There is potential for deadlock in the l2arc_feed thread if KM_PUSHPAGE is not used for the allocations made in l2arc_write_buffers. Specifically, if KM_PUSHPAGE is not used for these allocations, it is possible for reclaim to be triggered which can cause the l2arc_feed thread to deadlock itself on the ARC_mru mutex. An example of this is demonstrated in the following backtrace of the l2arc_feed thread: crash> bt 4123 PID: 4123 TASK: ffff88062f8c1500 CPU: 6 COMMAND: "l2arc_feed" 0 [ffff88062511d610] schedule at ffffffff814eeee0 1 [ffff88062511d6d8] __mutex_lock_slowpath at ffffffff814f057e 2 [ffff88062511d748] mutex_lock at ffffffff814f041b 3 [ffff88062511d768] arc_evict at ffffffffa05130ca [zfs] 4 [ffff88062511d858] arc_adjust at ffffffffa05139a9 [zfs] 5 [ffff88062511d878] arc_shrink at ffffffffa0513a95 [zfs] 6 [ffff88062511d898] arc_kmem_reap_now at ffffffffa0513be8 [zfs] 7 [ffff88062511d8c8] arc_shrinker_func at ffffffffa0513ccc [zfs] 8 [ffff88062511d8f8] shrink_slab at ffffffff8112a17a 9 [ffff88062511d958] do_try_to_free_pages at ffffffff8112bfdf 10 [ffff88062511d9e8] try_to_free_pages at ffffffff8112c3ed 11 [ffff88062511da98] __alloc_pages_nodemask at ffffffff8112431d 12 [ffff88062511dbb8] kmem_getpages at ffffffff8115e632 13 [ffff88062511dbe8] fallback_alloc at ffffffff8115f24a 14 [ffff88062511dc68] ____cache_alloc_node at ffffffff8115efc9 15 [ffff88062511dcc8] __kmalloc at ffffffff8115fbf9 16 [ffff88062511dd18] kmem_alloc_debug at ffffffffa047b8cb [spl] 17 [ffff88062511dda8] l2arc_feed_thread at ffffffffa0511e71 [zfs] 18 [ffff88062511dea8] thread_generic_wrapper at ffffffffa047d1a1 [spl] 19 [ffff88062511dee8] kthread at ffffffff81090a86 20 [ffff88062511df48] kernel_thread at ffffffff8100c14a Signed-off-by: Prakash Surya <surya1@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> |
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cmd | ||
config | ||
dracut | ||
etc | ||
include | ||
lib | ||
man | ||
module | ||
patches | ||
scripts | ||
udev | ||
.gitignore | ||
AUTHORS | ||
COPYING | ||
COPYRIGHT | ||
ChangeLog | ||
DISCLAIMER | ||
META | ||
Makefile.am | ||
Makefile.in | ||
OPENSOLARIS.LICENSE | ||
PKGBUILD-zfs-modules.in | ||
PKGBUILD-zfs.in | ||
README.markdown | ||
ZFS.RELEASE | ||
autogen.sh | ||
configure | ||
configure.ac | ||
zfs-modules.spec.in | ||
zfs-script-config.sh.in | ||
zfs.spec.in | ||
zfs_config.h.in |
README.markdown
Native ZFS for Linux! ZFS is an advanced file system and volume manager which was originally developed for Solaris. It has been successfully ported to FreeBSD and now there is a functional Linux ZFS kernel port too. The port currently includes a fully functional and stable SPA, DMU, and ZVOL with a ZFS Posix Layer (ZPL) on the way!
$ ./configure
$ make pkg
Full documentation for building, configuring, and using ZFS can be found at: http://zfsonlinux.org