Fix overlap io_u into outside regions
Test case is a job file ala this:
[global]
ioengine=posixaio
direct=0
filename=testfile
iodepth=128
size=50M
loops=10000000000
group_reporting=1
readwrite=randwrite
do_verify=1
verify=md5
verify_fatal=1
numjobs=1
thread
bsrange=4k:1M
[thread0]
offset=0G
[thread1]
offset=50M
[thread2]
offset=100M
[thread3]
offset=150M
[thread4]
offset=200M
[thread5]
offset=250M
[thread6]
offset=300M
[thread7]
offset=350M
where io_u units from threadN ends up crossing into the zone of threadN+1.
This is due to using file->real_file_size as the boundary check for the
buffer length, where the offset itself is correctly calculated. When
using mixed block sizes, this can cause a blocksize larger than the
minimum size to span into the next region.
Fix this by using file->io_size + offset as the end delimeter. Also
improve the logic of dropping to a smaller allowed block size if we do
end up being close to spanning into the next region.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/io_u.c b/io_u.c
index d35b844..51da223 100644
--- a/io_u.c
+++ b/io_u.c
@@ -341,6 +341,14 @@
return __get_next_offset(td, io_u);
}
+static inline int io_u_fits(struct thread_data *td, struct io_u *io_u,
+ unsigned int buflen)
+{
+ struct fio_file *f = io_u->file;
+
+ return io_u->offset + buflen <= f->io_size + td->o.start_offset;
+}
+
static unsigned int __get_next_buflen(struct thread_data *td, struct io_u *io_u)
{
const int ddir = io_u->ddir;
@@ -353,14 +361,15 @@
minbs = td->o.min_bs[ddir];
maxbs = td->o.max_bs[ddir];
+ if (minbs == maxbs)
+ return minbs;
+
if (td->o.use_os_rand)
rand_max = OS_RAND_MAX;
else
rand_max = FRAND_MAX;
- if (minbs == maxbs)
- buflen = minbs;
- else {
+ do {
if (td->o.use_os_rand)
r = os_random_long(&td->bsrange_state);
else
@@ -380,19 +389,16 @@
buflen = bsp->bs;
perc += bsp->perc;
- if (r <= ((rand_max / 100L) * perc))
+ if ((r <= ((rand_max / 100L) * perc)) &&
+ io_u_fits(td, io_u, buflen))
break;
}
}
+
if (!td->o.bs_unaligned && is_power_of_2(minbs))
buflen = (buflen + minbs - 1) & ~(minbs - 1);
- }
- if (io_u->offset + buflen > io_u->file->real_file_size) {
- dprint(FD_IO, "lower buflen %u -> %u (ddir=%d)\n", buflen,
- minbs, ddir);
- buflen = minbs;
- }
+ } while (!io_u_fits(td, io_u, buflen));
return buflen;
}