* Re: backing up ext4 fs, system unresponsive, thrashing like crazy even though swap is unused [not found] <1353851735.22969.18.camel@soupermouf> @ 2012-11-25 19:30 ` Dimitrios Apostolou 2012-11-25 22:41 ` kmemleak failure (was Re: backing up ext4 fs, system unresponsive, thrashing like crazy even though swap is unused) Dimitrios Apostolou ` (2 more replies) 0 siblings, 3 replies; 10+ messages in thread From: Dimitrios Apostolou @ 2012-11-25 19:30 UTC (permalink / raw) To: linux-kernel On Sun, 2012-11-25 at 15:55 +0200, Dimitrios Apostolou wrote: > on an old PIII-500MHz laptop, 128MB RAM, kernel 3.6.6, I started a > backup process (tar|xz -4, nice'd and ionice'd -c3) from ext4 on local > ATA disk to ext3 on external USB disk (USB-2.0 port on PCMCIA card). > Even though earlier system load was minimal, free memory was plenty, the > system now is unresponsive and is thrashing the disk, but the swapfile > is rarely touched. I'm now having the same experience even though I replaced xz (which needed ~50MB RAM) with gzip. Even though I feel the realtime root shell is a bit more responsive than before, the OOM killer is out killing small processes like syslog-ng and systemd-logind... The ext4_inode_cache slab is taking almost all my memory (117MB). Please advise! Thanks, Dimitris ^ permalink raw reply [flat|nested] 10+ messages in thread
* kmemleak failure (was Re: backing up ext4 fs, system unresponsive, thrashing like crazy even though swap is unused) 2012-11-25 19:30 ` backing up ext4 fs, system unresponsive, thrashing like crazy even though swap is unused Dimitrios Apostolou @ 2012-11-25 22:41 ` Dimitrios Apostolou 2012-11-25 23:19 ` Dimitrios Apostolou 2012-11-25 22:59 ` backing up ext4 fs, system unresponsive, thrashing like crazy even though swap is unused Roland Eggner 2012-12-06 14:20 ` Jan Kara 2 siblings, 1 reply; 10+ messages in thread From: Dimitrios Apostolou @ 2012-11-25 22:41 UTC (permalink / raw) To: linux-kernel Hello, I tried running a kmemleak and DEBUG_SLUB enabled kernel, but almost within 5 minutes of starting the backup process, I got: [ 486.863124] kmemleak: Cannot allocate a kmemleak_object structure [ 486.887195] kmemleak: Automatic memory scanning thread ended [ 486.906604] kmemleak: Kernel memory leak detector disabled Any ideas? Thanks, Dimitris ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: kmemleak failure (was Re: backing up ext4 fs, system unresponsive, thrashing like crazy even though swap is unused) 2012-11-25 22:41 ` kmemleak failure (was Re: backing up ext4 fs, system unresponsive, thrashing like crazy even though swap is unused) Dimitrios Apostolou @ 2012-11-25 23:19 ` Dimitrios Apostolou 0 siblings, 0 replies; 10+ messages in thread From: Dimitrios Apostolou @ 2012-11-25 23:19 UTC (permalink / raw) To: linux-kernel On Mon, 2012-11-26 at 00:41 +0200, Dimitrios Apostolou wrote: > Hello, > > I tried running a kmemleak and DEBUG_SLUB enabled kernel, but almost > within 5 minutes of starting the backup process, I got: > > [ 486.863124] kmemleak: Cannot allocate a kmemleak_object structure > [ 486.887195] kmemleak: Automatic memory scanning thread ended > [ 486.906604] kmemleak: Kernel memory leak detector disabled Important detail: I decided to try kmemleak after suspecting a leak because 'echo 3>/proc/sys/vm/drop_caches' left about 90MB out of 118MB of ext4_inode_cache, and I found no way to get rid of that (via remounting filesystems for example). ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: backing up ext4 fs, system unresponsive, thrashing like crazy even though swap is unused 2012-11-25 19:30 ` backing up ext4 fs, system unresponsive, thrashing like crazy even though swap is unused Dimitrios Apostolou 2012-11-25 22:41 ` kmemleak failure (was Re: backing up ext4 fs, system unresponsive, thrashing like crazy even though swap is unused) Dimitrios Apostolou @ 2012-11-25 22:59 ` Roland Eggner 2012-11-25 23:56 ` Alan Cox 2012-12-06 14:20 ` Jan Kara 2 siblings, 1 reply; 10+ messages in thread From: Roland Eggner @ 2012-11-25 22:59 UTC (permalink / raw) To: Dimitrios Apostolou; +Cc: linux-kernel [-- Attachment #1: Type: text/plain, Size: 2178 bytes --] On 2012-11-25 Sunday at 21:30 +0200 Dimitrios Apostolou wrote: > On Sun, 2012-11-25 at 15:55 +0200, Dimitrios Apostolou wrote: > > on an old PIII-500MHz laptop, 128MB RAM, kernel 3.6.6, I started a > > backup process (tar|xz -4, nice'd and ionice'd -c3) from ext4 on local > > ATA disk to ext3 on external USB disk (USB-2.0 port on PCMCIA card). > > Even though earlier system load was minimal, free memory was plenty, the > > system now is unresponsive and is thrashing the disk, but the swapfile > > is rarely touched. > > I'm now having the same experience even though I replaced xz (which > needed ~50MB RAM) with gzip. Even though I feel the realtime root shell > is a bit more responsive than before, the OOM killer is out killing > small processes like syslog-ng and systemd-logind... The > ext4_inode_cache slab is taking almost all my memory (117MB). Please > advise! Hello Dimitrios, I would try a 2.6.27.* kernel, for following reasons: (1) Kernel development since 2.6.27 achieved significant performance improvements at the cost of exploding memory consumption by the kernel for _internal_ data structures. I am currently using a 3.2.34 kernel on a Notebook with 4 G RAM. 0,5 … 1 G RAM is usually occupied just by kernel slab [1]; this memory cannot be swapped, it cannot be released by other means than rebooting, and there seems to be _no_ adjustment to memory pressure. I am surprised, that you have managed to boot a 3.6.* kernel at all with only 128 M RAM. (2) At the time, when I used a PIII-Notebook, kernels 2.6.27 to 2.6.29 where current. Thus chances are good, that a 2.6.27.* kernel will support chipset, PCI bus and devices of your notebook. 2.6.27 got longterm maintainance, the latest release in the linux-stable git repository is 2.6.27.62. So Q @ LKML community: Does anybody know a x86 distribution or live-CD using a 2.6.27.* kernel? [1] Picture described in my LKML message Date: Fri, 20 Jan 2012 01:08:00 +0100 Subject: Re: [kmemleak report 1/2] kernel 3.1.6, x86_64: mm, xfs ?, vfs ? remained the same with _every_ 3.1.* and 3.2.* kernel tried so far. -- Roland [-- Attachment #2: Type: application/pgp-signature, Size: 198 bytes --] ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: backing up ext4 fs, system unresponsive, thrashing like crazy even though swap is unused 2012-11-25 22:59 ` backing up ext4 fs, system unresponsive, thrashing like crazy even though swap is unused Roland Eggner @ 2012-11-25 23:56 ` Alan Cox 2012-11-26 3:11 ` Roland Eggner 0 siblings, 1 reply; 10+ messages in thread From: Alan Cox @ 2012-11-25 23:56 UTC (permalink / raw) To: Roland Eggner; +Cc: Dimitrios Apostolou, linux-kernel > Does anybody know a x86 distribution or live-CD using a 2.6.27.* kernel? Probably not a good idea, there are known exploitable holes in 2.6.27 era kernels and nobody maintains anything that old. I guess RHEL/Centos might work for you. I've not had any problems with leaks in 3.6 but there have been a few reports and its clear that some obscure configurations trigger something bad. Gnome 3 on the other hand leaks like a sieve. ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: backing up ext4 fs, system unresponsive, thrashing like crazy even though swap is unused 2012-11-25 23:56 ` Alan Cox @ 2012-11-26 3:11 ` Roland Eggner 0 siblings, 0 replies; 10+ messages in thread From: Roland Eggner @ 2012-11-26 3:11 UTC (permalink / raw) To: Alan Cox; +Cc: Dimitrios Apostolou, linux-kernel [-- Attachment #1: Type: text/plain, Size: 1085 bytes --] On 2012-11-25 Sunday at 23:56 +0000 Alan Cox wrote: > > Does anybody know a x86 distribution or live-CD using a 2.6.27.* kernel? > > Probably not a good idea, there are known exploitable holes in 2.6.27 era > kernels and nobody maintains anything that old. “old” is relative … cd git/linux-stable && git log -1 --date=iso v2.6.27.62 ........................................................ commit bc4e1a77b06519a01e7aed1125695598e27ddeb2 Author: Willy Tarreau <w@1wt.eu> Date: 2012-03-17 14:03:53 +0100 Linux 2.6.27.62 Signed-off-by: Willy Tarreau <w@1wt.eu> … and surely less exploitable than a system suffering oom-killer actions. Google "linux-2.6.27 download" gives some Ubuntu hits … > I guess RHEL/Centos might work for you. > > I've not had any problems with leaks in 3.6 but there have been a few > reports and its clear that some obscure configurations trigger something > bad. > > Gnome 3 on the other hand leaks like a sieve. For a system with 128 M total RAM, Gnome is obviously off topic. -- Roland [-- Attachment #2: Type: application/pgp-signature, Size: 198 bytes --] ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: backing up ext4 fs, system unresponsive, thrashing like crazy even though swap is unused 2012-11-25 19:30 ` backing up ext4 fs, system unresponsive, thrashing like crazy even though swap is unused Dimitrios Apostolou 2012-11-25 22:41 ` kmemleak failure (was Re: backing up ext4 fs, system unresponsive, thrashing like crazy even though swap is unused) Dimitrios Apostolou 2012-11-25 22:59 ` backing up ext4 fs, system unresponsive, thrashing like crazy even though swap is unused Roland Eggner @ 2012-12-06 14:20 ` Jan Kara 2012-12-06 15:15 ` Dimitrios Apostolou 2 siblings, 1 reply; 10+ messages in thread From: Jan Kara @ 2012-12-06 14:20 UTC (permalink / raw) To: Dimitrios Apostolou; +Cc: linux-kernel On Sun 25-11-12 21:30:00, Dimitrios Apostolou wrote: > On Sun, 2012-11-25 at 15:55 +0200, Dimitrios Apostolou wrote: > > on an old PIII-500MHz laptop, 128MB RAM, kernel 3.6.6, I started a > > backup process (tar|xz -4, nice'd and ionice'd -c3) from ext4 on local > > ATA disk to ext3 on external USB disk (USB-2.0 port on PCMCIA card). > > Even though earlier system load was minimal, free memory was plenty, the > > system now is unresponsive and is thrashing the disk, but the swapfile > > is rarely touched. > > I'm now having the same experience even though I replaced xz (which > needed ~50MB RAM) with gzip. Even though I feel the realtime root shell > is a bit more responsive than before, the OOM killer is out killing > small processes like syslog-ng and systemd-logind... The > ext4_inode_cache slab is taking almost all my memory (117MB). Please > advise! Hmm, it seems commit 4eff96dd5283a102e0c1cac95247090be74a38ed might be interesting for you. It landed in -stable kernels recently as well if I remember right... Honza -- Jan Kara <jack@suse.cz> SUSE Labs, CR ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: backing up ext4 fs, system unresponsive, thrashing like crazy even though swap is unused 2012-12-06 14:20 ` Jan Kara @ 2012-12-06 15:15 ` Dimitrios Apostolou 2012-12-06 16:43 ` Jan Kara 0 siblings, 1 reply; 10+ messages in thread From: Dimitrios Apostolou @ 2012-12-06 15:15 UTC (permalink / raw) To: Jan Kara; +Cc: linux-kernel On Thu, 6 Dec 2012, Jan Kara wrote: > On Sun 25-11-12 21:30:00, Dimitrios Apostolou wrote: >> On Sun, 2012-11-25 at 15:55 +0200, Dimitrios Apostolou wrote: >>> on an old PIII-500MHz laptop, 128MB RAM, kernel 3.6.6, I started a >>> backup process (tar|xz -4, nice'd and ionice'd -c3) from ext4 on local >>> ATA disk to ext3 on external USB disk (USB-2.0 port on PCMCIA card). >>> Even though earlier system load was minimal, free memory was plenty, the >>> system now is unresponsive and is thrashing the disk, but the swapfile >>> is rarely touched. >> >> I'm now having the same experience even though I replaced xz (which >> needed ~50MB RAM) with gzip. Even though I feel the realtime root shell >> is a bit more responsive than before, the OOM killer is out killing >> small processes like syslog-ng and systemd-logind... The >> ext4_inode_cache slab is taking almost all my memory (117MB). Please >> advise! > Hmm, it seems commit 4eff96dd5283a102e0c1cac95247090be74a38ed might be > interesting for you. It landed in -stable kernels recently as well if I > remember right... Thanks, I appreciate your help as I'm stuck in a dead end now, and I've been trying to write some debug hook that prints all ext4_inodes and the reason they are pinned (is there an easy way to find this out?). So maybe there is a typo in the SHA1 sum you provided? Gitweb can't find it in Linus' tree. Thanks, Dimitris ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: backing up ext4 fs, system unresponsive, thrashing like crazy even though swap is unused 2012-12-06 15:15 ` Dimitrios Apostolou @ 2012-12-06 16:43 ` Jan Kara 2012-12-07 15:26 ` Dimitrios Apostolou 0 siblings, 1 reply; 10+ messages in thread From: Jan Kara @ 2012-12-06 16:43 UTC (permalink / raw) To: Dimitrios Apostolou; +Cc: Jan Kara, linux-kernel [-- Attachment #1: Type: text/plain, Size: 1692 bytes --] On Thu 06-12-12 17:15:37, Dimitrios Apostolou wrote: > On Thu, 6 Dec 2012, Jan Kara wrote: > >On Sun 25-11-12 21:30:00, Dimitrios Apostolou wrote: > >>On Sun, 2012-11-25 at 15:55 +0200, Dimitrios Apostolou wrote: > >>>on an old PIII-500MHz laptop, 128MB RAM, kernel 3.6.6, I started a > >>>backup process (tar|xz -4, nice'd and ionice'd -c3) from ext4 on local > >>>ATA disk to ext3 on external USB disk (USB-2.0 port on PCMCIA card). > >>>Even though earlier system load was minimal, free memory was plenty, the > >>>system now is unresponsive and is thrashing the disk, but the swapfile > >>>is rarely touched. > >> > >>I'm now having the same experience even though I replaced xz (which > >>needed ~50MB RAM) with gzip. Even though I feel the realtime root shell > >>is a bit more responsive than before, the OOM killer is out killing > >>small processes like syslog-ng and systemd-logind... The > >>ext4_inode_cache slab is taking almost all my memory (117MB). Please > >>advise! > > Hmm, it seems commit 4eff96dd5283a102e0c1cac95247090be74a38ed might be > >interesting for you. It landed in -stable kernels recently as well if I > >remember right... > > Thanks, I appreciate your help as I'm stuck in a dead end now, and > I've been trying to write some debug hook that prints all > ext4_inodes and the reason they are pinned (is there an easy way to > find this out?). > > So maybe there is a typo in the SHA1 sum you provided? Gitweb can't > find it in Linus' tree. Strange. You are right gitweb doesn't show the SHA1 but I can see it in my git repo I pulled from Linus. Anyway, I've attached the fix for your convenience. Honza -- Jan Kara <jack@suse.cz> SUSE Labs, CR [-- Attachment #2: 0001-writeback-Put-unused-inodes-to-LRU-after-writeback-c.patch --] [-- Type: text/x-patch, Size: 3356 bytes --] >From 9501fee10d8594ab8ee7deb749fb48c1d3a7985e Mon Sep 17 00:00:00 2001 From: Jan Kara <jack@suse.cz> Date: Mon, 19 Nov 2012 20:01:16 +0100 Subject: [PATCH v3] writeback: Put unused inodes to LRU after writeback completion Commit 169ebd90 removed iget-iput pair from inode writeback. As a side effect, inodes that are dirty during iput_final() call won't be ever added to inode LRU (iput_final() doesn't add dirty inodes to LRU and later when the inode is cleaned there's noone to add the inode there). Thus inodes are effectively unreclaimable until someone looks them up again. Practical effect of this bug is limited by the fact that inodes are pinned by a dentry for long enough that the inode gets cleaned. But still the bug can have nasty consequences leading up to OOM conditions under certain circumstances. Following can easily reproduce the problem: for (( i = 0; i < 1000; i++ )); do mkdir $i for (( j = 0; j < 1000; j++ )); do touch $i/$j echo 2 > /proc/sys/vm/drop_caches done done then one needs to run 'sync; ls -lR' to make inodes reclaimable again. We fix the issue by inserting unused clean inodes into the LRU after writeback finishes in inode_sync_complete(). CC: Al Viro <viro@zeniv.linux.org.uk> CC: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> CC: stable@vger.kernel.org # >= 3.5 Reported-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Signed-off-by: Jan Kara <jack@suse.cz> --- fs/fs-writeback.c | 2 ++ fs/inode.c | 16 ++++++++++++++-- fs/internal.h | 1 + 3 files changed, 17 insertions(+), 2 deletions(-) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 51ea267..3e3422f 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -228,6 +228,8 @@ static void requeue_io(struct inode *inode, struct bdi_writeback *wb) static void inode_sync_complete(struct inode *inode) { inode->i_state &= ~I_SYNC; + /* If inode is clean an unused, put it into LRU now... */ + inode_add_lru(inode); /* Waiters must see I_SYNC cleared before being woken up */ smp_mb(); wake_up_bit(&inode->i_state, __I_SYNC); diff --git a/fs/inode.c b/fs/inode.c index b03c719..64999f1 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -408,6 +408,19 @@ static void inode_lru_list_add(struct inode *inode) spin_unlock(&inode->i_sb->s_inode_lru_lock); } +/* + * Add inode to LRU if needed (inode is unused and clean). + * + * Needs inode->i_lock held. + */ +void inode_add_lru(struct inode *inode) +{ + if (!(inode->i_state & (I_DIRTY | I_SYNC | I_FREEING | I_WILL_FREE)) && + !atomic_read(&inode->i_count) && inode->i_sb->s_flags & MS_ACTIVE) + inode_lru_list_add(inode); +} + + static void inode_lru_list_del(struct inode *inode) { spin_lock(&inode->i_sb->s_inode_lru_lock); @@ -1390,8 +1403,7 @@ static void iput_final(struct inode *inode) if (!drop && (sb->s_flags & MS_ACTIVE)) { inode->i_state |= I_REFERENCED; - if (!(inode->i_state & (I_DIRTY|I_SYNC))) - inode_lru_list_add(inode); + inode_add_lru(inode); spin_unlock(&inode->i_lock); return; } diff --git a/fs/internal.h b/fs/internal.h index 916b7cb..2f6af7f 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -110,6 +110,7 @@ extern int open_check_o_direct(struct file *f); * inode.c */ extern spinlock_t inode_sb_list_lock; +extern void inode_add_lru(struct inode *inode); /* * fs-writeback.c -- 1.7.1 ^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: backing up ext4 fs, system unresponsive, thrashing like crazy even though swap is unused 2012-12-06 16:43 ` Jan Kara @ 2012-12-07 15:26 ` Dimitrios Apostolou 0 siblings, 0 replies; 10+ messages in thread From: Dimitrios Apostolou @ 2012-12-07 15:26 UTC (permalink / raw) To: Jan Kara; +Cc: linux-kernel, Roland Eggner, Catalin Marinas, Theodore Ts'o Hi Jan, thanks for your help, with this commit I can't reproduce the problem. The problematic workload is no more inflating the ext4_inode_cache, in fact I've been able to run even heavier workloads with the ext4_inode_cache never surpassing 2-4MB. Thanks everyone for helping, Dimitris On Thu, 6 Dec 2012, Jan Kara wrote: > On Thu 06-12-12 17:15:37, Dimitrios Apostolou wrote: >> On Thu, 6 Dec 2012, Jan Kara wrote: >>> On Sun 25-11-12 21:30:00, Dimitrios Apostolou wrote: >>>> On Sun, 2012-11-25 at 15:55 +0200, Dimitrios Apostolou wrote: >>>>> on an old PIII-500MHz laptop, 128MB RAM, kernel 3.6.6, I started a >>>>> backup process (tar|xz -4, nice'd and ionice'd -c3) from ext4 on local >>>>> ATA disk to ext3 on external USB disk (USB-2.0 port on PCMCIA card). >>>>> Even though earlier system load was minimal, free memory was plenty, the >>>>> system now is unresponsive and is thrashing the disk, but the swapfile >>>>> is rarely touched. >>>> >>>> I'm now having the same experience even though I replaced xz (which >>>> needed ~50MB RAM) with gzip. Even though I feel the realtime root shell >>>> is a bit more responsive than before, the OOM killer is out killing >>>> small processes like syslog-ng and systemd-logind... The >>>> ext4_inode_cache slab is taking almost all my memory (117MB). Please >>>> advise! >>> Hmm, it seems commit 4eff96dd5283a102e0c1cac95247090be74a38ed might be >>> interesting for you. It landed in -stable kernels recently as well if I >>> remember right... >> >> Thanks, I appreciate your help as I'm stuck in a dead end now, and >> I've been trying to write some debug hook that prints all >> ext4_inodes and the reason they are pinned (is there an easy way to >> find this out?). >> >> So maybe there is a typo in the SHA1 sum you provided? Gitweb can't >> find it in Linus' tree. > Strange. You are right gitweb doesn't show the SHA1 but I can see it in > my git repo I pulled from Linus. Anyway, I've attached the fix for your > convenience. > > Honza > > -- > Jan Kara <jack@suse.cz> > SUSE Labs, CR > ^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2012-12-07 15:26 UTC | newest] Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- [not found] <1353851735.22969.18.camel@soupermouf> 2012-11-25 19:30 ` backing up ext4 fs, system unresponsive, thrashing like crazy even though swap is unused Dimitrios Apostolou 2012-11-25 22:41 ` kmemleak failure (was Re: backing up ext4 fs, system unresponsive, thrashing like crazy even though swap is unused) Dimitrios Apostolou 2012-11-25 23:19 ` Dimitrios Apostolou 2012-11-25 22:59 ` backing up ext4 fs, system unresponsive, thrashing like crazy even though swap is unused Roland Eggner 2012-11-25 23:56 ` Alan Cox 2012-11-26 3:11 ` Roland Eggner 2012-12-06 14:20 ` Jan Kara 2012-12-06 15:15 ` Dimitrios Apostolou 2012-12-06 16:43 ` Jan Kara 2012-12-07 15:26 ` Dimitrios Apostolou
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