Many changes, mostly backported from 2.5 by Ben LaHaise and
fixed up a bit more by myself. It all appears to work, but
more testing is appropriate.
The second maintenance release of the 15th version of the reverse
mapping based VM is now available.
This is an attempt at making a more robust and flexible VM
subsystem, while cleaning up a lot of code at the same time.
The patch is available from:
http://surriel.com/patches/2.4/2.4.20-rmap15b
and http://linuxvm.bkbits.net/
My big TODO items for a next release are:
- finetune the O(1) VM code for strange corner cases
rmap 15b:
- adjust anon/cache work table (me)
- make active_age_bias a per-active list thing (me)
- don't wake up kswapd early from mark_page_accessed (me)
- make sure pte-chains are cacheline aligned with PAE (me, Andrew Morton)
- change some O(1) VM thresholds (me)
- fix pte-highmem backport (me)
- 2.5 backport: pte-highmem (Ben LaHaise)
- 2.5 backport: large cacheline aligned pte-chains (Ben LaHaise)
- 2.5 backport: direct pte pointers (Ben LaHaise)
- undo __find_pagecache_page braindamage (Christoph Hellwig)
rmap 15a:
- more agressive freeing for higher order allocations (me)
- export __find_pagecache_page, find_get_page define (me, Christoph, Arjan)
- make memory statistics SMP safe again (me)
- make page aging slow down again when needed (Andrew Morton)
- first stab at fine-tuning arjan's O(1) VM (me)
- split active list in cache / working set (me)
- fix SMP locking in arjan's O(1) VM (me)
rmap 15:
- small code cleanups and spelling fixes for O(1) VM (me)
- O(1) page launder, O(1) page aging (Arjan van de Ven)
- resync code with -ac (12 small patches) (me)
rmap 14c:
- fold page_over_rsslimit() into page_referenced() (me)
- 2.5 backport: get pte_chains from the slab cache (William Lee Irwin)
- remove dead code from page_launder_zone() (me)
- make OOM detection a bit more agressive (me)
rmap 14b:
- don't unmap pages not in pagecache (ext3 & reiser) (Andrew Morton, me)
- clean up mark_page_accessed a bit (me)
- Alpha NUMA fix for Ingo's per-cpu pages (Fl?vio Leitner, me)
- remove explicit low latency schedule zap_page_range (Robert Love)
- fix OOM stuff for good, hopefully (me)
rmap 14a:
- Ingo Molnar's per-cpu pages (SMP speedup) (Christoph Hellwig)
- fix SMP bug in page_launder_zone (rmap14 only) (Arjan van de Ven)
- semicolon day, fix typo in rmap.c w/ DEBUG_RMAP (Craig Kulesa)
- remove unneeded pte_chain_unlock/lock pair vmscan.c (Craig Kulesa)
- low latency zap_page_range also without preempt (Arjan van de Ven)
- do some throughput tuning for kswapd/page_launder (me)
- don't allocate swap space for pages we're not writing (me)
rmap 14:
- get rid of stalls during swapping, hopefully (me)
- low latency zap_page_range (Robert Love)
rmap 13c:
- add wmb() to wakeup_memwaiters (Arjan van de Ven)
- remap_pmd_range now calls pte_alloc with full address (Paul Mackerras)
- #ifdef out pte_chain_lock/unlock on UP machines (Andrew Morton)
- un-BUG() truncate_complete_page, the race is expected (Andrew Morton, me)
- remove NUMA changes from rmap13a (Christoph Hellwig)
rmap 13b:
- prevent PF_MEMALLOC recursion for higher order allocs (Arjan van de Ven, me)
- fix small SMP race, PG_lru (Hugh Dickins)
rmap 13a:
- NUMA changes for page_address (Samuel Ortiz)
- replace vm.freepages with simpler kswapd_minfree (Christoph Hellwig)
rmap 13:
- rename touch_page to mark_page_accessed and uninline (Christoph Hellwig)
- NUMA bugfix for __alloc_pages (William Irwin)
- kill __find_page (Christoph Hellwig)
- make pte_chain_freelist per zone (William Irwin)
- protect pte_chains by per-page lock bit (William Irwin)
- minor code cleanups (me)
rmap 12i:
- slab cleanup (Christoph Hellwig)
- remove references to compiler.h from mm/* (me)
- move rmap to marcelo's bk tree (me)
- minor cleanups (me)
rmap 12h:
- hopefully fix OOM detection algorithm (me)
- drop pte quicklist in anticipation of pte-highmem (me)
- replace andrea's highmem emulation by ingo's one (me)
- improve rss limit checking (Nick Piggin)
rmap 12g:
- port to armv architecture (David Woodhouse)
- NUMA fix to zone_table initialisation (Samuel Ortiz)
- remove init_page_count (David Miller)
rmap 12f:
- for_each_pgdat macro (William Lee Irwin)
- put back EXPORT(__find_get_page) for modular rd (me)
- make bdflush and kswapd actually start queued disk IO (me)
rmap 12e
- RSS limit fix, the limit can be 0 for some reason (me)
- clean up for_each_zone define to not need pgdata_t (William Lee Irwin)
- fix i810_dma bug introduced with page->wait removal (William Lee Irwin)
rmap 12d:
- fix compiler warning in rmap.c (Roger Larsson)
- read latency improvement (read-latency2) (Andrew Morton)
rmap 12c:
- fix small balancing bug in page_launder_zone (Nick Piggin)
- wakeup_kswapd / wakeup_memwaiters code fix (Arjan van de Ven)
- improve RSS limit enforcement (me)
rmap 12b:
- highmem emulation (for debugging purposes) (Andrea Arcangeli)
- ulimit RSS enforcement when memory gets tight (me)
- sparc64 page->virtual quickfix (Greg Procunier)
rmap 12a:
- fix the compile warning in buffer.c (me)
- fix divide-by-zero on highmem initialisation DOH! (me)
- remove the pgd quicklist (suspicious ...) (DaveM, me)
rmap 12:
- keep some extra free memory on large machines (Arjan van de Ven, me)
- higher-order allocation bugfix (Adrian Drzewiecki)
- nr_free_buffer_pages() returns inactive + free mem (me)
- pages from unused objects directly to inactive_clean (me)
- use fast pte quicklists on non-pae machines (Andrea Arcangeli)
- remove sleep_on from wakeup_kswapd (Arjan van de Ven)
- page waitqueue cleanup (Christoph Hellwig)
rmap 11c:
- oom_kill race locking fix (Andres Salomon)
- elevator improvement (Andrew Morton)
- dirty buffer writeout speedup (hopefully ;)) (me)
- small documentation updates (me)
- page_launder() never does synchronous IO, kswapd
and the processes calling it sleep on higher level (me)
- deadlock fix in touch_page() (me)
rmap 11b:
- added low latency reschedule points in vmscan.c (me)
- make i810_dma.c include mm_inline.h too (William Lee Irwin)
- wake up kswapd sleeper tasks on OOM kill so the
killed task can continue on its way out (me)
- tune page allocation sleep point a little (me)
rmap 11a:
- don't let refill_inactive() progress count for OOM (me)
- after an OOM kill, wait 5 seconds for the next kill (me)
- agpgart_be fix for hashed waitqueues (William Lee Irwin)
rmap 11:
- fix stupid logic inversion bug in wakeup_kswapd() (Andrew Morton)
- fix it again in the morning (me)
- add #ifdef BROKEN_PPC_PTE_ALLOC_ONE to rmap.h, it
seems PPC calls pte_alloc() before mem_map[] init (me)
- disable the debugging code in rmap.c ... the code
is working and people are running benchmarks (me)
- let the slab cache shrink functions return a value
to help prevent early OOM killing (Ed Tomlinson)
- also, don't call the OOM code if we have enough
free pages (me)
- move the call to lru_cache_del into __free_pages_ok (Ben LaHaise)
- replace the per-page waitqueue with a hashed
waitqueue, reduces size of struct page from 64
bytes to 52 bytes (48 bytes on non-highmem machines) (William Lee Irwin)
rmap 10:
- fix the livelock for real (yeah right), turned out
to be a stupid bug in page_launder_zone() (me)
- to make sure the VM subsystem doesn't monopolise
the CPU, let kswapd and some apps sleep a bit under
heavy stress situations (me)
- let __GFP_HIGH allocations dig a little bit deeper
into the free page pool, the SCSI layer seems fragile (me)
rmap 9:
- improve comments all over the place (Michael Cohen)
- don't panic if page_remove_rmap() cannot find the
rmap in question, it's possible that the memory was
PG_reserved and belonging to a driver, but the driver
exited and cleared the PG_reserved bit (me)
- fix the VM livelock by replacing > by >= in a few
critical places in the pageout code (me)
- treat the reclaiming of an inactive_clean page like
allocating a new page, calling try_to_free_pages()
and/or fixup_freespace() if required (me)
- when low on memory, don't make things worse by
doing swapin_readahead (me)
rmap 8:
- add ANY_ZONE to the balancing functions to improve
kswapd's balancing a bit (me)
- regularize some of the maximum loop bounds in
vmscan.c for cosmetic purposes (William Lee Irwin)
- move page_address() to architecture-independent
code, now the removal of page->virtual is portable (William Lee Irwin)
- speed up free_area_init_core() by doing a single
pass over the pages and not using atomic ops (William Lee Irwin)
- documented the buddy allocator in page_alloc.c (William Lee Irwin)
rmap 7:
- clean up and document vmscan.c (me)
- reduce size of page struct, part one (William Lee Irwin)
- add rmap.h for other archs (untested, not for ARM) (me)
rmap 6:
- make the active and inactive_dirty list per zone,
this is finally possible because we can free pages
based on their physical address (William Lee Irwin)
- cleaned up William's code a bit (me)
- turn some defines into inlines and move those to
mm_inline.h (the includes are a mess ...) (me)
- improve the VM balancing a bit (me)
- add back inactive_target to /proc/meminfo (me)
rmap 5:
- fixed recursive buglet, introduced by directly
editing the patch for making rmap 4 ;))) (me)
rmap 4:
- look at the referenced bits in page tables (me)
rmap 3:
- forgot one FASTCALL definition (me)
rmap 2:
- teach try_to_unmap_one() about mremap() (me)
- don't assign swap space to pages with buffers (me)
- make the rmap.c functions FASTCALL / inline (me)
rmap 1:
- fix the swap leak in rmap 0 (Dave McCracken)
rmap 0:
- port of reverse mapping VM to 2.4.16 (me)
Rik
--
Bravely reimplemented by the knights who say "NIH".
http://www.surriel.com/ http://guru.conectiva.com/
Current spamtrap: <a href=mailto:"[email protected]">[email protected]</a>
Rik van Riel wrote:
> The patch is available from:
>
> http://surriel.com/patches/2.4/2.4.20-rmap15b
Again the patch is against -rc4 so a Makefile hunk fails. Not
a real problem.
--
Eyal Lebedinsky ([email protected]) <http://samba.org/eyal/>
On Tue, 17 Dec 2002 19:50:04 -0200 (BRST)
Rik van Riel <[email protected]> wrote:
> On Mon, 16 Dec 2002, Georg Nikodym wrote:
>
> > Incidentally, a colleague claimed to have seem this behaviour on a
> > non-rmap 2.4.20.
>
> > 1. Known behaviour?
> > 2. Is there any data that I should be collecting that people are
> > interested in?
> > 3. Or should I just go back to 2.4.19-rmap14b (which did not trouble
> > me
> > in this way)?
>
> The suspect is the disk elevator, which isn't scheduling requests
> in a way to cause lower read latency, but is optimised more for
> throughput. This results in some pauses.
>
> I'll need to look into it.
I discovered after sending the above:
Dec 16 15:08:04 keller kernel: ieee1394: sbp2: sbp2util_allocate_request_packet
- no packets available!
Dec 16 15:08:04 keller kernel: ieee1394: sbp2: sbp2util_allocate_write_request_p
acket failed
Dec 16 15:08:34 keller kernel: ieee1394: sbp2: aborting sbp2 command
These messages correspond with the pauses... However, the ieee1394 code
has not changed in some time (as in many months).
-g
On Mon, 16 Dec 2002, Georg Nikodym wrote:
> Incidentally, a colleague claimed to have seem this behaviour on a
> non-rmap 2.4.20.
> 1. Known behaviour?
> 2. Is there any data that I should be collecting that people are
> interested in?
> 3. Or should I just go back to 2.4.19-rmap14b (which did not trouble me
> in this way)?
The suspect is the disk elevator, which isn't scheduling requests
in a way to cause lower read latency, but is optimised more for
throughput. This results in some pauses.
I'll need to look into it.
regards,
Rik
--
Bravely reimplemented by the knights who say "NIH".
http://www.surriel.com/ http://guru.conectiva.com/
Current spamtrap: <a href=mailto:"[email protected]">[email protected]</a>