message to
give the user a clue about what happened.

scsi_sa.c: Set the SI_NOSPLIT cdev flag on the devices created
for the sa(4) driver by default.

Add tunables to control whether we allow I/O splitting
in physio(9).

Explain in the comments that allowing I/O splitting
will be deprecated for the sa(4) driver in FreeBSD
11.0.

Add sysctl variables to display the maximum I/O
size we can do (which could be further limited by
read block limits) and the maximum I/O size that
the controller can do.

Limit our maximum I/O size (recorded in the cdev's
si_iosize_max) by MAXPHYS. This isn't strictly
necessary, because physio(9) will limit it to
MAXPHYS, but it will provide some clarity for the
application.

Record the controller's maximum I/O size reported
in the Path Inquiry CCB.

sa.4: Document the block size behavior, and explain that
the option of allowing physio(9) to split the I/O
will disappear in FreeBSD 11.0.

Sponsored by: Spectra Logic

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# ce625ec7 16-Aug-2013 Kenneth D. Merry <ken@FreeBSD.org>

Change the way that unmapped I/O capability is advertised.

The previous method was to set the D_UNMAPPED_IO flag in the cdevsw
for the driver. The problem with this is that in many cases (e.g.
sa(4

Change the way that unmapped I/O capability is advertised.

The previous method was to set the D_UNMAPPED_IO flag in the cdevsw
for the driver. The problem with this is that in many cases (e.g.
sa(4)) there may be some instances of the driver that can handle
unmapped I/O and some that can't. The isp(4) driver can handle
unmapped I/O, but the esp(4) driver currently cannot. The cdevsw
is shared among all driver instances.

So instead of setting a flag on the cdevsw, set a flag on the cdev.
This allows drivers to indicate support for unmapped I/O on a
per-instance basis.

sys/conf.h: Remove the D_UNMAPPED_IO cdevsw flag and replace it
with an SI_UNMAPPED cdev flag.

kern_physio.c: Look at the cdev SI_UNMAPPED flag to determine
whether or not a particular driver can handle
unmapped I/O.

geom_dev.c: Set the SI_UNMAPPED flag for all GEOM cdevs.
Since GEOM will create a temporary mapping when
needed, setting SI_UNMAPPED unconditionally will
work.

Remove the D_UNMAPPED_IO flag.

nvme_ns.c: Set the SI_UNMAPPED flag on cdevs created here
if NVME_UNMAPPED_BIO_SUPPORT is enabled.

vfs_aio.c: In aio_qphysio(), check the SI_UNMAPPED flag on a
cdev instead of the D_UNMAPPED_IO flag on the cdevsw.

sys/param.h: Bump __FreeBSD_version to 1000045 for the switch from
setting the D_UNMAPPED_IO flag in the cdevsw to setting
SI_UNMAPPED in the cdev.

Reviewed by: kib, jimharris
MFC after: 1 week
Sponsored by: Spectra Logic

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# 552311f4 17-Jul-2013 Xin LI <delphij@FreeBSD.org>

IFC @253398


# cfe30d02 19-Jun-2013 Gleb Smirnoff <glebius@FreeBSD.org>

Merge fresh head.


Revision tags: release/8.4.0
# 69e6d7b7 12-Apr-2013 Simon J. Gerraty <sjg@FreeBSD.org>

sync from head


# d1e99f43 27-Mar-2013 Konstantin Belousov <kib@FreeBSD.org>

Add dev_strategy_csw() function, which is similar to dev_strategy()
but assumes that a thread reference was already obtained on the passed
device. Use the function from physio(), to avoid two extra

Add dev_strategy_csw() function, which is similar to dev_strategy()
but assumes that a thread reference was already obtained on the passed
device. Use the function from physio(), to avoid two extra dev_mtx
lock and unlock. Note that physio() is always used as the cdevsw
method, or is called from a cdevsw method, and the caller already owns
the reference.

dev_strategy() is left to keep KPI intact, but now it is implemented
as a wrapper around dev_strategy_csw().

Do some style cleanup in physio().

Requested and reviewed by: kan (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks

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# 31932fae 26-Mar-2013 Alexander Kabaev <kan@FreeBSD.org>

Do not pass unmapped buffers to drivers that cannot handle them

In physio, check if device can handle unmapped IO and pass an
appropriately mapped buffer to the driver strategy routine. The
only dri

Do not pass unmapped buffers to drivers that cannot handle them

In physio, check if device can handle unmapped IO and pass an
appropriately mapped buffer to the driver strategy routine. The
only driver in the tree that can handle unmapped buffers is one
exposed by GEOM, so mark it as such with the new flag in the
driver cdevsw structure.

This fixes insta-panics on hosts, running dconschat, as /dev/fwmem
is an example of the driver that makes use of physio routine, but
bypasses the g_down thread, where the buffer gets mapped normally.

Discussed with: kib (earlier version)

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# e81ff91e 19-Mar-2013 Konstantin Belousov <kib@FreeBSD.org>

Do not remap usermode pages into KVA for physio.

Sponsored by: The FreeBSD Foundation
Tested by: pho


Revision tags: release/9.1.0, release/8.3.0_cvs, release/8.3.0, release/9.0.0, release/7.4.0_cvs, release/8.2.0_cvs, release/7.4.0, release/8.2.0
# 0c21a60c 05-Dec-2010 Marcel Moolenaar <marcel@FreeBSD.org>

svn+ssh://svn.freebsd.org/base/head@216199


# 2006fbc8 02-Dec-2010 Dimitry Andric <dim@FreeBSD.org>

Sync: merge r215944 through r216132 from ^/head.


# eea7f71c 25-Nov-2010 Konstantin Belousov <kib@FreeBSD.org>

Account i/o done on cdevs.

Reported and tested by: Adam Vande More <amvandemore gmail com>
MFC after: 1 week


Revision tags: release/8.1.0_cvs, release/8.1.0, release/7.3.0_cvs, release/7.3.0, release/8.0.0_cvs, release/8.0.0, release/7.2.0_cvs, release/7.2.0, release/7.1.0_cvs, release/7.1.0, release/6.4.0_cvs, release/6.4.0, release/7.0.0_cvs, release/7.0.0, release/6.3.0_cvs, release/6.3.0, release/6.2.0_cvs, release/6.2.0, release/5.5.0_cvs, release/5.5.0, release/6.1.0_cvs, release/6.1.0, release/6.0.0_cvs, release/6.0.0, release/5.4.0_cvs, release/5.4.0, release/4.11.0_cvs, release/4.11.0
# 9454b2d8 07-Jan-2005 Warner Losh <imp@FreeBSD.org>

/* -> /*- for copyright notices, minor format tweaks as necessary


Revision tags: release/5.3.0_cvs, release/5.3.0
# c5690651 04-Nov-2004 Poul-Henning Kamp <phk@FreeBSD.org>

Remove buf->b_dev field.


# 6afb3b1c 29-Oct-2004 Poul-Henning Kamp <phk@FreeBSD.org>

Give dev_strategy() an explict cdev argument in preparation for removing
buf->b-dev.

Put a bio between the buf passed to dev_strategy() and the device driver
strategy routine in order to not clobber

Give dev_strategy() an explict cdev argument in preparation for removing
buf->b-dev.

Put a bio between the buf passed to dev_strategy() and the device driver
strategy routine in order to not clobber fields in the buf.

Assert copyright on vfs_bio.c and update copyright message to canonical
text. There is no legal difference between John Dysons two-clause
abbreviated BSD license and the canonical text.

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