- 03 Jan, 2005 26 commits
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Brent Casavant authored
Modifies the TCP ehash and TCP bhash to enable the use of vmalloc to alleviate boottime memory allocation imbalances on NUMA systems, utilizing flags to the alloc_large_system_hash routine in order to centralize the enabling of this behavior. Signed-off-by:
Brent Casavant <bcasavan@sgi.com> Signed-off-by:
Andrew Morton <akpm@osdl.org> Signed-off-by:
Linus Torvalds <torvalds@osdl.org>
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Brent Casavant authored
The following patch modifies the dentry cache and inode cache to enable the use of vmalloc to alleviate boottime memory allocation imbalances on NUMA systems, utilizing flags to the alloc_large_system_hash routine in order to centralize the enabling of this behavior. In general, for each hash, we check at the early allocation point whether hash distribution is enabled, and if so we defer allocation. At the late allocation point we perform the allocation if it was not earlier deferred. These late allocation points are the same points utilized prior to the addition of alloc_large_system_hash to the kernel. Signed-off-by:
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Brent Casavant authored
NUMA systems running current Linux kernels suffer from substantial inequities in the amount of memory allocated from each NUMA node during boot. In particular, several large hashes are allocated using alloc_bootmem, and as such are allocated contiguously from a single node each. This becomes a problem for certain workloads that are relatively common on big-iron HPC NUMA systems. In particular, a number of MPI and OpenMP applications which require nearly all available processors in the system and nearly all the memory on each node run into difficulties. Due to the uneven memory distribution onto a few nodes, any thread on those nodes will require a portion of its memory be allocated from remote nodes. Any access to those memory locations will be slower than local accesses, and thereby slows down the effective computation rate for the affected CPUs/threads. This problem is further amplified if the application is tightly synchronized between threads (as is often the case), as they entire job can run only at the speed of the slowest thread. Additionally since these hashes are usually accessed by all CPUS in the system, the NUMA network link on the node which hosts the hash experiences disproportionate traffic levels, thereby reducing the memory bandwidth available to that node's CPUs, and further penalizing performance of the threads executed thereupon. As such, it is desired to find a way to distribute these large hash allocations more evenly across NUMA nodes. Fortunately current kernels do perform allocation interleaving for vmalloc() during boot, which provides a stepping stone to a solution. This series of patches enables (but does not require) the kernel to allocate several boot time hashes using vmalloc rather than alloc_bootmem, thereby causing the hashes to be interleaved amongst NUMA nodes. In particular the dentry cache, inode cache, TCP ehash, and TCP bhash have been changed to be allocated in this manner. Due to the limited vmalloc space on architectures such as i386, this behavior is turned on by default only for IA64 NUMA systems (though there is no reason other interested architectures could not enable it if desired). Non-IA64 and non-NUMA systems continue to use the existing alloc_bootmem() allocation mechanism. A boot line parameter "hashdist" can be set to override the default behavior. The following two sets of example output show the uneven distribution just after boot, using init=/bin/sh to eliminate as much non-kernel allocation as possible. Without the boot hash distribution patches: Nid MemTotal MemFree MemUsed (in kB) 0 3870656 3697696 172960 1 3882992 3866656 16336 2 3883008 3866784 16224 3 3882992 3866464 16528 4 3883008 3866592 16416 5 3883008 3866720 16288 6 3882992 3342176 540816 7 3883008 3865440 17568 8 3882992 3866560 16432 9 3883008 3866400 16608 10 3882992 3866592 16400 11 3883008 3866400 16608 12 3882992 3866400 16592 13 3883008 3866432 16576 14 3883008 3866528 16480 15 3864768 3848256 16512 ToT 62097440 61152096 945344 Notice that nodes 0 and 6 have a substantially larger memory utilization than all other nodes. With the boot hash distribution patch: Nid MemTotal MemFree MemUsed (in kB) 0 3870656 3789792 80864 1 3882992 3843776 39216 2 3883008 3843808 39200 3 3882992 3843904 39088 4 3883008 3827488 55520 5 3883008 3843712 39296 6 3882992 3843936 39056 7 3883008 3844096 38912 8 3882992 3843712 39280 9 3883008 3844000 39008 10 3882992 3843872 39120 11 3883008 3843872 39136 12 3882992 3843808 39184 13 3883008 3843936 39072 14 3883008 3843712 39296 15 3864768 3825760 39008 ToT 62097440 61413184 684256 While not perfectly even, we can see that there is a substantial improvement in the spread of memory allocated by the kernel during boot. The remaining uneveness may be due in part to further boot time allocations that could be addressed in a similar manner, but some difference is due to the somewhat special nature of node 0 during boot. However the uneveness has fallen to a much more acceptable level (at least to a level that SGI isn't concerned about). The astute reader will also notice that in this example, with this patch approximately 256 MB less memory was allocated during boot. This is due to the size limits of a single vmalloc. More specifically, this is because the automatically computed size of the TCP ehash exceeds the maximum size which a single vmalloc can accomodate. However this is of little practical concern as the vmalloc size limit simply reduces one ridiculously large allocation (512MB) to a slightly less ridiculously large allocation (256MB). In practice machines with large memory configurations are using the thash_entries setting to limit the size of the TCP ehash _much_ lower than either of the automatically computed values. Illustrative of the exceedingly large nature of the automatically computed size, SGI currently recommends that customers boot with thash_entries=2097152, which works out to a 32MB allocation. In any case, setting hashdist=0 will allow for allocations in excess of vmalloc limits, if so desired. Other than the vmalloc limit, great care was taken to ensure that the size of TCP hash allocations was not altered by this patch. Due to slightly different computation techniques between the existing TCP code and alloc_large_system_hash (which is now utilized), some of the magic constants in the TCP hash allocation code were changed. On all sizes of system (128MB through 64GB) that I had access to, the patched code preserves the previous hash size, as long as the vmalloc limit (256MB on IA64) is not encountered. There was concern that changing the TCP-related hashes to use vmalloc space may adversely impact network performance. To this end the netperf set of benchmarks was run. Some individual tests seemed to benefit slightly, some seemed to be harmed slightly, but in all cases the average difference with and without these patches was well within the variabilty I would see from run to run. The following is the overall netperf averages (30 10 second runs each) against an older kernel with these same patches. These tests were run over loopback as GigE results were so inconsistent run to run both with and without these patches that they provided no meaningful comparison that I could discern. I used the same kernel (IA64 generic) for each run, simply varying the new "hashdist" boot parameter to turn on or off the new allocation behavior. In all cases the thash_entries value was manually specified as discussed previously to eliminate any variability that might result from that size difference. HP ZX1, hashdist=0 ================== TCP_RR = 19389 TCP_MAERTS = 6561 TCP_STREAM = 6590 TCP_CC = 9483 TCP_CRR = 8633 HP ZX1, hashdist=1 ================== TCP_RR = 19411 TCP_MAERTS = 6559 TCP_STREAM = 6584 TCP_CC = 9454 TCP_CRR = 8626 SGI Altix, hashdist=0 ===================== TCP_RR = 16871 TCP_MAERTS = 3925 TCP_STREAM = 4055 TCP_CC = 8438 TCP_CRR = 7750 SGI Altix, hashdist=1 ===================== TCP_RR = 17040 TCP_MAERTS = 3913 TCP_STREAM = 4044 TCP_CC = 8367 TCP_CRR = 7538 I believe the TCP_CC and TCP_CRR are the tests most sensitive to this particular change. But again, I want to emphasize that even the differences you see above are _well_ within the variability I saw from run to run of any given test. In addition, Jose Santos at IBM has run specSFS, which has been particularly sensitive to TLB issues, against these patches and saw no performance degredation (differences down in the noise). This patch: Modifies alloc_large_system_hash to enable the use of vmalloc to alleviate boottime allocation imbalances on NUMA systems. Due to limited vmalloc space on some architectures (i.e. x86), the use of vmalloc is enabled by default only on NUMA IA64 kernels. There should be no problem enabling this change for any other interested NUMA architecture. Signed-off-by:
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Alex Williamson authored
I noticed the function __read_page_state() curiously high in a q-tools profile of a write to a software raid0 device. Seems this is because we're checking page_states for all possible cpus and we have NR_CPUS possible when CONFIG_HOTPLUG_CPU=y. The default config for ia64 is now NR_CPUS=512, so on a little 8-way box, this is a significant waste of time. The patch below updates __read_page_state() and __get_page_state() to only count page_state info for online cpus. To keep the stats consistent, the page_alloc notifier is updated to move page_states off of the cpu going offline. On my profile, this dropped __read_page_state() back into the noise and boosted block write performance by 5% (as measured by spew - http://spew.berlios.de). Signed-off-by:
Alex Williamson <alex.williamson@hp.com> Signed-off-by:
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Manfred Spraul authored
Add ARCH_SLAB_MINALIGN and document ARCH_KMALLOC_MINALIGN: The flags allow the arch code to override the default minimum object aligment (BYTES_PER_WORD). Signed-Off-By:
Manfred Spraul <manfred@colorfullife.com> Signed-off-by:
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Andrew Morton authored
mark_page_accessed() is more heavyweight than we need: the page is already headed for the active list, so setting the software-referenced bit is equivalent. Signed-off-by:
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Miquel van Smoorenburg authored
When reading a (partial) page from disk using read(), the kernel only marks the page as "accessed" if the read started at a page boundary. This means that files that are accessed randomly at non-page boundaries (usually database style files) will not be cached properly. The patch below uses the readahead state instead. If a page is read(), it is marked as "accessed" if the previous read() was for a different page, whatever the offset in the page. Testing results: - Boot kernel with mem=128M - create a testfile of size 8 MB on a partition. Unmount/mount. - then generate about 10 MB/sec streaming writes for i in `seq 1 1000` do dd if=/dev/zero of=junkfile.$i bs=1M count=10 sync cat junkfile.$i > /dev/null sleep 1 done - use an application that reads 128 bytes 64000 times from a random offset in the 64 MB testfile. 1. Linux 2.6.10-rc3 vanilla, no streaming writes: # time ~/rr testfile Read 128 bytes 64000 times ~/rr testfile 0.03s user 0.22s system 5% cpu 4.456 total 2. Linux 2.6.10-rc3 vanilla, streaming writes: # time ~/rr testfile Read 128 bytes 64000 times ~/rr testfile 0.03s user 0.16s system 2% cpu 7.667 total # time ~/rr testfile Read 128 bytes 64000 times ~/rr testfile 0.03s user 0.37s system 1% cpu 23.294 total # time ~/rr testfile Read 128 bytes 64000 times ~/rr testfile 0.02s user 0.99s system 1% cpu 1:11.52 total # time ~/rr testfile Read 128 bytes 64000 times ~/rr testfile 0.03s user 0.21s system 2% cpu 10.273 total 3. Linux 2.6.10-rc3 with read-page-access.patch , streaming writes: # time ~/rr testfile Read 128 bytes 64000 times ~/rr testfile 0.02s user 0.21s system 3% cpu 7.634 total # time ~/rr testfile Read 128 bytes 64000 times ~/rr testfile 0.04s user 0.22s system 2% cpu 9.588 total # time ~/rr testfile Read 128 bytes 64000 times ~/rr testfile 0.02s user 0.12s system 24% cpu 0.563 total # time ~/rr testfile Read 128 bytes 64000 times ~/rr testfile 0.03s user 0.13s system 98% cpu 0.163 total As expected, with the read-page-access.patch, the kernel keeps the 8 MB testfile cached as expected, while without it, it doesn't. So this is useful for workloads where one smallish (wrt RAM) file is read randomly over and over again (like heavily used database indexes), while other I/O is going on. Plain 2.6 caches those files poorly, if the app uses plain read(). Signed-Off-By:
Miquel van Smoorenburg <miquels@cistron.nl> Signed-off-by:
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Dave Hansen authored
When CONFIG_HIGHMEM=y, but ZONE_NORMAL isn't quite full, there is, of course, no actual memory at *high_memory. This isn't a problem with normal virt<->phys translations because it's never dereferenced, but CONFIG_NONLINEAR is a bit more finicky. So, don't do virt_to_phys() to non-existent addresses. Signed-off-by:
Dave Hansen <haveblue@us.ibm.com> Signed-off-by:
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Dave Hansen authored
People love to do comparisons with highmem_start_page. However, where CONFIG_HIGHMEM=y and there is no actual highmem, there's no real page at *highmem_start_page. That's usually not a problem, but CONFIG_NONLINEAR is a bit more strict and catches the bogus address tranlations. There are about a gillion different ways to find out of a 'struct page' is highmem or not. Why not just check page_flags? Just use PageHighMem() wherever there used to be a highmem_start_page comparison. Then, kill off highmem_start_page. This removes more code than it adds, and gets rid of some nasty #ifdefs in .c files. Signed-off-by:
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Andries E. Brouwer authored
Alan made overcommit mode 2 and it doesnt work at all. A process passing the limit often does so at a moment of stack extension, and is killed by a segfault, not better than being OOM-killed. Another problem is that close to the edge no other processes can be started, so that a sysadmin has problems logging in and investigating. Below a patch that does 3 things: (1) It reserves a reasonable amount of virtual stack space (amount randomly chosen, no guarantees given) when the process is started, so that the common utilities will not be killed by segfault on stack extension. (2) It reserves a reasonable amount of virtual memory for root, so that root can do things when the system is out-of-memory (3) It limits a single process to 97% of what is left, so that also an ordinary user is able to use getty, login, bash, ps, kill and similar things when one of her processes got out of control. Since the current overcommit mode 2 is not really useful, I did not give this a new number. The patch is just for playing, not to be applied by Linus. But, Andrew, I hope that you would be willing to put this in -mm so that people can experiment. Of course it only does something if one sets overcommit mode to 2. The past month I have pressured people asking for feedback, and now have about a dozen reports, mostly positive, one very positive. Signed-off-by: -
Andrea Arcangeli authored
Some optimizations in mempolicy.c (like to avoid rebalancing the tree while destroying it and by breaking loops early and not checking for invariant conditions in the replace operation). Signed-off-by:
Andrea Arcangeli <andrea@novell.com> Signed-off-by:
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Ram Pai authored
Reinstate the feature wherein readahead will be bypassed if the underlying queue is read-congersted. Signed-off-by:
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Steven Pratt authored
With Ram Pai <linuxram@us.ibm.com> - request size is now passed into page_cache_readahead. This allows the removal of the size averaging code in the current readahead logic. - readahead rampup is now faster (especially for larger request sizes) - No longer "slow read path". Readahead is turn off at first random access, turned back on at first sequential access. - Code now handles thrashing, slowly reducing readahead window until thrashing stops, or min size reached. - Returned to old behavior where first access is assumed sequential only if at offset 0. - designed to handle larger (1M or above) window sizes efficiently Benchmark results: machine 1: 8 way pentiumIV 1GB memory, tests run to 36GB SCSI disk (Similar results were seen on a 1 way 866Mhz box with IDE disk.) TioBench: tiobench.pl --dir /mnt/tmp --block 4096 --size 4000 --numruns 2 --threads 1(4,16,64) 4k request size sequential read results in MB/sec Threads 2.6.9 w/patches %diff diff
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Nick Piggin authored
Teach kswapd to free memory on behalf of higher order allocators. This could be important for higher order atomic allocations because they otherwise have no means to free the memory themselves. Signed-off-by:
Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by:
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Nick Piggin authored
Move the watermark checking code into a single function. Extend it to account for the order of the allocation and the number of free pages that could satisfy such a request. From: Marcelo Tosatti <marcelo.tosatti@cyclades.com> Fix typo in Nick's kswapd-high-order awareness patch Signed-off-by:
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Nick Piggin authored
Keep track of the number of free pages of each order in the buddy allocator. Signed-off-by:
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Ron Murray authored
With Cal Peake <cp@absolutedigital.net> I've found a typo in drivers/input/gameport/Makefile in kernel 2.6.9 which effectively prevents the CS461x gameport code from being included. Signed-off-by:
Ron Murray <rjmx@rjmx.net> Signed-off-by:
Cal Peake <cp@absolutedigital.net> Signed-off-by:
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Andrew Morton authored
We haven't been incrementing local variable total_scanned since the scan_control stuff went in. That broke kswapd throttling. Signed-off-by:
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Jan Kara authored
Allow disabling of quota messages to console (they can disturb other output). Signed-off-by:
Jan Kara <jack@suse.cz> Signed-off-by:
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Jan Kara authored
Implement quota journaling and quota reading and writing functions for reiserfs. Solves also several other deadlocks possible for reiserfs due to the lock inversion on journal_begin and quota locks. From: Vladimir Saveliev <vs@namesys.com> When CONFIG_QUOTA is defined reiserfs's finish_unfinished sets and clears MS_ACTIVE bit in s_flags field of super block. If that bit was set already it should not be set. Signed-off-by:
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Jan Kara authored
Implementation of quota reading and writing functions for ext3. Signed-off-by:
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Jan Kara authored
Implementation of quota reading and writing functions for ext2. Signed-off-by:
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Jan Kara authored
Fix possible races between umount and quota on/off. Finally I decided to take a reference to vfsmount during vfs_quota_on() and to drop it after the final cleanup in the vfs_quota_off(). This way we should be all the time guarded against umount. This way was protected also the old code which used filp_open() for opening quota files. I was also thinking about other ways of protection but there would be always a window (provided I don't want to play much with namespace locks) where vfs_quota_on() could be called while umount() is in progress resulting in the "Busy inodes after unmount" messages... Get a reference to vfsmount during quotaon() so that we are guarded against umount (as was the old code using filp_open()). Signed-off-by:
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Jan Kara authored
The four patches in this series fix deadlocks with quotas of pagelock (the problem was lock inversion on PageLock and transaction start - quota code needed to first start a transaction and then write the data which subsequently needed acquisition of PageLock while the standard ordering - PageLock first and transaction start later - was used e.g. by pdflush). They implement a new way of quota access to disk: Every filesystem that would like to implement quotas now has to provide quota_read() and quota_write() functions. These functions must obey quota lock ordering (in particular they should not take PageLock inside a transaction). The first patch implements the changes in the quota core, the other three patches implement needed functions in ext2, ext3 and reiserfs. The patch for reiserfs also fixes several other lock inversion problems (similar as ext3 had) and implements the journaled quota functionality (which comes almost for free after the locking fixes...). The quota core patch makes quota support in other filesystems (except XFS which implements everything on its own ;)) unfunctional (quotaon() will refuse to turn on quotas on them). When the patches get reasonable wide testing and it will seem that no major changes will be needed I can make fixes also for the other filesystems (JFS, UDF, UFS). This patch: The patch implements the new way of quota io in the quota core. Every filesystem wanting to support quotas has to provide functions quota_read() and quota_write() obeying quota locking rules. As the writes and reads bypass the pagecache there is some ugly stuff ensuring that userspace can see all the data after quotaoff() (or Q_SYNC quotactl). In future I plan to make quota files inaccessible from userspace (with the exception of quotacheck(8) which will take care about the cache flushing and such stuff itself) so that this synchronization stuff can be removed... The rewrite of the quota core. Quota uses the filesystem read() and write() functions no more to avoid possible deadlocks on PageLock. From now on every filesystem supporting quotas must provide functions quota_read() and quota_write() which obey the quota locking rules (e.g. they cannot acquire the PageLock). Signed-off-by:
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Jan Kara authored
Attached patch fixes debug messages of quota code in reiserfs so that they compile. Chris Mason agreed the patch. Signed-off-by:
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Jan Kara authored
Attached patch exposes reiserfs_sync_fs(). This call is needed by the new quota code to write data to disk on quotaoff so that userspace can see them afterwards. Chris Mason agrees with the patch. Make reiserfs provide the sync_fs() function so that the quota code has a way to reliably force a transaction to disk. Signed-off-by:
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- 02 Jan, 2005 14 commits
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Nick Piggin authored
Fix a 4-level page table bug that slipped through (introduced by me, not Andi). Compiles and boots on ia64 and 2-level i386. Signed-off-by:
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Linus Torvalds authored
Pretty much all the TF-related comments were stale, and had been for a long time. Fix them up, clean up code.
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Linus Torvalds authored
PT_DTRACE without PT_PTRACED. Long ago, the "D" in PT_DTRACE meant "Delayed", and it was used as a flag to mark that we had ptrace'd the process but no longer did so. That hasn't been true in a while now, and the flag should probably be renamed, but in the meantime the test for PT_PTRACED being cleared had been corrupted into something totally nonsensical. Pointed out by Andi Kleen.
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bk://bk.arm.linux.org.uk/linux-2.6-mmcLinus Torvalds authored
into ppc970.osdl.org:/home/torvalds/v2.6/linux
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Russell King authored
Quieten down compiler warnings, and fix an off-by-one bug when deciding whether to include the next word.
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bk://bk.arm.linux.org.uk/linux-2.6-rmkLinus Torvalds authored
into ppc970.osdl.org:/home/torvalds/v2.6/linux
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Linus Torvalds authored
It didn't allocate space for the final terminating entry, which caused it to overwrite the next slab entry, which in turn sometimes ended up being a slab array cache pointer. End result: total slab cache corruption at a random time afterwards. Very nasty.
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Alexander Viro authored
some trivial iomem annotations were still missing Signed-off-by:
Al Viro <viro@parcelfarce.linux.theplanet.co.uk> Signed-off-by:
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Alexander Viro authored
local variable used to store flags after spin_lock_irqsave() should be unsigned long, not u32. That should complete the 64bit cleanups in there. Signed-off-by:
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Alexander Viro authored
- get_user() __gu_val should be unsigned long (same as with i386 patch) - __copy_to_user() et.al. didn't have proper type checking - documented the casts in __copy_tofrom_user() calls with __force. Signed-off-by:
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Rusty Russell authored
nfsim gains sysctl support, and sure enough, --failtest uncovered an unregister when the registration had failed. Signed-off-by: -
Rusty Russell authored
Someone thought it would be clever if proc code ignores removal of non-existent entries. Hence, we missed that /proc/net/stat/ip_conntrack is never removed on module removal or init failure. Found by nfsim. Signed-off-by: -
Randy Dunlap authored
Somehow parport_pc.c ended up with mixed old-style and new-style module parameters, but mixing them is not allowed. Use module_param() instead of MODULE_PARM() -- cannot be mixed. Signed-off-by:
Randy Dunlap <rddunlap@osdl.org> Signed-off-by:
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William Lee Irwin III authored
Although the CG6 framebuffer is detected and initialized, without this patch all it displays is a blank screen. Tested on an Ultra 1 with a TGX+. Originally from Bob Breuer for the CG14. Signed-off-by:
Adam Kropelin <akropel1@rochester.rr.com> Acked-by:
William Irwin <wli@holomorphy.com> Signed-off-by:
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