Several patches here which fix pretty much the last source of long
scheduling latency stalls in the core kernel - long-held page_table_lock
during pagetable teardown.
The preemptible kernel now achieves around 500 microsecond worst-case
latency on a 500MHz PIII (with a slow memory system). This is about as
good as the 2.4 low-latency patch. Maybe better.
This is with ext2, and only with ext2. Other filesystems need work
to reach that level of performance.
Non-preemptible kernels will benefit as well. This sort of means that
preemptibility is only really needed for specialised multimedia/control
type apps. Opinions vary ;)
Filesystem mount and unmount is a problem. Probably, this will not be
addressed. People who have specialised latency requirements should avoid
using automounters and those gadgets which poll CDROMs for insertion events.
This work has broken the shared pagetable patch - it touches the same code
in many places. I shall put Humpty together again, but will not be
including it for some time. This is because there may be bugs in this
patch series which are accidentally fixed in the shared pagetable patch. So
shared pagetables will be reintegrated when these changes have had sufficient
testing.
Hugh, could you please closely review these changes sometime? Thanks.
Changes since 2.4.54-mm2:
-no-stem-compression.patch
It got fixed.
+linus.patch
latest drop from Linus
+devfs-mount-fix.patch
Fix a problem with mounting a devfs=y system with root=<number>
+nfsd-fix.patch
Fix a knfsd problem
+3c920.patch
3c920 support for 3c59x.c
-shpte-ng.patch
See above
+untypedef-mmu_gather.patch
Replace the mmu_gather_t typedef with `struct mmu_gather'.
+low-latency-page-unmapping.patch
Fix long-held spinlocks in exit_mmap() and unmap_region()
+smp-preempt-latency-fix.patch
Fix a cross-cpu problem which causes long scheduling stalls
on SMP+preempt
-#smaller-head-arrays.patch
+smaller-head-arrays.patch
I really do think those slab head arrays are too big.
-fix-ethernet-hash.patch
Jeff merged a fix
All 70 patches:
linus.patch
cset-1.930.1.15-to-1.977.txt.gz
kgdb.patch
log_buf_size.patch
move LOG_BUF_SIZE to header/config
nfsd-fix.patch
Subject: Re: nfsd woes
rcf.patch
run-child-first after fork
devfs-fix.patch
devfs-mount-fix.patch
devfs mount-time readdir fix and cleanup
dio-return-partial-result.patch
aio-direct-io-infrastructure.patch
AIO support for raw/O_DIRECT
deferred-bio-dirtying.patch
bio dirtying infrastructure
aio-direct-io.patch
AIO support for raw/O_DIRECT
aio-dio-debug.patch
dio-reduce-context-switch-rate.patch
Reduced wakeup rate in direct-io code
cputimes_stat.patch
Retore per-cpu time accounting, with a config option
misc.patch
misc fixes
3c920.patch
3c59x: 3c920 support
inlines-net.patch
rbtree-iosched.patch
rbtree-based IO scheduler
deadsched-fix.patch
deadline scheduler fix
copy_page_range-cleanup.patch
copy_page_range: minor cleanup
pte_chain_alloc-fix.patch
infrastructure for handling pte_chain_alloc() failures
page_add_rmap-rework.patch
handle fix pte_chain_alloc() failures
rat-preload.patch
infrastructure for handling radix_tree_node allocation failures
use-rat-preallocation.patch
handle radix_tree_node allocation failures
i_shared_sem.patch
turn i_shared_lock into a semaphore
cond_resched_lock-rework.patch
simplify and generalise cond_resched_lock
untypedef-mmu_gather.patch
replace `typedef mmu_gather_t' with `struct mmu_gather'
low-latency-page-unmapping.patch
low-latency pagetable teardown
smp-preempt-latency-fix.patch
Fix an SMP+preempt latency problem
smaller-head-arrays.patch
mempool_resize-fix.patch
mempool_resize fix
slab-redzone-cleanup.patch
slab: redzoning cleanup
shrink-kmap-space.patch
shrink the amount of vmalloc space reserved for kmap
setuid-exec-no-lock_kernel.patch
remove lock_kernel() from exec of setuid apps
ptrace-flush.patch
Subject: [PATCH] ptrace on 2.5.44
buffer-debug.patch
buffer.c debugging
warn-null-wakeup.patch
pentium-II.patch
Pentium-II support bits
rcu-stats.patch
RCU statistics reporting
auto-unplug.patch
self-unplugging request queues
less-unplugging.patch
Remove most of the blk_run_queues() calls
ext3-fsync-speedup.patch
Clean up ext3_sync_file()
lockless-current_kernel_time.patch
Lockless current_kernel_timer()
scheduler-tunables.patch
scheduler tunables
dio-always-kmalloc.patch
direct-io: dynamically allocate struct dio
set_page_dirty_lock.patch
fix set_page_dirty vs truncate&free races
htlb-2.patch
hugetlb: fix MAP_FIXED handling
route-cache-kmalloc-per-cpu.patch
use kmalloc-per-cpu for the routecache stats
wli-01_numaq_io.patch
(undescribed patch)
wli-02_do_sak.patch
(undescribed patch)
wli-03_proc_super.patch
(undescribed patch)
wli-06_uml_get_task.patch
(undescribed patch)
wli-07_numaq_mem_map.patch
(undescribed patch)
wli-08_numaq_pgdat.patch
(undescribed patch)
wli-09_has_stopped_jobs.patch
(undescribed patch)
wli-10_inode_wait.patch
(undescribed patch)
wli-11_pgd_ctor.patch
(undescribed patch)
wli-11_pgd_ctor-update.patch
pgd_ctor update
wli-12_pidhash_size.patch
Dynamically size the pidhash hash table.
wli-13_rmap_nrpte.patch
(undescribed patch)
dcache_rcu-2.patch
dcache_rcu-2-2.5.51.patch
dcache_rcu-3.patch
dcache_rcu-3-2.5.51.patch
page-walk-api.patch
page-walk-api-2.5.53-mm2-update.patch
pagewalk API update
page-walk-scsi.patch
page-walk-scsi-2.5.53-mm2.patch
pagewalk scsi update
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