Re: ceph-fuse segfaults ( jewel 10.2.2)

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Fri, Jul 15, 2016 at 11:19:12AM +0800, Yan, Zheng wrote:
> On Fri, Jul 15, 2016 at 9:35 AM, Goncalo Borges
> <goncalo.borges@xxxxxxxxxxxxx> wrote:
> > So, we are hopping that compiling 10.2.2 in an intel processor without the
> > AVX extensions will solve our problem.
> >
> > Does this make sense?
> 
> I have a different theory. ObjectCacher::flush() checks
> "bh->last_write <= cutoff" to decide if it should write buffer head.
> But ObjectCacher::bh_write_adjacencies() checks "bh->last_write <
> cutoff". (cutoff is the time clock when ObjectCacher::flush() starts
> executing). If there is only one dirty buffer head and its last_write
> is equal to cutoff, the segfault happens. For some hardware
> limitations, AMD 62xx CPU may unable to provide high precision time
> clock. This explains the segfault only happens in AMD 62xx. The code
> that causes the segfault was introduced in jewel release. So ceph-fuse
> 9.2.0 does not have this problem.

Hmmm... this also make a lot of sense.

I guess trying with your patch on all the CPUs mentioned should prove it one
way or the other.

-- 
Cheers,
Brad

> 
> 
> Regards
> Yan, Zheng
> 
> 
> 
> 
> >
> > The compilation takes a while but I will update the issue once I have
> > finished this last experiment (in the next few days)
> >
> > Cheers
> > Goncalo
> >
> >
> >
> > On 07/12/2016 09:45 PM, Goncalo Borges wrote:
> >
> > Hi All...
> >
> > Thank you for continuing to follow this already very long thread.
> >
> > Pat and Greg are correct in their assumption regarding the 10gb virtual
> > memory footprint I see for ceph-fuse process in our cluster with 12 core (24
> > because of hyperthreading) machines and 96 gb of RAM. The source is glibc >
> > 1.10. I can reduce / tune virtual memory threads usage by setting
> > MALLOC_ARENA_MAX = 4 (the default is 8 on 64 bits machines) before mounting
> > the filesystem with ceph-fuse. So, there is no memory leak on ceph-fuse :-)
> >
> > The bad news is that, while reading the arena malloc glibc explanation, it
> > became obvious that the virtual memory footprint scales with tje numer of
> > cores. Therefore the 10gb virtual memory i was seeing in the resources with
> > 12 cores (24 because of hyperthreading) could not / would not be the same in
> > the VMs where I get the segfault since they have only 4 cores.
> >
> > So, at this point, I know that:
> > a./ The segfault is always appearing in a set of VMs with 16 GB of RAM and 4
> > cores.
> > b./ The segfault is not appearing in a set of VMs (in principle identical to
> > the 16 GB ones) but with 16 cores and 64 GB of RAM.
> > c./ the segfault is not appearing in a physicall cluster with machines with
> > 96 GB of RAM and 12 cores (24 because of hyperthreading)
> > and I am not so sure anymore that this is memory related.
> >
> > For further debugging, I've updated
> >    http://tracker.ceph.com/issues/16610
> > with a summary of my finding plus some log files:
> >   - The gdb.txt I get after running
> >   $ gdb /path/to/ceph-fuse core.XXXX
> >   (gdb) set pag off
> >   (gdb) set log on
> >   (gdb) thread apply all bt
> >   (gdb) thread apply all bt full
> >   as advised by Brad
> > - The debug.out (gzipped) I get after running ceph-fuse in debug mode with
> > 'debug client 20' and 'debug objectcacher = 20'
> >
> > Cheers
> > Goncalo
> > ________________________________________
> > From: Gregory Farnum [gfarnum@xxxxxxxxxx]
> > Sent: 12 July 2016 03:07
> > To: Goncalo Borges
> > Cc: John Spray; ceph-users
> > Subject: Re:  ceph-fuse segfaults ( jewel 10.2.2)
> >
> > Oh, is this one of your custom-built packages? Are they using
> > tcmalloc? That difference between VSZ and RSS looks like a glibc
> > malloc problem.
> > -Greg
> >
> > On Mon, Jul 11, 2016 at 12:04 AM, Goncalo Borges
> > <goncalo.borges@xxxxxxxxxxxxx> wrote:
> >
> > Hi John...
> >
> > Thank you for replying.
> >
> > Here is the result of the tests you asked but I do not see nothing abnormal.
> > Actually, your suggestions made me see that:
> >
> > 1) ceph-fuse 9.2.0 is presenting the same behaviour but with less memory
> > consumption, probably, less enought so that it doesn't brake ceph-fuse in
> > our machines with less memory.
> >
> > 2) I see a tremendous number of  ceph-fuse threads launched (around 160).
> >
> > # ps -T -p 3230 -o command,ppid,pid,spid,vsize,rss,%mem,%cpu | wc -l
> > 157
> >
> > # ps -T -p 3230 -o command,ppid,pid,spid,vsize,rss,%mem,%cpu | head -n 10
> > COMMAND                      PPID   PID  SPID    VSZ   RSS %MEM %CPU
> > ceph-fuse --id mount_user -     1  3230  3230 9935240 339780  0.6 0.0
> > ceph-fuse --id mount_user -     1  3230  3231 9935240 339780  0.6 0.1
> > ceph-fuse --id mount_user -     1  3230  3232 9935240 339780  0.6 0.0
> > ceph-fuse --id mount_user -     1  3230  3233 9935240 339780  0.6 0.0
> > ceph-fuse --id mount_user -     1  3230  3234 9935240 339780  0.6 0.0
> > ceph-fuse --id mount_user -     1  3230  3235 9935240 339780  0.6 0.0
> > ceph-fuse --id mount_user -     1  3230  3236 9935240 339780  0.6 0.0
> > ceph-fuse --id mount_user -     1  3230  3237 9935240 339780  0.6 0.0
> > ceph-fuse --id mount_user -     1  3230  3238 9935240 339780  0.6 0.0
> >
> >
> > I do not see a way to actually limit the number of ceph-fuse threads
> > launched  or to limit the max vm size each thread should take.
> >
> > Do you know how to limit those options.
> >
> > Cheers
> >
> > Goncalo
> >
> >
> >
> >
> > 1.> Try running ceph-fuse with valgrind --tool=memcheck to see if it's
> > leaking
> >
> > I have launched ceph-fuse with valgrind in the cluster where there is
> > sufficient memory available, and therefore, there is no object cacher
> > segfault.
> >
> >     $ valgrind --log-file=/tmp/valgrind-ceph-fuse-10.2.2.txt --tool=memcheck
> > ceph-fuse --id mount_user -k /etc/ceph/ceph.client.mount_user.keyring -m
> > X.X.X.8:6789 -r /cephfs /coepp/cephfs
> >
> > This is the output which I get once I unmount the file system after user
> > application execution
> >
> > # cat valgrind-ceph-fuse-10.2.2.txt
> > ==12123== Memcheck, a memory error detector
> > ==12123== Copyright (C) 2002-2012, and GNU GPL'd, by Julian Seward et al.
> > ==12123== Using Valgrind-3.8.1 and LibVEX; rerun with -h for copyright info
> > ==12123== Command: ceph-fuse --id mount_user -k
> > /etc/ceph/ceph.client.mount_user.keyring -m 192.231.127.8:6789 -r /cephfs
> > /coepp/cephfs
> > ==12123== Parent PID: 11992
> > ==12123==
> > ==12123==
> > ==12123== HEAP SUMMARY:
> > ==12123==     in use at exit: 29,129 bytes in 397 blocks
> > ==12123==   total heap usage: 14,824 allocs, 14,427 frees, 648,030 bytes
> > allocated
> > ==12123==
> > ==12123== LEAK SUMMARY:
> > ==12123==    definitely lost: 16 bytes in 1 blocks
> > ==12123==    indirectly lost: 0 bytes in 0 blocks
> > ==12123==      possibly lost: 11,705 bytes in 273 blocks
> > ==12123==    still reachable: 17,408 bytes in 123 blocks
> > ==12123==         suppressed: 0 bytes in 0 blocks
> > ==12123== Rerun with --leak-check=full to see details of leaked memory
> > ==12123==
> > ==12123== For counts of detected and suppressed errors, rerun with: -v
> > ==12123== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 8 from 6)
> > ==12126==
> > ==12126== HEAP SUMMARY:
> > ==12126==     in use at exit: 9,641 bytes in 73 blocks
> > ==12126==   total heap usage: 31,363,579 allocs, 31,363,506 frees,
> > 41,389,143,617 bytes allocated
> > ==12126==
> > ==12126== LEAK SUMMARY:
> > ==12126==    definitely lost: 28 bytes in 1 blocks
> > ==12126==    indirectly lost: 0 bytes in 0 blocks
> > ==12126==      possibly lost: 0 bytes in 0 blocks
> > ==12126==    still reachable: 9,613 bytes in 72 blocks
> > ==12126==         suppressed: 0 bytes in 0 blocks
> > ==12126== Rerun with --leak-check=full to see details of leaked memory
> > ==12126==
> > ==12126== For counts of detected and suppressed errors, rerun with: -v
> > ==12126== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 17 from 9)
> >
> > --- * ---
> >
> > 2.>  Inspect inode count (ceph daemon <path to asok> status) to see if it's
> > obeying its limit
> >
> > This is the output I get once ceph-fuse is mounted but no user application
> > is running
> >
> >     # ceph daemon /var/run/ceph/ceph-client.mount_user.asok status
> >     {
> >         "metadata": {
> >         "ceph_sha1": "45107e21c568dd033c2f0a3107dec8f0b0e58374",
> >         "ceph_version": "ceph version 10.2.2
> > (45107e21c568dd033c2f0a3107dec8f0b0e58374)",
> >         "entity_id": "mount_user",
> >         "hostname": "<some host name>",
> >         "mount_point": "\/coepp\/cephfs",
> >         "root": "\/cephfs"
> >         },
> >         "dentry_count": 0,
> >         "dentry_pinned_count": 0,
> >         "inode_count": 2,
> >         "mds_epoch": 817,
> >         "osd_epoch": 1005,
> >         "osd_epoch_barrier": 0
> >     }
> >
> >
> > This is already when ceph-fuse reached 10g of virtual memory, and user
> > applications are hammering the filesystem.
> >
> >     # ceph daemon /var/run/ceph/ceph-client.mount_user.asok status
> >     {
> >         "metadata": {
> >         "ceph_sha1": "45107e21c568dd033c2f0a3107dec8f0b0e58374",
> >         "ceph_version": "ceph version 10.2.2
> > (45107e21c568dd033c2f0a3107dec8f0b0e58374)",
> >         "entity_id": "mount_user",
> >         "hostname": "<some host name>",
> >         "mount_point": "\/coepp\/cephfs",
> >         "root": "\/cephfs"
> >         },
> >         "dentry_count": 13,
> >         "dentry_pinned_count": 2,
> >         "inode_count": 15,
> >         "mds_epoch": 817,
> >         "osd_epoch": 1005,
> >         "osd_epoch_barrier": 1005
> >     }
> >
> > Once I kill the applications I get
> >
> >     # ceph daemon /var/run/ceph/ceph-client.mount_user.asok status
> >     {
> >         "metadata": {
> >         "ceph_sha1": "45107e21c568dd033c2f0a3107dec8f0b0e58374",
> >         "ceph_version": "ceph version 10.2.2
> > (45107e21c568dd033c2f0a3107dec8f0b0e58374)",
> >         "entity_id": "mount_user",
> >         "hostname": "<some host name>",
> >         "mount_point": "\/coepp\/cephfs",
> >         "root": "\/cephfs"
> >         },
> >         "dentry_count": 38,
> >         "dentry_pinned_count": 3,
> >         "inode_count": 40,
> >         "mds_epoch": 817,
> >         "osd_epoch": 1005,
> >         "osd_epoch_barrier": 1005
> >     }
> >
> > --- * ---
> >
> > 3.>  Enable objectcacher debug (debug objectcacher = 10) and look at the
> > output (from the "trim" lines) to see if it's obeying its limit
> >
> > I've mounted ceph-fuse with debug objectcacher = 10, and filled the host
> > with user applications. I killed the applications when I saw ceph-fuse
> > virtual
> > memory stabilize at around 10g.
> >
> > Greping for the trim lines in the log, this is the structure I've found:
> >
> >     2016-07-11 01:55:46.314888 7f04c57fb700 10 objectcacher trim  start:
> > bytes: max 209715200  clean 0, objects: max 1000 current 1
> >     2016-07-11 01:55:46.314891 7f04c57fb700 10 objectcacher trim finish:
> > max 209715200  clean 0, objects: max 1000 current 1
> >     2016-07-11 01:55:46.315009 7f04c75fe700 10 objectcacher trim  start:
> > bytes: max 209715200  clean 0, objects: max 1000 current 2
> >     2016-07-11 01:55:46.315012 7f04c75fe700 10 objectcacher trim finish:
> > max 209715200  clean 0, objects: max 1000 current 2
> >     <... snip ... >
> >     2016-07-11 01:56:09.444853 7f04c75fe700 10 objectcacher trim  start:
> > bytes: max 209715200  clean 204608008, objects: max 1000 current 55
> >     2016-07-11 01:56:09.444855 7f04c75fe700 10 objectcacher trim finish:
> > max 209715200  clean 204608008, objects: max 1000 current 55
> >     2016-07-11 01:56:09.445010 7f04c57fb700 10 objectcacher trim  start:
> > bytes: max 209715200  clean 204608008, objects: max 1000 current 55
> >     2016-07-11 01:56:09.445011 7f04c57fb700 10 objectcacher trim finish:
> > max 209715200  clean 204608008, objects: max 1000 current 55
> >     2016-07-11 01:56:09.798269 7f04c75fe700 10 objectcacher trim  start:
> > bytes: max 209715200  clean 210943832, objects: max 1000 current 55
> >     2016-07-11 01:56:09.798272 7f04c75fe700 10 objectcacher trim trimming
> > bh[ 0x7f04a8016100 96~59048 0x7f04a8014cd0 (59048) v 3 clean firstbyte=1]
> > waiters = {}
> >     2016-07-11 01:56:09.798284 7f04c75fe700 10 objectcacher trim trimming
> > bh[ 0x7f04b4011550 96~59048 0x7f04b4010430 (59048) v 4 clean firstbyte=1]
> > waiters = {}
> >     2016-07-11 01:56:09.798294 7f04c75fe700 10 objectcacher trim trimming
> > bh[ 0x7f04b001bea0 61760~4132544 0x7f04b4010430 (4132544) v 24 clean
> > firstbyte=71] waiters = {}
> >     2016-07-11 01:56:09.798395 7f04c75fe700 10 objectcacher trim finish:
> > max 209715200  clean 206693192, objects: max 1000 current 55
> >     2016-07-11 01:56:09.798687 7f04c57fb700 10 objectcacher trim  start:
> > bytes: max 209715200  clean 206693192, objects: max 1000 current 55
> >     2016-07-11 01:56:09.798689 7f04c57fb700 10 objectcacher trim finish:
> > max 209715200  clean 206693192, objects: max 1000 current 55
> >     <... snip ...>
> >     2016-07-11 01:56:10.494928 7f04c75fe700 10 objectcacher trim  start:
> > bytes: max 209715200  clean 210806408, objects: max 1000 current 55
> >     2016-07-11 01:56:10.494931 7f04c75fe700 10 objectcacher trim trimming
> > bh[ 0x7f04b401a760 61760~4132544 0x7f04a8014cd0 (4132544) v 32 clean
> > firstbyte=71] waiters = {}
> >     2016-07-11 01:56:10.495058 7f04c75fe700 10 objectcacher trim finish:
> > max 209715200  clean 206673864, objects: max 1000 current 55
> >     <... snip ...>
> >     2016-07-11 01:57:08.333503 7f04c6bfd700 10 objectcacher trim  start:
> > bytes: max 209715200  clean 211528796, objects: max 1000 current 187
> >     2016-07-11 01:57:08.333507 7f04c6bfd700 10 objectcacher trim trimming
> > bh[ 0x7f04b0b370e0 0~4194304 0x7f04b09f2630 (4194304) v 404 clean
> > firstbyte=84] waiters = {}
> >     2016-07-11 01:57:08.333708 7f04c6bfd700 10 objectcacher trim finish:
> > max 209715200  clean 207334492, objects: max 1000 current 187
> >     2016-07-11 01:57:08.616143 7f04c61fc700 10 objectcacher trim  start:
> > bytes: max 209715200  clean 209949683, objects: max 1000 current 188
> >     2016-07-11 01:57:08.616146 7f04c61fc700 10 objectcacher trim trimming
> > bh[ 0x7f04a8bfdd60 0~4194304 0x7f04a8bfe660 (4194304) v 407 clean
> > firstbyte=84] waiters = {}
> >     2016-07-11 01:57:08.616303 7f04c61fc700 10 objectcacher trim finish:
> > max 209715200  clean 205755379, objects: max 1000 current 188
> >     2016-07-11 01:57:08.936060 7f04c57fb700 10 objectcacher trim  start:
> > bytes: max 209715200  clean 205760010, objects: max 1000 current 189
> >     2016-07-11 01:57:08.936063 7f04c57fb700 10 objectcacher trim finish:
> > max 209715200  clean 205760010, objects: max 1000 current 189
> >     2016-07-11 01:58:02.918322 7f04f27f4e40 10 objectcacher release trimming
> > object[100003dffd9.00000000/head oset 0x7f04d4045c98 wr 566/566]
> >     2016-07-11 01:58:02.918335 7f04f27f4e40 10 objectcacher release trimming
> > object[100003dffd5.00000000/head oset 0x7f04d403e378 wr 564/564]
> >     <... snip...>
> >     2016-07-11 01:58:02.924699 7f04f27f4e40 10 objectcacher release trimming
> > object[100003dffc4.0000000f/head oset 0x7f04d402b308 wr 557/557]
> >     2016-07-11 01:58:02.924717 7f04f27f4e40 10 objectcacher release trimming
> > object[100003dffc5.00000000/head oset 0x7f04d40026b8 wr 541/541]
> >     2016-07-11 01:58:02.924769 7f04f27f4e40 10 objectcacher release trimming
> > object[100003dffc8.00000000/head oset 0x7f04d4027818 wr 547/547]
> >     <... snip...>
> >     2016-07-11 01:58:02.925879 7f04f27f4e40 10 objectcacher release_set on
> > 0x7f04d401a568 dne
> >     2016-07-11 01:58:02.925881 7f04f27f4e40 10 objectcacher release_set on
> > 0x7f04d401b078 dne
> >     2016-07-11 01:58:02.957626 7f04e57fb700 10 objectcacher flusher finish
> >
> > So, if I am understanding this correctly, every time the client_oc_size
> > bytes of cached data is above 200M bytes, it is trimmed and the values is
> > well kepted near its limit.
> >
> >
> > --- * ---
> >
> > 4.> See if fuse_disable_pagecache setting makes a difference
> >
> > It doesn't seem to make a difference. I've set in ceph config
> >
> >     # grep fuse /etc/ceph/ceph.conf
> >     fuse_disable_pagecache = true
> >
> > on this client (I guess I do not have to do it in the overall cluster).
> > Then, I've remounted cephfs via ceph-fuse and filled the host with user
> > applications.
> >
> > Almost immediatly this is what I got:
> >
> >       PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
> >     28681 root      20   0 8543m 248m 5948 S  4.0  0.5   0:02.73 ceph-fuse
> >      5369 root      20   0 3131m 231m  12m S  0.0  0.5  26:22.90
> > dsm_om_connsvcd
> >      1429 goncalo   20   0 1595m  98m  32m R 99.5  0.2   1:04.34 python
> >      1098 goncalo   20   0 1596m  86m  20m R 99.9  0.2   1:04.29 python
> >       994 goncalo   20   0 1594m  86m  20m R 99.9  0.2   1:04.16 python
> >     31928 goncalo   20   0 1595m  86m  19m R 99.9  0.2   1:04.76 python
> >     16852 goncalo   20   0 1596m  86m  19m R 99.9  0.2   1:06.16 python
> >     16846 goncalo   20   0 1594m  84m  19m R 99.9  0.2   1:06.05 python
> >     29595 goncalo   20   0 1594m  83m  19m R 100.2  0.2   1:05.57 python
> >     29312 goncalo   20   0 1594m  83m  19m R 99.9  0.2   1:05.01 python
> >     31979 goncalo   20   0 1595m  82m  19m R 100.2  0.2   1:04.82 python
> >     29333 goncalo   20   0 1594m  82m  19m R 99.5  0.2   1:04.94 python
> >     29609 goncalo   20   0 1594m  82m  19m R 99.9  0.2   1:05.07 python
> >
> >
> > 5.> Also, is the version of fuse the same on the nodes running 9.2.0 vs. the
> > nodes running 10.2.2?
> >
> > In 10.2.2 I've compiled with fuse 2.9.7 while in 9.2.0 I've compiled against
> > the default sl6 fuse libs version 2.8.7. However, as I said before, I am
> > seeing the same issue with 9.2.0 (although with a bit less of used virtual
> > memory in total).
> >
> >
> >
> >
> > On 07/08/2016 10:53 PM, John Spray wrote:
> >
> > On Fri, Jul 8, 2016 at 8:01 AM, Goncalo Borges
> > <goncalo.borges@xxxxxxxxxxxxx> wrote:
> >
> > Hi Brad, Patrick, All...
> >
> > I think I've understood this second problem. In summary, it is memory
> > related.
> >
> > This is how I found the source of the problem:
> >
> > 1./ I copied and adapted the user application to run in another cluster of
> > ours. The idea was for me to understand the application and run it myself to
> > collect logs and so on...
> >
> > 2./ Once I submit it to this other cluster, every thing went fine. I was
> > hammering cephfs from multiple nodes without problems. This pointed to
> > something different between the two clusters.
> >
> > 3./ I've started to look better to the segmentation fault message, and
> > assuming that the names of the methods and functions do mean something, the
> > log seems related to issues on the management of objects in cache. This
> > pointed to a memory related problem.
> >
> > 4./ On the cluster where the application run successfully, machines have
> > 48GB of RAM and 96GB of SWAP (don't know why we have such a large SWAP size,
> > it is a legacy setup).
> >
> > # top
> > top - 00:34:01 up 23 days, 22:21,  1 user,  load average: 12.06, 12.12,
> > 10.40
> > Tasks: 683 total,  13 running, 670 sleeping,   0 stopped,   0 zombie
> > Cpu(s): 49.7%us,  0.6%sy,  0.0%ni, 49.7%id,  0.1%wa,  0.0%hi,  0.0%si,
> > 0.0%st
> > Mem:  49409308k total, 29692548k used, 19716760k free,   433064k buffers
> > Swap: 98301948k total,        0k used, 98301948k free, 26742484k cached
> >
> > 5./ I have noticed that ceph-fuse (in 10.2.2) consumes about 1.5 GB of
> > virtual memory when there is no applications using the filesystem.
> >
> >  7152 root      20   0 1108m  12m 5496 S  0.0  0.0   0:00.04 ceph-fuse
> >
> > When I only have one instance of the user application running, ceph-fuse (in
> > 10.2.2) slowly rises with time up to 10 GB of memory usage.
> >
> > if I submit a large number of user applications simultaneously, ceph-fuse
> > goes very fast to ~10GB.
> >
> >   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
> > 18563 root      20   0 10.0g 328m 5724 S  4.0  0.7   1:38.00 ceph-fuse
> >  4343 root      20   0 3131m 237m  12m S  0.0  0.5  28:24.56 dsm_om_connsvcd
> >  5536 goncalo   20   0 1599m  99m  32m R 99.9  0.2  31:35.46 python
> > 31427 goncalo   20   0 1597m  89m  20m R 99.9  0.2  31:35.88 python
> > 20504 goncalo   20   0 1599m  89m  20m R 100.2  0.2  31:34.29 python
> > 20508 goncalo   20   0 1599m  89m  20m R 99.9  0.2  31:34.20 python
> >  4973 goncalo   20   0 1599m  89m  20m R 99.9  0.2  31:35.70 python
> >  1331 goncalo   20   0 1597m  88m  20m R 99.9  0.2  31:35.72 python
> > 20505 goncalo   20   0 1597m  88m  20m R 99.9  0.2  31:34.46 python
> > 20507 goncalo   20   0 1599m  87m  20m R 99.9  0.2  31:34.37 python
> > 28375 goncalo   20   0 1597m  86m  20m R 99.9  0.2  31:35.52 python
> > 20503 goncalo   20   0 1597m  85m  20m R 100.2  0.2  31:34.09 python
> > 20506 goncalo   20   0 1597m  84m  20m R 99.5  0.2  31:34.42 python
> > 20502 goncalo   20   0 1597m  83m  20m R 99.9  0.2  31:34.32 python
> >
> > 6./ On the machines where the user had the segfault, we have 16 GB of RAM
> > and 1GB of SWAP
> >
> > Mem:  16334244k total,  3590100k used, 12744144k free,   221364k buffers
> > Swap:  1572860k total,    10512k used,  1562348k free,  2937276k cached
> >
> > 7./ I think what is happening is that once the user submits his sets of
> > jobs, the memory usage goes to the very limit on this type machine, and the
> > raise is actually to fast that ceph-fuse segfaults before OOM Killer can
> > kill it.
> >
> > 8./ We have run the user application in the same type of machines but with
> > 64 GB of RAM and 1GB of SWAP, and everything goes fine also here.
> >
> >
> > So, in conclusion, our second problem (besides the locks which was fixed by
> > Pat patch) is the memory usage profile of ceph-fuse in 10.2.2 which seems to
> > be very different than what it was in ceph-fuse 9.2.0.
> >
> > Are there any ideas how can we limit the virtual memory usage of ceph-fuse
> > in 10.2.2?
> >
> > The fuse client is designed to limit its cache sizes:
> > client_cache_size (default 16384) inodes of cached metadata
> > client_oc_size (default 200MB) bytes of cached data
> >
> > We do run the fuse client with valgrind during testing, so it it is
> > showing memory leaks in normal usage on your system then that's news.
> >
> > The top output you've posted seems to show that ceph-fuse only
> > actually has 328MB resident though?
> >
> > If you can reproduce the memory growth, then it would be good to:
> >  * Try running ceph-fuse with valgrind --tool=memcheck to see if it's
> > leaking
> >  * Inspect inode count (ceph daemon <path to asok> status) to see if
> > it's obeying its limit
> >  * Enable objectcacher debug (debug objectcacher = 10) and look at the
> > output (from the "trim" lines) to see if it's obeying its limit
> >  * See if fuse_disable_pagecache setting makes a difference
> >
> > Also, is the version of fuse the same on the nodes running 9.2.0 vs.
> > the nodes running 10.2.2?
> >
> > John
> >
> > Cheers
> > Goncalo
> >
> >
> >
> > On 07/08/2016 09:54 AM, Brad Hubbard wrote:
> >
> > Hi Goncalo,
> >
> > If possible it would be great if you could capture a core file for this with
> > full debugging symbols (preferably glibc debuginfo as well). How you do
> > that will depend on the ceph version and your OS but we can offfer help
> > if required I'm sure.
> >
> > Once you have the core do the following.
> >
> > $ gdb /path/to/ceph-fuse core.XXXX
> > (gdb) set pag off
> > (gdb) set log on
> > (gdb) thread apply all bt
> > (gdb) thread apply all bt full
> >
> > Then quit gdb and you should find a file called gdb.txt in your
> > working directory.
> > If you could attach that file to http://tracker.ceph.com/issues/16610
> >
> > Cheers,
> > Brad
> >
> > On Fri, Jul 8, 2016 at 12:06 AM, Patrick Donnelly <pdonnell@xxxxxxxxxx>
> > wrote:
> >
> > On Thu, Jul 7, 2016 at 2:01 AM, Goncalo Borges
> > <goncalo.borges@xxxxxxxxxxxxx> wrote:
> >
> > Unfortunately, the other user application breaks ceph-fuse again (It is a
> > completely different application then in my previous test).
> >
> > We have tested it in 4 machines with 4 cores. The user is submitting 16
> > single core jobs which are all writing different output files (one per job)
> > to a common dir in cephfs. The first 4 jobs run happily and never break
> > ceph-fuse. But the remaining 12 jobs, running in the remaining 3 machines,
> > trigger a segmentation fault, which is completely different from the other
> > case.
> >
> > ceph version 10.2.2 (45107e21c568dd033c2f0a3107dec8f0b0e58374)
> > 1: (()+0x297fe2) [0x7f54402b7fe2]
> > 2: (()+0xf7e0) [0x7f543ecf77e0]
> > 3: (ObjectCacher::bh_write_scattered(std::list<ObjectCacher::BufferHead*,
> > std::allocator<ObjectCacher::BufferHead*> >&)+0x36) [0x7f5440268086]
> > 4: (ObjectCacher::bh_write_adjacencies(ObjectCacher::BufferHead*,
> > std::chrono::time_point<ceph::time_detail::real_clock,
> > std::chrono::duration<unsigned long, std::ratio<1l, 1000000000l> > >, long*,
> > int*)+0x22c) [0x7f5440268a3c]
> > 5: (ObjectCacher::flush(long)+0x1ef) [0x7f5440268cef]
> > 6: (ObjectCacher::flusher_entry()+0xac4) [0x7f5440269a34]
> > 7: (ObjectCacher::FlusherThread::entry()+0xd) [0x7f5440275c6d]
> > 8: (()+0x7aa1) [0x7f543ecefaa1]
> >  9: (clone()+0x6d) [0x7f543df6893d]
> > NOTE: a copy of the executable, or `objdump -rdS <executable>` is needed to
> > interpret this.
> >
> > This one looks like a very different problem. I've created an issue
> > here: http://tracker.ceph.com/issues/16610
> >
> > Thanks for the report and debug log!
> >
> > --
> > Patrick Donnelly
> > _______________________________________________
> > ceph-users mailing list
> > ceph-users@xxxxxxxxxxxxxx
> > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
> >
> >
> >
> > --
> > Goncalo Borges
> > Research Computing
> > ARC Centre of Excellence for Particle Physics at the Terascale
> > School of Physics A28 | University of Sydney, NSW  2006
> > T: +61 2 93511937
> >
> >
> > _______________________________________________
> > ceph-users mailing list
> > ceph-users@xxxxxxxxxxxxxx
> > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
> >
> >
> > --
> > Goncalo Borges
> > Research Computing
> > ARC Centre of Excellence for Particle Physics at the Terascale
> > School of Physics A28 | University of Sydney, NSW  2006
> > T: +61 2 93511937
> >
> >
> > _______________________________________________
> > ceph-users mailing list
> > ceph-users@xxxxxxxxxxxxxx
> > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
> >
> >
> > --
> > Goncalo Borges
> > Research Computing
> > ARC Centre of Excellence for Particle Physics at the Terascale
> > School of Physics A28 | University of Sydney, NSW  2006
> > T: +61 2 93511937
_______________________________________________
ceph-users mailing list
ceph-users@xxxxxxxxxxxxxx
http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com



[Index of Archives]     [Information on CEPH]     [Linux Filesystem Development]     [Ceph Development]     [Ceph Large]     [Linux USB Development]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [xfs]


  Powered by Linux