26 May, 2018
1 commit
-
No need to pass the key field to lookup_iocb to compare it with KIOCB_KEY,
as we can do that right after retrieving it from userspace. Also move the
KIOCB_KEY definition to aio.c as it is an internal value not used by any
other place in the kernel.Signed-off-by: Christoph Hellwig
02 Nov, 2017
1 commit
-
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.By default all files without license information are under the default
license of the kernel, which is GPL version 2.Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if
Reviewed-by: Philippe Ombredanne
Reviewed-by: Thomas Gleixner
Signed-off-by: Greg Kroah-Hartman
23 Dec, 2016
1 commit
-
... and fix the minor buglet in compat io_submit() - native one
kills ioctx as cleanup when put_user() fails. Get rid of
bogus compat_... in !CONFIG_AIO case, while we are at it - they
should simply fail with ENOSYS, same as for native counterparts.Signed-off-by: Al Viro
26 Mar, 2015
1 commit
-
struct kiocb now is a generic I/O container, so move it to fs.h.
Also do a #include diet for aio.h while we're at it.Signed-off-by: Christoph Hellwig
Signed-off-by: Al Viro
14 Mar, 2015
2 commits
-
Most callers in the kernel want to perform synchronous file I/O, but
still have to bloat the stack with a full struct kiocb. Split out
the parts needed in filesystem code from those in the aio code, and
only allocate those needed to pass down argument on the stack. The
aio code embedds the generic iocb in the one it allocates and can
easily get back to it by using container_of.Also add a ->ki_complete method to struct kiocb, this is used to call
into the aio code and thus removes the dependency on aio for filesystems
impementing asynchronous operations. It will also allow other callers
to substitute their own completion callback.We also add a new ->ki_flags field to work around the nasty layering
violation recently introduced in commit 5e33f6 ("usb: gadget: ffs: add
eventfd notification about ffs events").Signed-off-by: Christoph Hellwig
Signed-off-by: Al Viro -
The AIO interface is fairly complex because it tries to allow
filesystems to always work async and then wakeup a synchronous
caller through aio_complete. It turns out that basically no one
was doing this to avoid the complexity and context switches,
and we've already fixed up the remaining users and can now
get rid of this case.Signed-off-by: Christoph Hellwig
Signed-off-by: Al Viro
13 Mar, 2015
1 commit
-
There is no need to pass the total request length in the kiocb, as
we already get passed in through the iov_iter argument.Signed-off-by: Christoph Hellwig
Signed-off-by: Al Viro
30 Jul, 2013
5 commits
-
sock_aio_dtor() is dead code - and stuff that does need to do cleanup
can simply do it before calling aio_complete().Signed-off-by: Kent Overstreet
Cc: Zach Brown
Cc: Felipe Balbi
Cc: Greg Kroah-Hartman
Cc: Mark Fasheh
Cc: Joel Becker
Cc: Rusty Russell
Cc: Jens Axboe
Cc: Asai Thambi S P
Cc: Selvan Mani
Cc: Sam Bradshaw
Cc: Jeff Moyer
Cc: Al Viro
Cc: Benjamin LaHaise
Cc: Theodore Ts'o
Signed-off-by: Benjamin LaHaise -
The kiocb refcount is only needed for cancellation - to ensure a kiocb
isn't freed while a ki_cancel callback is running. But if we restrict
ki_cancel callbacks to not block (which they currently don't), we can
simply drop the refcount.Signed-off-by: Kent Overstreet
Cc: Zach Brown
Cc: Felipe Balbi
Cc: Greg Kroah-Hartman
Cc: Mark Fasheh
Cc: Joel Becker
Cc: Rusty Russell
Cc: Jens Axboe
Cc: Asai Thambi S P
Cc: Selvan Mani
Cc: Sam Bradshaw
Cc: Jeff Moyer
Cc: Al Viro
Cc: Benjamin LaHaise
Cc: Theodore Ts'o
Signed-off-by: Benjamin LaHaise -
The old aio retry infrastucture needed to save the various arguments to
to aio operations. But with the retry infrastructure gone, we can trim
struct kiocb quite a bit.Signed-off-by: Kent Overstreet
Cc: Zach Brown
Cc: Felipe Balbi
Cc: Greg Kroah-Hartman
Cc: Mark Fasheh
Cc: Joel Becker
Cc: Rusty Russell
Cc: Jens Axboe
Cc: Asai Thambi S P
Cc: Selvan Mani
Cc: Sam Bradshaw
Cc: Jeff Moyer
Cc: Al Viro
Cc: Benjamin LaHaise
Cc: Theodore Ts'o
Signed-off-by: Benjamin LaHaise -
This code doesn't serve any purpose anymore, since the aio retry
infrastructure has been removed.This change should be safe because aio_read/write are also used for
synchronous IO, and called from do_sync_read()/do_sync_write() - and
there's no looping done in the sync case (the read and write syscalls).Signed-off-by: Kent Overstreet
Cc: Zach Brown
Cc: Felipe Balbi
Cc: Greg Kroah-Hartman
Cc: Mark Fasheh
Cc: Joel Becker
Cc: Rusty Russell
Cc: Jens Axboe
Cc: Asai Thambi S P
Cc: Selvan Mani
Cc: Sam Bradshaw
Cc: Jeff Moyer
Cc: Al Viro
Cc: Benjamin LaHaise
Signed-off-by: Benjamin LaHaise -
Originally, io_event() was documented to return the io_event if
cancellation succeeded - the io_event wouldn't be delivered via the ring
buffer like it normally would.But this isn't what the implementation was actually doing; the only
driver implementing cancellation, the usb gadget code, never returned an
io_event in its cancel function. And aio_complete() was recently changed
to no longer suppress event delivery if the kiocb had been cancelled.This gets rid of the unused io_event argument to kiocb_cancel() and
kiocb->ki_cancel(), and changes io_cancel() to return -EINPROGRESS if
kiocb->ki_cancel() returned success.Also tweak the refcounting in kiocb_cancel() to make more sense.
Signed-off-by: Kent Overstreet
Cc: Zach Brown
Cc: Felipe Balbi
Cc: Greg Kroah-Hartman
Cc: Mark Fasheh
Cc: Joel Becker
Cc: Rusty Russell
Cc: Jens Axboe
Cc: Asai Thambi S P
Cc: Selvan Mani
Cc: Sam Bradshaw
Cc: Jeff Moyer
Cc: Al Viro
Cc: Benjamin LaHaise
Signed-off-by: Benjamin LaHaise
08 May, 2013
9 commits
-
Thanks to Zach Brown's work to rip out the retry infrastructure, we don't
need this anymore - ki_retry was only called right after the kiocb was
initialized.This also refactors and trims some duplicated code, as well as cleaning up
the refcounting/error handling a bit.[akpm@linux-foundation.org: use fmode_t in aio_run_iocb()]
[akpm@linux-foundation.org: fix file_start_write/file_end_write tests]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Kent Overstreet
Cc: Zach Brown
Cc: Felipe Balbi
Cc: Greg Kroah-Hartman
Cc: Mark Fasheh
Cc: Joel Becker
Cc: Rusty Russell
Cc: Jens Axboe
Cc: Asai Thambi S P
Cc: Selvan Mani
Cc: Sam Bradshaw
Cc: Jeff Moyer
Cc: Al Viro
Cc: Benjamin LaHaise
Reviewed-by: "Theodore Ts'o"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
ki_key wasn't actually used for anything previously - it was always 0.
Drop it to trim struct kiocb a bit.Signed-off-by: Kent Overstreet
Cc: Zach Brown
Cc: Felipe Balbi
Cc: Greg Kroah-Hartman
Cc: Mark Fasheh
Cc: Joel Becker
Cc: Rusty Russell
Cc: Jens Axboe
Cc: Asai Thambi S P
Cc: Selvan Mani
Cc: Sam Bradshaw
Cc: Jeff Moyer
Cc: Al Viro
Cc: Benjamin LaHaise
Reviewed-by: "Theodore Ts'o"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Previously, allocating a kiocb required touching quite a few global
(well, per kioctx) cachelines... so batching up allocation to amortize
those was worthwhile. But we've gotten rid of some of those, and in
another couple of patches kiocb allocation won't require writing to any
shared cachelines, so that means we can just rip this code out.Signed-off-by: Kent Overstreet
Cc: Zach Brown
Cc: Felipe Balbi
Cc: Greg Kroah-Hartman
Cc: Mark Fasheh
Cc: Joel Becker
Cc: Rusty Russell
Cc: Jens Axboe
Cc: Asai Thambi S P
Cc: Selvan Mani
Cc: Sam Bradshaw
Cc: Jeff Moyer
Cc: Al Viro
Cc: Benjamin LaHaise
Reviewed-by: "Theodore Ts'o"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Cancelling kiocbs requires adding them to a per kioctx linked list,
which is one of the few things we need to take the kioctx lock for in
the fast path. But most kiocbs can't be cancelled - so if we just do
this lazily, we can avoid quite a bit of locking overhead.While we're at it, instead of using a flag bit switch to using ki_cancel
itself to indicate that a kiocb has been cancelled/completed. This lets
us get rid of ki_flags entirely.[akpm@linux-foundation.org: remove buggy BUG()]
Signed-off-by: Kent Overstreet
Cc: Zach Brown
Cc: Felipe Balbi
Cc: Greg Kroah-Hartman
Cc: Mark Fasheh
Cc: Joel Becker
Cc: Rusty Russell
Cc: Jens Axboe
Cc: Asai Thambi S P
Cc: Selvan Mani
Cc: Sam Bradshaw
Cc: Jeff Moyer
Cc: Al Viro
Cc: Benjamin LaHaise
Reviewed-by: "Theodore Ts'o"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Freeing a kiocb needed to touch the kioctx for three things:
* Pull it off the reqs_active list
* Decrementing reqs_active
* Issuing a wakeup, if the kioctx was in the process of being freed.This patch moves these to aio_complete(), for a couple reasons:
* aio_complete() already has to issue the wakeup, so if we drop the
kioctx refcount before aio_complete does its wakeup we don't have to
do it twice.
* aio_complete currently has to take the kioctx lock, so it makes sense
for it to pull the kiocb off the reqs_active list too.
* A later patch is going to change reqs_active to include unreaped
completions - this will mean allocating a kiocb doesn't have to look
at the ringbuffer. So taking the decrement of reqs_active out of
kiocb_free() is useful prep work for that patch.This doesn't really affect cancellation, since existing (usb) code that
implements a cancel function still calls aio_complete() - we just have
to make sure that aio_complete does the necessary teardown for cancelled
kiocbs.It does affect code paths where we free kiocbs that were never
submitted; they need to decrement reqs_active and pull the kiocb off the
reqs_active list. This occurs in two places: kiocb_batch_free(), which
is going away in a later patch, and the error path in io_submit_one.[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Kent Overstreet
Cc: Zach Brown
Cc: Felipe Balbi
Cc: Greg Kroah-Hartman
Cc: Mark Fasheh
Cc: Joel Becker
Cc: Rusty Russell
Cc: Jens Axboe
Cc: Asai Thambi S P
Cc: Selvan Mani
Cc: Sam Bradshaw
Acked-by: Jeff Moyer
Cc: Al Viro
Cc: Benjamin LaHaise
Reviewed-by: "Theodore Ts'o"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Signed-off-by: Kent Overstreet
Cc: Zach Brown
Cc: Felipe Balbi
Cc: Greg Kroah-Hartman
Cc: Mark Fasheh
Cc: Joel Becker
Cc: Rusty Russell
Cc: Jens Axboe
Cc: Asai Thambi S P
Cc: Selvan Mani
Cc: Sam Bradshaw
Acked-by: Jeff Moyer
Cc: Al Viro
Cc: Benjamin LaHaise
Cc: Theodore Ts'o
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Nothing used the return value, and it probably wasn't possible to use it
safely for the locked versions (aio_complete(), aio_put_req()). Just
kill it.Signed-off-by: Kent Overstreet
Acked-by: Zach Brown
Cc: Felipe Balbi
Cc: Greg Kroah-Hartman
Cc: Mark Fasheh
Cc: Joel Becker
Cc: Rusty Russell
Cc: Jens Axboe
Cc: Asai Thambi S P
Cc: Selvan Mani
Cc: Sam Bradshaw
Acked-by: Jeff Moyer
Cc: Al Viro
Cc: Benjamin LaHaise
Reviewed-by: "Theodore Ts'o"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This removes the retry-based AIO infrastructure now that nothing in tree
is using it.We want to remove retry-based AIO because it is fundemantally unsafe.
It retries IO submission from a kernel thread that has only assumed the
mm of the submitting task. All other task_struct references in the IO
submission path will see the kernel thread, not the submitting task.
This design flaw means that nothing of any meaningful complexity can use
retry-based AIO.This removes all the code and data associated with the retry machinery.
The most significant benefit of this is the removal of the locking
around the unused run list in the submission path.[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Kent Overstreet
Signed-off-by: Zach Brown
Cc: Zach Brown
Cc: Felipe Balbi
Cc: Greg Kroah-Hartman
Cc: Mark Fasheh
Cc: Joel Becker
Cc: Rusty Russell
Cc: Jens Axboe
Cc: Asai Thambi S P
Cc: Selvan Mani
Cc: Sam Bradshaw
Acked-by: Jeff Moyer
Cc: Al Viro
Cc: Benjamin LaHaise
Reviewed-by: "Theodore Ts'o"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Signed-off-by: Zach Brown
Signed-off-by: Kent Overstreet
Cc: Felipe Balbi
Cc: Greg Kroah-Hartman
Cc: Mark Fasheh
Cc: Joel Becker
Cc: Rusty Russell
Cc: Jens Axboe
Cc: Asai Thambi S P
Cc: Selvan Mani
Cc: Sam Bradshaw
Acked-by: Jeff Moyer
Cc: Al Viro
Cc: Benjamin LaHaise
Reviewed-by: "Theodore Ts'o"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
31 Jul, 2012
1 commit
-
Convert init_sync_kiocb() from a nasty macro into a nice C function. The
struct assignment trick takes care of zeroing all unmentioned fields.
Shrinks fs/read_write.o's .text from 9857 bytes to 9714.Also demacroize is_sync_kiocb() and aio_ring_avail(). The latter fixes an
arg-referenced-multiple-times hand grenade.Cc: Junxiao Bi
Cc: Mark Fasheh
Acked-by: Jeff Moyer
Cc: Joel Becker
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
05 Jul, 2012
1 commit
-
Ocfs2 uses kiocb.*private as a flag of unsigned long size. In
commit a11f7e6 ocfs2: serialize unaligned aio, the unaligned
io flag is involved in it to serialize the unaligned aio. As
*private is not initialized in init_sync_kiocb() of do_sync_write(),
this unaligned io flag may be unexpectly set in an aligned dio.
And this will cause OCFS2_I(inode)->ip_unaligned_aio decreased
to -1 in ocfs2_dio_end_io(), thus the following unaligned dio
will hang forever at ocfs2_aiodio_wait() in ocfs2_file_aio_write().Signed-off-by: Junxiao Bi
Cc: stable@vger.kernel.org
Acked-by: Jeff Moyer
Signed-off-by: Joel Becker
03 Nov, 2011
1 commit
-
In testing aio on a fast storage device, I found that the context lock
takes up a fair amount of cpu time in the I/O submission path. The reason
is that we take it for every I/O submitted (see __aio_get_req). Since we
know how many I/Os are passed to io_submit, we can preallocate the kiocbs
in batches, reducing the number of times we take and release the lock.In my testing, I was able to reduce the amount of time spent in
_raw_spin_lock_irq by .56% (average of 3 runs). The command I used to
test this was:aio-stress -O -o 2 -o 3 -r 8 -d 128 -b 32 -i 32 -s 16384
I also tested the patch with various numbers of events passed to
io_submit, and I ran the xfstests aio group of tests to ensure I didn't
break anything.Signed-off-by: Jeff Moyer
Cc: Daniel Ehrenberg
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
27 Jul, 2011
1 commit
-
This allows us to move duplicated code in
(atomic_inc_not_zero() for now) toSigned-off-by: Arun Sharma
Reviewed-by: Eric Dumazet
Cc: Ingo Molnar
Cc: David Miller
Cc: Eric Dumazet
Acked-by: Mike Frysinger
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
28 May, 2010
1 commit
-
The aio compat code was not converting the struct iovecs from 32bit to
64bit pointers, causing either EINVAL to be returned from io_getevents, or
EFAULT as the result of the I/O. This patch passes a compat flag to
io_submit to signal that pointer conversion is necessary for a given iocb
array.A variant of this was tested by Michael Tokarev. I have also updated the
libaio test harness to exercise this code path with good success.
Further, I grabbed a copy of ltp and ran the
testcases/kernel/syscall/readv and writev tests there (compiled with -m32
on my 64bit system). All seems happy, but extra eyes on this would be
welcome.[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix CONFIG_COMPAT=n build]
Signed-off-by: Jeff Moyer
Reported-by: Michael Tokarev
Cc: Zach Brown
Cc: [2.6.35.1]
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
16 Dec, 2009
1 commit
-
Don't know the reason, but it appears ki_wait field of iocb never gets used.
Signed-off-by: Shaohua Li
Cc: Jeff Moyer
Cc: Benjamin LaHaise
Cc: Zach Brown
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
20 Sep, 2009
1 commit
-
fix the following 'make includecheck' warning:
include/linux/aio.h: linux/aio_abi.h is included more than once.
Signed-off-by: Jaswinder Singh Rajput
Cc: bcrl@kvack.org
Cc: Sam Ravnborg
LKML-Reference:
01 Jul, 2009
1 commit
-
Change the eventfd interface to de-couple the eventfd memory context, from
the file pointer instance.Without such change, there is no clean way to racely free handle the
POLLHUP event sent when the last instance of the file* goes away. Also,
now the internal eventfd APIs are using the eventfd context instead of the
file*.This patch is required by KVM's IRQfd code, which is still under
development.Signed-off-by: Davide Libenzi
Cc: Gregory Haskins
Cc: Rusty Russell
Cc: Benjamin LaHaise
Cc: Avi Kivity
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
29 Dec, 2008
1 commit
-
The mm->ioctx_list is currently protected by a reader-writer lock,
so we always grab that lock on the read side for doing ioctx
lookups. As the workload is extremely reader biased, turn this into
an rcu hlist so we can make lookup_ioctx() lockless. Get rid of
the rwlock and use a spinlock for providing update side exclusion.There's usually only 1 entry on this list, so it doesn't make sense
to look into fancier data structures.Reviewed-by: Jeff Moyer
Signed-off-by: Jens Axboe
17 Oct, 2008
1 commit
-
This patchs adds the CONFIG_AIO option which allows to remove support
for asynchronous I/O operations, that are not necessarly used by
applications, particularly on embedded devices. As this is a
size-reduction option, it depends on CONFIG_EMBEDDED. It allows to
save ~7 kilobytes of kernel code/data:text data bss dec hex filename
1115067 119180 217088 1451335 162547 vmlinux
1108025 119048 217088 1444161 160941 vmlinux.new
-7042 -132 0 -7174 -1C06 +/-This patch has been originally written by Matt Mackall
, and is part of the Linux Tiny project.[randy.dunlap@oracle.com: build fix]
Signed-off-by: Thomas Petazzoni
Cc: Benjamin LaHaise
Cc: Zach Brown
Signed-off-by: Matt Mackall
Signed-off-by: Randy Dunlap
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
27 Jul, 2008
1 commit
-
Removed duplicated include in include/linux/aio.h
Signed-off-by: Huang Weiyi
Signed-off-by: Benjamin LaHaise
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
29 Apr, 2008
1 commit
-
Make the following needlessly global functions static:
- __put_ioctx()
- lookup_ioctx()
- io_submit_one()Signed-off-by: Adrian Bunk
Cc: Zach Brown
Cc: Benjamin LaHaise
Cc: Badari Pulavarty
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
19 Feb, 2008
1 commit
-
Commit b2e895dbd80c420bfc0937c3729b4afe073b3848 #if 0'ed this code stating:
[PATCH] revert blockdev direct io back to 2.6.19 version
Andrew Vasquez is reporting as-iosched oopses and a 65% throughput
slowdown due to the recent special-casing of direct-io against
blockdevs. We don't know why either of these things are occurring.The patch minimally reverts us back to the 2.6.19 code for a 2.6.20
release.It has since been dead code, and unless someone wants to revive it now
it's time to remove it.This patch also makes bio_release_pages() static again and removes the
ki_bio_count member from struct kiocb, reverting changes that had been
done for this dead code.Signed-off-by: Adrian Bunk
Signed-off-by: Jens Axboe
14 Feb, 2008
1 commit
-
FASTCALL() is always expanded to empty, remove it.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Harvey Harrison
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
19 Oct, 2007
1 commit
-
Hell knows what happened in commit 63b05203af57e7de4f3bb63b8b81d43bc196d32b
during 2.6.9 development. Commit introduced io_wait field which remained
write-only than and still remains write-only.Also garbage collect macros which "use" io_wait.
Signed-off-by: Alexey Dobriyan
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
20 Jul, 2007
1 commit
-
Fix type issue reported by latest 'sparse': kiocb.ki_flags should be
"unsigned long" (not "long"), to match bitop type signature.Signed-off-by: David Brownell
Signed-off-by: Benjamin LaHaise
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
11 May, 2007
1 commit
-
This is an example about how to add eventfd support to the current KAIO code,
in order to enable KAIO to post readiness events to a pollable fd (hence
compatible with POSIX select/poll). The KAIO code simply signals the eventfd
fd when events are ready, and this triggers a POLLIN in the fd. This patch
uses a reserved for future use member of the struct iocb to pass an eventfd
file descriptor, that KAIO will use to post events every time a request
completes. At that point, an aio_getevents() will return the completed result
to a struct io_event. I made a quick test program to verify the patch, and it
runs fine here:http://www.xmailserver.org/eventfd-aio-test.c
The test program uses poll(2), but it'd, of course, work with select and epoll
too.This can allow to schedule both block I/O and other poll-able devices
requests, and wait for results using select/poll/epoll. In a typical
scenario, an application would submit KAIO request using aio_submit(), and
will also use epoll_ctl() on the whole other class of devices (that with the
addition of signals, timers and user events, now it's pretty much complete),
and then would:epoll_wait(...);
for_each_event {
if (curr_event_is_kaiofd) {
aio_getevents();
dispatch_aio_events();
} else {
dispatch_epoll_event();
}
}Signed-off-by: Davide Libenzi
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
10 May, 2007
1 commit
-
Stick an unlikely() around is_aio(): I assert that most IO is synchronous.
Cc: Suparna Bhattacharya
Cc: Ingo Molnar
Cc: Benjamin LaHaise
Cc: Zach Brown
Cc: Ulrich Drepper
Cc: Christoph Hellwig
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
14 Dec, 2006
1 commit
-
Implement block device specific .direct_IO method instead of going through
generic direct_io_worker for block device.direct_io_worker() is fairly complex because it needs to handle O_DIRECT on
file system, where it needs to perform block allocation, hole detection,
extents file on write, and tons of other corner cases. The end result is
that it takes tons of CPU time to submit an I/O.For block device, the block allocation is much simpler and a tight triple
loop can be written to iterate each iovec and each page within the iovec in
order to construct/prepare bio structure and then subsequently submit it to
the block layer. This significantly speeds up O_D on block device.[akpm@osdl.org: small speedup]
Signed-off-by: Ken Chen
Cc: Christoph Hellwig
Cc: Zach Brown
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
