freebsd-dev/sys/kern
Jonathan T. Looney 54503a13d8 Add a safety net to reclaim mbufs when one of the mbuf zones become
exhausted.

It is possible for a bug in the code (or, theoretically, even unusual
network conditions) to exhaust all possible mbufs or mbuf clusters.
When this occurs, things can grind to a halt fairly quickly. However,
we currently do not call mb_reclaim() unless the entire system is
experiencing a low-memory condition.

While it is best to try to prevent exhaustion of one of the mbuf zones,
it would also be useful to have a mechanism to attempt to recover from
these situations by freeing "expendable" mbufs.

This patch makes two changes:

a) The patch adds a generic API to the UMA zone allocator to set a
function that should be called when an allocation fails because the
zone limit has been reached. Because of the way this function can be
called, it really should do minimal work.

b) The patch uses this API to try to free mbufs when an allocation
fails from one of the mbuf zones because the zone limit has been
reached. The function schedules a callout to run mb_reclaim().

Differential Revision:	https://reviews.freebsd.org/D3864
Reviewed by:	gnn
Comments by:	rrs, glebius
MFC after:	2 weeks
Sponsored by:	Juniper Networks
2015-12-20 02:05:33 +00:00
..
bus_if.m Add a note to the effect that BUS_ADD_CHILD calls 2015-10-28 18:53:18 +00:00
capabilities.conf Add futimens and utimensat system calls. 2015-01-23 21:07:08 +00:00
clock_if.m
cpufreq_if.m
device_if.m Change the default method for device_quiesce() to return 0 instead of 2015-01-08 21:46:28 +00:00
genassym.sh genassym.sh: call nm(1) with NMFLAGS. 2015-08-14 22:57:13 +00:00
imgact_aout.c Remove sv_prepsyscall, sv_sigsize and sv_sigtbl members of the struct 2015-11-28 08:49:07 +00:00
imgact_binmisc.c At the suggestion of jhb, replace atomic_set/clear calls with use of 2015-06-24 15:52:26 +00:00
imgact_elf32.c
imgact_elf64.c
imgact_elf.c Replace magic value ELF note type with NT_FREEBSD_ABI_TAG 2015-12-07 18:43:27 +00:00
imgact_gzip.c Implement lockless resource limits. 2015-06-10 10:48:12 +00:00
imgact_shell.c Allow multiple image activators to run on the same execution by changing 2014-09-04 21:31:25 +00:00
inflate.c
init_main.c Remove sv_prepsyscall, sv_sigsize and sv_sigtbl members of the struct 2015-11-28 08:49:07 +00:00
init_sysent.c Missing regen after last change to sys/kern/syscalls.master. 2015-10-22 21:30:39 +00:00
kern_acct.c acct: create a special plimit object and set it for exiting processes 2013-06-30 19:08:06 +00:00
kern_alq.c Prevent alq from panic when the invalid alq_file path specified. 2014-04-05 16:54:47 +00:00
kern_clock.c Initialize ticks so that it wraps 10 minutes after boot to increase the 2015-02-05 01:43:21 +00:00
kern_clocksource.c Fix typo in comment. 2015-07-20 09:37:42 +00:00
kern_condvar.c Revert r282971. It depends on condvar consumers not destroying condvars 2015-05-21 16:43:26 +00:00
kern_conf.c Fix for out of order device destruction notifications when using the 2015-03-22 13:11:56 +00:00
kern_cons.c CALLOUT_MPSAFE has lost its meaning since r141428, i.e., for more than ten 2015-05-22 17:05:21 +00:00
kern_context.c
kern_cpu.c Pull in r267961 and r267973 again. Fix for issues reported will follow. 2014-06-28 03:56:17 +00:00
kern_cpuset.c Un-static cpuset_which() - it's useful in other contexts, such as some 2015-06-26 04:14:05 +00:00
kern_ctf.c Don't specify a resid parameter if we're just going to ignore it. Instead, 2015-02-20 20:49:00 +00:00
kern_descrip.c fd: implement kern.proc.nfds sysctl 2015-11-07 00:18:14 +00:00
kern_dtrace.c Commit the rest of the changes that were intended to be part of r266826. 2014-05-29 01:42:22 +00:00
kern_dump.c - Unbreak dumpsys(9) on sparc64 after r276772 2015-11-16 23:02:33 +00:00
kern_environment.c Test if 'env' is NULL before doing memset() and strlen(), 2014-10-23 18:23:50 +00:00
kern_et.c Trivial change / forced-commit to document prior change that slipped in 2015-03-16 19:29:19 +00:00
kern_event.c kqueue: simplify kern_kqueue by not refing/unrefing creds too early 2015-09-23 12:45:08 +00:00
kern_exec.c Fix style issues around existing SDT probes. 2015-12-16 23:39:27 +00:00
kern_exit.c Fix style issues around existing SDT probes. 2015-12-16 23:39:27 +00:00
kern_fail.c Use a regular sbuf + SYSCTL_OUT() rather than sbuf_new_for_sysctl() with 2015-03-16 19:18:45 +00:00
kern_ffclock.c The SYSCTL data pointers can come from userspace and must not be 2014-10-28 12:00:39 +00:00
kern_fork.c Fix style issues around existing SDT probes. 2015-12-16 23:39:27 +00:00
kern_gzio.c Move zlib.c from net to libkern. 2015-04-22 14:38:58 +00:00
kern_hhook.c Check that hhk_helper pointer isn't NULL before access. 2015-11-25 07:14:58 +00:00
kern_idle.c
kern_intr.c The part of r285680 which removed release semantic for two stores to 2015-07-21 14:39:34 +00:00
kern_jail.c Fix jail name checking that disallowed anything that starts with '0'. 2015-12-15 17:25:00 +00:00
kern_khelp.c Cleanup and simplification in khelp_{register|deregister}_helper(). No 2013-06-15 06:45:17 +00:00
kern_kthread.c Limit rights on process descriptors. 2015-07-31 10:21:58 +00:00
kern_ktr.c Expand ktr_mask to be a 64-bit unsigned integer. 2015-05-22 11:09:41 +00:00
kern_ktrace.c Pull in r267961 and r267973 again. Fix for issues reported will follow. 2014-06-28 03:56:17 +00:00
kern_linker.c Create the MDT_PNP_INFO metadata record to communicate PNP info about 2015-12-11 05:27:53 +00:00
kern_lock.c Don't modify curthread->td_locks unless INVARIANTS is enabled. 2015-08-02 00:03:08 +00:00
kern_lockf.c Improve style and fix a possible use-after-free case introduced in r268384 2015-01-10 06:48:35 +00:00
kern_lockstat.c Consistently use a reader/writer flag for lockstat probes in rwlock(9) and 2015-07-19 22:24:33 +00:00
kern_loginclass.c Speed up rctl operation with large rulesets, by holding the lock 2015-11-15 12:10:51 +00:00
kern_malloc.c Don't make assertions about td_critnest when the scheduler is stopped. 2015-12-11 20:05:07 +00:00
kern_mbuf.c Add a safety net to reclaim mbufs when one of the mbuf zones become 2015-12-20 02:05:33 +00:00
kern_mib.c Export various helper variables describing the layout and size of 2015-11-12 22:00:59 +00:00
kern_module.c Provide better debug message on kernel module name clash. 2015-10-10 09:21:55 +00:00
kern_mtxpool.c Garbage collect mtxpool_lockbuilder, the mutex pool historically used 2014-05-02 07:57:40 +00:00
kern_mutex.c Don't modify curthread->td_locks unless INVARIANTS is enabled. 2015-08-02 00:03:08 +00:00
kern_ntptime.c Use the monotonic (uptime) counter rather than time-of-day to measure elapsed 2015-07-12 18:38:17 +00:00
kern_numa.c Add an initial NUMA affinity/policy configuration for threads and processes. 2015-07-11 15:21:37 +00:00
kern_osd.c Pull in r267961 and r267973 again. Fix for issues reported will follow. 2014-06-28 03:56:17 +00:00
kern_physio.c Add missing NULL check in physio(). 2015-10-29 13:53:37 +00:00
kern_pmc.c Pull in r267961 and r267973 again. Fix for issues reported will follow. 2014-06-28 03:56:17 +00:00
kern_poll.c When a kernel has DEVICE_POLLING turned on but no drivers have 2015-04-14 14:22:34 +00:00
kern_priv.c Pull in r267961 and r267973 again. Fix for issues reported will follow. 2014-06-28 03:56:17 +00:00
kern_proc.c proc: fix a race which could result in dereference of bad p_pgrp pointer on fork 2015-12-18 16:33:15 +00:00
kern_procctl.c If process becomes reaper (procctl(PROC_REAP_ACQUIRE)) while already 2015-08-20 22:44:26 +00:00
kern_prot.c Get rid of lim_update_thread and cred_update_thread. 2015-07-16 14:30:11 +00:00
kern_racct.c Fix style issues around existing SDT probes. 2015-12-16 23:39:27 +00:00
kern_rangelock.c Change the queue of locks in kern_rangelock.c from holding lock requests in 2013-08-15 20:19:17 +00:00
kern_rctl.c Tweak comments. 2015-12-13 11:30:36 +00:00
kern_resource.c Speed up rctl operation with large rulesets, by holding the lock 2015-11-15 12:10:51 +00:00
kern_rmlock.c Threads holding a read lock of a sleepable rm lock are not permitted 2015-09-15 22:16:21 +00:00
kern_rwlock.c Don't modify curthread->td_locks unless INVARIANTS is enabled. 2015-08-02 00:03:08 +00:00
kern_sdt.c Print a backtrace if the SDT(9) stub gets called so that there's at least 2014-02-22 01:41:45 +00:00
kern_sema.c
kern_sharedpage.c Split kerne timekeep ABI structure vdso_sv_tk out of the struct 2015-11-23 07:09:35 +00:00
kern_shutdown.c Disable suspend when we're shutting down. This solves the "tell FreeBSD 2015-10-01 10:52:26 +00:00
kern_sig.c Fix style issues around existing SDT probes. 2015-12-16 23:39:27 +00:00
kern_switch.c Revert for r277213: 2015-01-22 11:12:42 +00:00
kern_sx.c Don't modify curthread->td_locks unless INVARIANTS is enabled. 2015-08-02 00:03:08 +00:00
kern_synch.c Remove several write-only variables, all reported by the gcc 4.9 2015-05-29 13:24:17 +00:00
kern_syscalls.c Implement lockless resource limits. 2015-06-10 10:48:12 +00:00
kern_sysctl.c Flesh out sysctl types further (follow-up of r290475) 2015-11-07 18:26:32 +00:00
kern_tc.c Define fhard in pps_event(..) only when PPS_SYNC is defined to mute 2015-11-02 03:14:37 +00:00
kern_thr.c Add an API for easily creating userspace threads in kernelspace. 2015-07-20 10:20:04 +00:00
kern_thread.c Mark struct thread zone as type-stable. 2015-10-20 20:29:21 +00:00
kern_time.c Fix an off by one in ppsratecheck(). If you asked for N=1 you'd get one, 2015-01-11 20:48:29 +00:00
kern_timeout.c Fix style issues around existing SDT probes. 2015-12-16 23:39:27 +00:00
kern_umtx.c Minor (and incomplete) style cleanup. 2015-10-30 20:47:42 +00:00
kern_uuid.c Fix a bug in be_uuid_dec(); it called le16dec() instead of be16dec(), 2014-02-13 22:24:36 +00:00
kern_xxx.c
ksched.c Use P1B_PRIO_MAX to designate max posix priority for the RR/FIFO 2015-08-30 18:02:57 +00:00
link_elf_obj.c Add support for weak symbols to the kernel linkers. It means that 2015-09-20 01:27:59 +00:00
link_elf.c Have elf_lookup() return an error if the specified non-weak symbol could 2015-11-03 03:29:35 +00:00
linker_if.m
Make.tags.inc Bring the tags and links entries for amd64 up to date. 2015-10-27 22:59:24 +00:00
Makefile
makesyscalls.sh Rename remaining linux32 symbols such as linux_sysent[] and 2015-10-22 21:28:20 +00:00
md4c.c
md5c.c
p1003_1b.c In preparation for switching linuxulator to the use the native 1:1 2015-05-24 14:44:06 +00:00
pic_if.m [intrng] Migrate the intrng code from sys/arm/arm to sys/kern/subr_intr.c. 2015-12-18 05:43:59 +00:00
posix4_mib.c
sched_4bsd.c kgdb uses td_oncpu to determine if a thread is running and should use 2015-08-03 20:43:36 +00:00
sched_ule.c Summary: Add the interactivity equations to the header comment for our 2015-08-26 16:36:41 +00:00
serdev_if.m
stack_protector.c Use nitems() macro instead of __arraycount() 2015-06-16 20:19:00 +00:00
subr_acl_nfs4.c Expose an interface to determine if an ACE is inherited. 2015-09-04 00:14:20 +00:00
subr_acl_posix1e.c
subr_autoconf.c
subr_blist.c
subr_bufring.c
subr_bus_dma.c Add asynchronous command support to the pass(4) driver, and the new 2015-12-03 20:54:55 +00:00
subr_bus.c Huge cleanup of random(4) code. 2015-06-30 17:00:45 +00:00
subr_busdma_bufalloc.c Fix printf format to allow for bus_size_t not being u_long on all platforms. 2015-10-20 03:25:17 +00:00
subr_capability.c capsicum: plug spurious memset in __cap_rights_init 2015-12-01 02:48:42 +00:00
subr_clock.c For architectures where time_t is wide enough, in particular, 64bit 2014-12-12 09:37:18 +00:00
subr_counter.c Create two public UMA_ZONE_PCPU zones: 64 bit sized and pointer sized. 2014-02-10 19:59:46 +00:00
subr_devstat.c Fix multiple incorrect SYSCTL arguments in the kernel: 2014-10-21 07:31:21 +00:00
subr_disk.c
subr_dummy_vdso_tc.c Update the vdso timehands only via tc_windup(). 2015-01-20 03:54:30 +00:00
subr_eventhandler.c
subr_fattime.c Where appropriate, use the modern terms for the one true time base 2014-12-21 05:07:11 +00:00
subr_firmware.c Create a dedicated function for ensuring that cdir and rdir are populated. 2015-07-11 16:22:48 +00:00
subr_hash.c
subr_hints.c Add a new device control utility for new-bus devices called devctl. This 2015-02-06 16:09:01 +00:00
subr_intr.c [intrng] Migrate the intrng code from sys/arm/arm to sys/kern/subr_intr.c. 2015-12-18 05:43:59 +00:00
subr_kdb.c Fix multiple incorrect SYSCTL arguments in the kernel: 2014-10-21 07:31:21 +00:00
subr_kobj.c
subr_lock.c Add _NEW flag to mtx(9), sx(9), rmlock(9) and rwlock(9). 2014-12-13 21:00:10 +00:00
subr_log.c
subr_mbpool.c All mbuf external free functions never fail, so let them be void. 2014-07-11 13:58:48 +00:00
subr_mchain.c
subr_module.c preload_search_info: make sure mod is set 2015-08-21 15:57:57 +00:00
subr_msgbuf.c Pull in r267961 and r267973 again. Fix for issues reported will follow. 2014-06-28 03:56:17 +00:00
subr_param.c Ensure that maxproc does not exceed pid_max, at the time of boot. 2015-09-21 15:02:59 +00:00
subr_pcpu.c Create two public UMA_ZONE_PCPU zones: 64 bit sized and pointer sized. 2014-02-10 19:59:46 +00:00
subr_pctrie.c
subr_power.c
subr_prf.c Add vlog(9). 2015-11-19 05:50:22 +00:00
subr_prof.c The process spin lock currently has the following distinct uses: 2014-11-26 14:10:00 +00:00
subr_rman.c When dumping an rman in DDB, include the RID of each resource. 2015-11-05 23:12:23 +00:00
subr_rtc.c
subr_sbuf.c Fail the sbuf if vsnprintf(3) fails. 2015-10-02 09:23:14 +00:00
subr_scanf.c
subr_sfbuf.c Move KASSERT into locked region. 2014-08-11 15:06:07 +00:00
subr_sglist.c Fix a couple of panics when detaching from a cxgbe/cxl interface that was 2015-01-26 16:26:28 +00:00
subr_sleepqueue.c Revert for r277213: 2015-01-22 11:12:42 +00:00
subr_smp.c Since r289279 bufinit() uses mp_ncpus, but some architectures set this 2015-11-08 14:26:50 +00:00
subr_stack.c Add support for a configurable output channel to witness(4). 2015-11-19 05:56:59 +00:00
subr_syscall.c Support an arbitrary number of arguments to DTrace syscall probes. 2015-12-17 00:00:27 +00:00
subr_taskqueue.c This fixes several places where callout_stops return is examined. The 2015-11-13 22:51:35 +00:00
subr_terminal.c vt(4): Adjust the cursor position after changing the window size 2014-11-01 17:05:15 +00:00
subr_trap.c racct: perform a lockless check for p_throttled 2015-07-13 22:52:11 +00:00
subr_turnstile.c ddb: finish converting boolean values. 2015-05-21 15:16:18 +00:00
subr_uio.c Add asynchronous command support to the pass(4) driver, and the new 2015-12-03 20:54:55 +00:00
subr_unit.c Move the definition of the struct unrhdr into a separate header file, 2013-08-30 07:37:45 +00:00
subr_vmem.c CALLOUT_MPSAFE has lost its meaning since r141428, i.e., for more than ten 2015-05-22 17:05:21 +00:00
subr_witness.c The buffer passed to an sbuf drain callback is not necessarily 2015-11-23 18:45:35 +00:00
sys_capability.c Introduce kern_cap_rights_limit(). 2015-08-11 08:43:50 +00:00
sys_generic.c Cover a race between doselwakeup() and selfdfree(). If doselwakeup() 2015-07-09 09:22:21 +00:00
sys_pipe.c Make pipes in CloudABI work. 2015-07-29 17:18:27 +00:00
sys_procdesc.c The si_status field of the siginfo_t, provided by the waitid(2) and 2015-07-18 09:02:50 +00:00
sys_process.c Add helper functions proc_readmem() and proc_writemem(). 2015-12-07 21:33:15 +00:00
sys_socket.c In preparation of merging projects/sendfile, transform bare access to 2014-11-12 09:57:15 +00:00
syscalls.c Missing regen after last change to sys/kern/syscalls.master. 2015-10-22 21:30:39 +00:00
syscalls.master Regenerate syscalls. 2015-07-11 15:22:11 +00:00
systrace_args.c Regenerate syscalls. 2015-07-11 15:22:11 +00:00
sysv_ipc.c
sysv_msg.c Add kern.racct.enable tunable and RACCT_DISABLED config option. 2015-04-29 10:23:02 +00:00
sysv_sem.c Add kern.racct.enable tunable and RACCT_DISABLED config option. 2015-04-29 10:23:02 +00:00
sysv_shm.c Change the default setting of kern.ipc.shm_allow_removed from 0 to 1. 2015-10-10 09:29:47 +00:00
tty_compat.c
tty_info.c
tty_inq.c
tty_outq.c
tty_pts.c Implement lockless resource limits. 2015-06-10 10:48:12 +00:00
tty_tty.c tty: replace several curthread->td_proc with stored curproc 2015-07-06 18:53:56 +00:00
tty_ttydisc.c
tty.c filedesc: simplify fget_unlocked & friends 2015-02-17 23:54:06 +00:00
uipc_accf.c The accept filter code is not specific to the FreeBSD IPv4 network stack, 2014-07-26 19:27:34 +00:00
uipc_debug.c Fix sb_state constant names as used e.g. to display in DDB ``show sockbuf''. 2015-07-21 09:57:13 +00:00
uipc_domain.c CALLOUT_MPSAFE has lost its meaning since r141428, i.e., for more than ten 2015-05-22 17:05:21 +00:00
uipc_mbuf2.c Add const-qualifiers for source mbuf argument in m_dup(), m_copym(), 2015-08-08 15:50:46 +00:00
uipc_mbuf.c There are times when it would be really nice to have a record of the last few 2015-10-14 00:35:37 +00:00
uipc_mbufhash.c Reduce header pollution. 2015-03-17 14:16:50 +00:00
uipc_mqueue.c fd: remove filedesc argument from fdclose 2015-04-11 15:40:28 +00:00
uipc_sem.c Call ksem_get() with initialized 'rights'. 2015-07-23 23:18:03 +00:00
uipc_shm.c A change to KPI of vm_pager_get_pages() and underlying VOP_GETPAGES(). 2015-12-16 21:30:45 +00:00
uipc_sockbuf.c Implement lockless resource limits. 2015-06-10 10:48:12 +00:00
uipc_socket.c Make shutdown() return ENOTCONN as required by POSIX, part deux. 2015-07-27 13:17:57 +00:00
uipc_syscalls.c A change to KPI of vm_pager_get_pages() and underlying VOP_GETPAGES(). 2015-12-16 21:30:45 +00:00
uipc_usrreq.c fd: make the common case in filecaps_copy work lockless 2015-09-07 20:02:56 +00:00
vfs_acl.c Replace struct filedesc argument in getvnode with struct thread 2015-06-16 13:09:18 +00:00
vfs_aio.c The aio_waitcomplete(2) syscall should not sleep when the given timeout 2015-10-25 18:48:09 +00:00
vfs_bio.c Don't call wakeup if we're just returning reserved space; just 2015-12-16 00:13:16 +00:00
vfs_cache.c Fix style issues around existing SDT probes. 2015-12-16 23:39:27 +00:00
vfs_cluster.c Refactor unmapped buffer address handling. 2015-07-23 19:13:41 +00:00
vfs_default.c A change to KPI of vm_pager_get_pages() and underlying VOP_GETPAGES(). 2015-12-16 21:30:45 +00:00
vfs_export.c After the changes in r274118 make NOIP kernels compile by hiding an 2014-11-06 12:19:39 +00:00
vfs_extattr.c Replace struct filedesc argument in getvnode with struct thread 2015-06-16 13:09:18 +00:00
vfs_hash.c Track changes to kern.maxvnodes and appropriately increase or decrease 2015-09-06 05:50:51 +00:00
vfs_init.c sysctl: switch sysctllock to a sleepable rmlock, take 2 2015-09-15 23:06:56 +00:00
vfs_lookup.c save some bytes by using more concise SDT_PROBE<n> instead of SDT_PROBE 2015-09-28 12:14:16 +00:00
vfs_mount.c Make vfs_unmountall() unmount /dev after /, not before. The only 2015-08-24 13:18:13 +00:00
vfs_mountroot.c After r290196, the kernel won't wait for stuff like gmirror nodes 2015-10-30 15:52:10 +00:00
vfs_subr.c Optimize vop_stdadvise(POSIX_FADV_DONTNEED). Instead of looking up a 2015-12-16 08:48:37 +00:00
vfs_syscalls.c The freebsd4_getfsstat() was broken in r281551 to always return 0 on success. 2015-11-20 14:08:12 +00:00
vfs_vnops.c Fix r283998 that broke mapin events for hwpmc. 2015-10-08 09:54:33 +00:00
vnode_if.src A change to KPI of vm_pager_get_pages() and underlying VOP_GETPAGES(). 2015-12-16 21:30:45 +00:00