| Message ID | 1407462426-6420-1-git-send-email-fdmanana@suse.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
(2014/08/08 10:47), Filipe Manana wrote: > If an inode has a very large number of extent maps, we can spend > a lot of time freeing them, which triggers a soft lockup warning. > Therefore reschedule if we need to when freeing the extent maps > while evicting the inode. > > I could trigger this all the time by running xfstests/generic/299 on > a file system with the no-holes feature enabled. That test creates > an inode with 11386677 extent maps. > > $ mkfs.btrfs -f -O no-holes $TEST_DEV > $ MKFS_OPTIONS="-O no-holes" ./check generic/299 > generic/299 382s ... > Message from syslogd@debian-vm3 at Aug 7 10:44:29 ... > kernel:[85304.208017] BUG: soft lockup - CPU#0 stuck for 22s! [umount:25330] > 384s > Ran: generic/299 > Passed all 1 tests > > $ dmesg > (...) > [86304.300017] BUG: soft lockup - CPU#0 stuck for 23s! [umount:25330] > (...) > [86304.300036] Call Trace: > [86304.300036] [<ffffffff81698ba9>] __slab_free+0x54/0x295 > [86304.300036] [<ffffffffa02ee9cc>] ? free_extent_map+0x5c/0xb0 [btrfs] > [86304.300036] [<ffffffff811a6cd2>] kmem_cache_free+0x282/0x2a0 > [86304.300036] [<ffffffffa02ee9cc>] free_extent_map+0x5c/0xb0 [btrfs] > [86304.300036] [<ffffffffa02e3775>] btrfs_evict_inode+0xd5/0x660 [btrfs] > [86304.300036] [<ffffffff811e7c8d>] ? __inode_wait_for_writeback+0x6d/0xc0 > [86304.300036] [<ffffffff816a389b>] ? _raw_spin_unlock+0x2b/0x40 > [86304.300036] [<ffffffff811d8cbb>] evict+0xab/0x180 > [86304.300036] [<ffffffff811d8dce>] dispose_list+0x3e/0x60 > [86304.300036] [<ffffffff811d9b04>] evict_inodes+0xf4/0x110 > [86304.300036] [<ffffffff811bd953>] generic_shutdown_super+0x53/0x110 > [86304.300036] [<ffffffff811bdaa6>] kill_anon_super+0x16/0x30 > [86304.300036] [<ffffffffa02a78ba>] btrfs_kill_super+0x1a/0xa0 [btrfs] > [86304.300036] [<ffffffff811bd3a9>] deactivate_locked_super+0x59/0x80 > [86304.300036] [<ffffffff811be44e>] deactivate_super+0x4e/0x70 > [86304.300036] [<ffffffff811dec14>] mntput_no_expire+0x174/0x1f0 > [86304.300036] [<ffffffff811deab7>] ? mntput_no_expire+0x17/0x1f0 > [86304.300036] [<ffffffff811e0517>] SyS_umount+0x97/0x100 > (...) > > Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com> Tested-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com> > --- > fs/btrfs/inode.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c > index 8ad3ea9..00b4bd3 100644 > --- a/fs/btrfs/inode.c > +++ b/fs/btrfs/inode.c > @@ -4718,6 +4718,11 @@ static void evict_inode_truncate_pages(struct inode *inode) > clear_bit(EXTENT_FLAG_LOGGING, &em->flags); > remove_extent_mapping(map_tree, em); > free_extent_map(em); > + if (need_resched()) { > + write_unlock(&map_tree->lock); > + cond_resched(); > + write_lock(&map_tree->lock); > + } > } > write_unlock(&map_tree->lock); > > @@ -4740,6 +4745,7 @@ static void evict_inode_truncate_pages(struct inode *inode) > &cached_state, GFP_NOFS); > free_extent_state(state); > > + cond_resched(); > spin_lock(&io_tree->lock); > } > spin_unlock(&io_tree->lock); > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" 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/fs/btrfs/inode.c b/fs/btrfs/inode.c index 8ad3ea9..00b4bd3 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -4718,6 +4718,11 @@ static void evict_inode_truncate_pages(struct inode *inode) clear_bit(EXTENT_FLAG_LOGGING, &em->flags); remove_extent_mapping(map_tree, em); free_extent_map(em); + if (need_resched()) { + write_unlock(&map_tree->lock); + cond_resched(); + write_lock(&map_tree->lock); + } } write_unlock(&map_tree->lock); @@ -4740,6 +4745,7 @@ static void evict_inode_truncate_pages(struct inode *inode) &cached_state, GFP_NOFS); free_extent_state(state); + cond_resched(); spin_lock(&io_tree->lock); } spin_unlock(&io_tree->lock);
If an inode has a very large number of extent maps, we can spend a lot of time freeing them, which triggers a soft lockup warning. Therefore reschedule if we need to when freeing the extent maps while evicting the inode. I could trigger this all the time by running xfstests/generic/299 on a file system with the no-holes feature enabled. That test creates an inode with 11386677 extent maps. $ mkfs.btrfs -f -O no-holes $TEST_DEV $ MKFS_OPTIONS="-O no-holes" ./check generic/299 generic/299 382s ... Message from syslogd@debian-vm3 at Aug 7 10:44:29 ... kernel:[85304.208017] BUG: soft lockup - CPU#0 stuck for 22s! [umount:25330] 384s Ran: generic/299 Passed all 1 tests $ dmesg (...) [86304.300017] BUG: soft lockup - CPU#0 stuck for 23s! [umount:25330] (...) [86304.300036] Call Trace: [86304.300036] [<ffffffff81698ba9>] __slab_free+0x54/0x295 [86304.300036] [<ffffffffa02ee9cc>] ? free_extent_map+0x5c/0xb0 [btrfs] [86304.300036] [<ffffffff811a6cd2>] kmem_cache_free+0x282/0x2a0 [86304.300036] [<ffffffffa02ee9cc>] free_extent_map+0x5c/0xb0 [btrfs] [86304.300036] [<ffffffffa02e3775>] btrfs_evict_inode+0xd5/0x660 [btrfs] [86304.300036] [<ffffffff811e7c8d>] ? __inode_wait_for_writeback+0x6d/0xc0 [86304.300036] [<ffffffff816a389b>] ? _raw_spin_unlock+0x2b/0x40 [86304.300036] [<ffffffff811d8cbb>] evict+0xab/0x180 [86304.300036] [<ffffffff811d8dce>] dispose_list+0x3e/0x60 [86304.300036] [<ffffffff811d9b04>] evict_inodes+0xf4/0x110 [86304.300036] [<ffffffff811bd953>] generic_shutdown_super+0x53/0x110 [86304.300036] [<ffffffff811bdaa6>] kill_anon_super+0x16/0x30 [86304.300036] [<ffffffffa02a78ba>] btrfs_kill_super+0x1a/0xa0 [btrfs] [86304.300036] [<ffffffff811bd3a9>] deactivate_locked_super+0x59/0x80 [86304.300036] [<ffffffff811be44e>] deactivate_super+0x4e/0x70 [86304.300036] [<ffffffff811dec14>] mntput_no_expire+0x174/0x1f0 [86304.300036] [<ffffffff811deab7>] ? mntput_no_expire+0x17/0x1f0 [86304.300036] [<ffffffff811e0517>] SyS_umount+0x97/0x100 (...) Signed-off-by: Filipe Manana <fdmanana@suse.com> --- fs/btrfs/inode.c | 6 ++++++ 1 file changed, 6 insertions(+)