| Message ID | 1459857443-20611-9-git-send-email-tom.leiming@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Apr 05, 2016 at 07:56:53PM +0800, Ming Lei wrote: > Signed-off-by: Ming Lei <tom.leiming@gmail.com> A bit more of a commit message is always nice :) Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
The lloop driver should be removed entirely - use the loop driver instead. -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
> The lloop driver should be removed entirely - use the loop driver > instead. I talked with Andreas last week at our annual Lustre users group meeting about this. The reason I was told for existance is that some users were using files on a Lustre file system with the loop back device. The performance was really bad at the time so a lloop was developed to overcome those limitations. Its been a long time so perhaps its time to look at the default loop driver again to see if can perform now. If it doesn't we will go the route of reworking the lloop driver in the spirit of the cryptoloop device. -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sun, Apr 10, 2016 at 03:37:42PM +0100, James Simmons wrote: > > > The lloop driver should be removed entirely - use the loop driver > > instead. > > I talked with Andreas last week at our annual Lustre users group meeting > about this. The reason I was told for existance is that some users were > using files on a Lustre file system with the loop back device. The > performance was really bad at the time so a lloop was developed to > overcome those limitations. Its been a long time so perhaps its time > to look at the default loop driver again to see if can perform now. If > it doesn't we will go the route of reworking the lloop driver in the > spirit of the cryptoloop device. The loop driver now supports using AIO/DIO on any file systems that implements ->read_iter and ->write_iter. If lustre doesn't support those or doesn't have proper performance using them it should be addressed in the file system. Note that the dio mode in the loop device is not the default and you need to manually enabled it, keep that in mind when testing. -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
> On Sun, Apr 10, 2016 at 03:37:42PM +0100, James Simmons wrote: > > > > > The lloop driver should be removed entirely - use the loop driver > > > instead. > > > > I talked with Andreas last week at our annual Lustre users group meeting > > about this. The reason I was told for existance is that some users were > > using files on a Lustre file system with the loop back device. The > > performance was really bad at the time so a lloop was developed to > > overcome those limitations. Its been a long time so perhaps its time > > to look at the default loop driver again to see if can perform now. If > > it doesn't we will go the route of reworking the lloop driver in the > > spirit of the cryptoloop device. > > The loop driver now supports using AIO/DIO on any file systems that > implements ->read_iter and ->write_iter. If lustre doesn't support > those or doesn't have proper performance using them it should be > addressed in the file system. > > Note that the dio mode in the loop device is not the default and you > need to manually enabled it, keep that in mind when testing. This is excellent news. The only sad thing is that most lustre users are running distros that use kernels before the AIO/DIO enhancements were landed :-( We will have to keep a copy around for those guys. But first I need to test the performance of the loop back driver this week before this can be dropped. -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Apr 11, 2016 at 12:02 AM, James Simmons <jsimmons@infradead.org> wrote: > >> On Sun, Apr 10, 2016 at 03:37:42PM +0100, James Simmons wrote: >> > >> > > The lloop driver should be removed entirely - use the loop driver >> > > instead. >> > >> > I talked with Andreas last week at our annual Lustre users group meeting >> > about this. The reason I was told for existance is that some users were >> > using files on a Lustre file system with the loop back device. The >> > performance was really bad at the time so a lloop was developed to >> > overcome those limitations. Its been a long time so perhaps its time >> > to look at the default loop driver again to see if can perform now. If >> > it doesn't we will go the route of reworking the lloop driver in the >> > spirit of the cryptoloop device. >> >> The loop driver now supports using AIO/DIO on any file systems that >> implements ->read_iter and ->write_iter. If lustre doesn't support >> those or doesn't have proper performance using them it should be >> addressed in the file system. >> >> Note that the dio mode in the loop device is not the default and you >> need to manually enabled it, keep that in mind when testing. > > This is excellent news. The only sad thing is that most lustre users > are running distros that use kernels before the AIO/DIO enhancements > were landed :-( We will have to keep a copy around for those guys. But > first I need to test the performance of the loop back driver this > week before this can be dropped. Considered that this cleanup patch for lustre loop is quite simple and straightforward, I suggest to keep this cleanup patch as so and do the dropping in another patchset. Christoph, are you OK with that? Thanks, Ming Lei -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/staging/lustre/lustre/llite/lloop.c b/drivers/staging/lustre/lustre/llite/lloop.c index b725fc1..67323db 100644 --- a/drivers/staging/lustre/lustre/llite/lloop.c +++ b/drivers/staging/lustre/lustre/llite/lloop.c @@ -302,19 +302,20 @@ static unsigned int loop_get_bio(struct lloop_device *lo, struct bio **req) } /* TODO: need to split the bio, too bad. */ - LASSERT(first->bi_vcnt <= LLOOP_MAX_SEGMENTS); + LASSERT(bio_pages(first) <= LLOOP_MAX_SEGMENTS); rw = first->bi_rw; bio = &lo->lo_bio; while (*bio && (*bio)->bi_rw == rw) { + unsigned curr_cnt = bio_pages(*bio); CDEBUG(D_INFO, "bio sector %llu size %u count %u vcnt%u\n", (unsigned long long)(*bio)->bi_iter.bi_sector, (*bio)->bi_iter.bi_size, - page_count, (*bio)->bi_vcnt); - if (page_count + (*bio)->bi_vcnt > LLOOP_MAX_SEGMENTS) + page_count, curr_cnt); + if (page_count + curr_cnt > LLOOP_MAX_SEGMENTS) break; - page_count += (*bio)->bi_vcnt; + page_count += curr_cnt; count++; bio = &(*bio)->bi_next; }
Signed-off-by: Ming Lei <tom.leiming@gmail.com> --- drivers/staging/lustre/lustre/llite/lloop.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)