similar to: [RFC] Early look at btrfs directIO read code

The big problem that I have with non-directio is that buffering delays program execution. When reading/writing files that are many times larger than RAM without directio, it is very apparent that system response drops through the floor- it can take several minutes for an ssh login to prompt for a password. This is true both for UFS and ZFS. Repeat the exercise with directio on UFS and there is no

This idea is from ext4. By this patch, we can make the dio write parallel, and improve the performance. We needn''t worry about the race between dio write and truncate, because the truncate need wait untill all the dio write end. And we also needn''t worry about the race between dio write and punch hole, because we have extent lock to protect our operation. I ran fio to test the

I had to let this go and get on with testing DB2 on Solaris. I had to abandon zfs on local discs in x64 Solaris 10 5/08. The situation was that: * DB2 buffer pools occupied up to 90% of 32GB RAM on each host * DB2 cached the entire database in its buffer pools o having the file system repeat this was not helpful * running high-load DB2 tests for 2 weeks showed 100%

I noticed that if the free space cache has an error writing out it''s data it won''t actually error out, it will just carry on. This is because it doesn''t check the return value of btrfs_wait_ordered_range, which didn''t actually return anything. So fix this in order to keep us from making free space cache look valid when it really isnt. Thanks, Signed-off-by:

Hi, Does anybody know whether the ext3 file system support Direct_io? if so, how do you enable it? I went through the man page of mount, and it did not mention such option? my system is running : Red Hat Enterprise Linux AS release 3 (Taroon Update 2) Kernel 2.4.21-15.ELsmp on an i686 Thanks much!!! David. __________________________________ Do you Yahoo!? Yahoo! Mail Address

V1->V2: -Changed dio_end_io to EXPORT_SYMBOL_GPL -Removed the own_submit blockdev dio helper -Removed the boundary change V2->V3 -Made it so we keep track of what the current logical offset in the file we have a BIO setup for so we can pass it into the submit_io hook. Because BTRFS can do RAID and such, we need our own submit hook so we can setup the bio''s in the correct fashion,

Signed-off-by: Dave Kleikamp <dave.kleikamp at oracle.com> Acked-by: Joel Becker <jlbec at evilplan.org> Cc: Zach Brown <zab at zabbo.net> Cc: Mark Fasheh <mfasheh at suse.com> Cc: ocfs2-devel at oss.oracle.com --- fs/ocfs2/aops.h | 2 +- fs/ocfs2/file.c | 55 ++++++++++++++++++++++---------------------------- fs/ocfs2/ocfs2_trace.h | 6 +++--- 3 files

Hi, this is about an issue newer kernels show, bysplitting direct I/O requests into 4k pieces to directly merge them in the Block Device Layer afterwards. If anyone is interested in own tests just use a simple command like dd if=/mnt/test/test-dd1 of=/dev/null iflag=direct bs=64k count=1 in combination with blktrace. The following patch is more a proposal for discussion than a solution, well

when we fall back to buffered write from direct write, we call __generic_file_aio_write but that will end up doing direct write even we are only prepared to do buffered write because the file has O_DIRECT flag set. This is a fix for https://bugzilla.novell.com/show_bug.cgi?id=591039 revised with Joel's comments. --- fs/ocfs2/file.c | 23 ++++++++++++----------- 1 files changed, 12

From: Zach Brown <zab@zabbo.net> ocfs2''s .aio_read and .aio_write methods are changed to take iov_iter and pass it to generic functions. Wrappers are made to pack the iovecs into iters and call these new functions. Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Cc: Zach Brown <zab@zabbo.net> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker

2011/10/26 Sage Weil <sage@newdream.net>: > On Wed, 26 Oct 2011, Christian Brunner wrote: >> >> > Christian, have you tweaked those settings in your ceph.conf?  It would be >> >> > something like ''journal dio = false''.  If not, can you verify that >> >> > directio shows true when the journal is initialized from your osd log?

Hi ZFS Team, I have a couple of questions... Assume that the maximum slab size that ZFS supports is x. (I am assuming there is a maximum.) An application does a (single) write(2) for 2x bytes. Does ZFS/COW guarantee that either all the 2x bytes are persistent or none at all? Consider a case where there is a panic after x bytes has gone to disk and the change propagated to the uber block. Do

On Mon, Feb 06, 2023 at 07:00:35AM +0000, Arseniy Krasnov wrote: >This adds main logic of MSG_ZEROCOPY flag processing for packet >creation. When this flag is set and user's iov iterator fits for >zerocopy transmission, call 'get_user_pages()' and add returned >pages to the newly created skb. > >Signed-off-by: Arseniy Krasnov <AVKrasnov at sberdevices.ru>

V1->V2: Check to see if our current ppos is >= i_size after a short DIO read, just in case it was actually a short read and we need to just return. This is similar to what already happens in the write case. If we have a short read while doing O_DIRECT, instead of just returning, fallthrough and try to read the rest via buffered IO. BTRFS needs this because if we encounter a compressed or

Was there some reason that patch got dropped? Otherwise rsync eats up all the buffer memory. Note -- I tried directio -- didn't work due to alignment issues -- buffers have to be aligned to sectors. The kernel, if I remember correctly, has been on again/off again on requiring alignment on directio -- because most of the drivers and devices do for directio to work, at. "dd"

The following script is used as a first attempt to discover IO patterns in a dbase setup: #------------------------------------------------------------------ #pragma D option dynvarsize=128m dtrace:::BEGIN { } pid$target::kaio:entry { self->doit = 1; } pid$target::_aiodone:return { self->doit = 0; } io:::start /self->doit || execname == "oracle"/ {

Apparently it is ok to submit a read to an IDE device with the same target page for different offsets. This is what Windows does under qemu. The problem is under DIO we expect them to be different buffers for checksumming reasons, and so this sort of thing will result in checksum errors, when in reality the file is fine. So when reading, check to make sure that all iov bases are different, and

V1->V2: Check to see if our current ppos is >= i_size after a short DIO read, just in case it was actually a short read and we need to just return. This is similar to what already happens in the write case. If we have a short read while doing O_DIRECT, instead of just returning, fallthrough and try to read the rest via buffered IO. BTRFS needs this because if we encounter a compressed or

V1->V2: Check to see if our current ppos is >= i_size after a short DIO read, just in case it was actually a short read and we need to just return. This is similar to what already happens in the write case. If we have a short read while doing O_DIRECT, instead of just returning, fallthrough and try to read the rest via buffered IO. BTRFS needs this because if we encounter a compressed or

Hi all, I am trying to configure a failover multipath between 2 GNBD devices. I have a 4 nodes Redhat Cluster Suite (RCS) cluster. 3 of them are used for running services, 1 of them for central storage. In the future I am going to introduce another machine for central storage. The 2 storage machine are going to share/export the same disk. The idea is not to have a single point of failure