- 16 Oct, 2007 40 commits
-
-
Nick Piggin authored
Convert udf to new aops. Also seem to have fixed pagecache corruption in udf_adinicb_commit_write -- page was marked uptodate when it is not. Also, fixed the silly setup where prepare_write was doing a kmap to be used in commit_write: just do kmap_atomic in write_end. Use libfs helpers to make this easier. Signed-off-by:
Nick Piggin <npiggin@suse.de> Cc: <bfennema@falcon.csc.calpoly.edu> Cc: Jan Kara <jack@ucw.cz> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
-
Nick Piggin authored
Signed-off-by:
-
Nick Piggin authored
Signed-off-by:
-
Nick Piggin authored
This also gets rid of a lot of useless read_file stuff. And also optimises the full page write case by marking a !uptodate page uptodate. Signed-off-by:
-
Nick Piggin authored
[mszeredi] - don't send zero length write requests - it is not legal for the filesystem to return with zero written bytes Signed-off-by:
Miklos Szeredi <mszeredi@suse.cz> Signed-off-by:
-
Nick Piggin authored
Signed-off-by:
-
Nick Piggin authored
[akpm@linux-foundation.org: fix against git-nfs] [peterz@infradead.org: fix against git-nfs] Signed-off-by:
Trond Myklebust <Trond.Myklebust@netapp.com> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by:
-
Nick Piggin authored
Signed-off-by:
-
Vladimir Saveliev authored
This patch makes reiserfs to use AOP_FLAG_CONT_EXPAND in order to get rid of the special generic_cont_expand routine Signed-off-by:
Vladimir Saveliev <vs@namesys.com> Signed-off-by:
-
Vladimir Saveliev authored
Convert reiserfs to new aops Signed-off-by:
-
Vladimir Saveliev authored
Make reiserfs to write via generic routines. Original reiserfs write optimized for big writes is deadlock rone Signed-off-by:
-
Nick Piggin authored
Signed-off-by:
Anders Larsen <al@alarsen.net> Signed-off-by:
-
Nick Piggin authored
Signed-off-by:
-
Nick Piggin authored
Signed-off-by:
-
Nick Piggin authored
Signed-off-by:
-
Nick Piggin authored
Signed-off-by:
-
Nick Piggin authored
Signed-off-by:
-
Nick Piggin authored
Rework the generic block "cont" routines to handle the new aops. Supporting cont_prepare_write would take quite a lot of code to support, so remove it instead (and we later convert all filesystems to use it). write_begin gets passed AOP_FLAG_CONT_EXPAND when called from generic_cont_expand, so filesystems can avoid the old hacks they used. Signed-off-by:
-
Steven Whitehouse authored
Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Steven Whitehouse <swhiteho@redhat.com> Signed-off-by:
-
Nick Piggin authored
Signed-off-by:
-
Nick Piggin authored
Convert ext4 to use write_begin()/write_end() methods. Signed-off-by:
Badari Pulavarty <pbadari@us.ibm.com> Signed-off-by:
-
Nick Piggin authored
Various fixes and improvements Signed-off-by:
-
Nick Piggin authored
Signed-off-by:
-
Nick Piggin authored
Signed-off-by:
-
Nick Piggin authored
Implement new aops for some of the simpler filesystems. Signed-off-by:
-
Nick Piggin authored
Restore the KERNEL_DS optimisation, especially helpful to the 2copy write path. This may be a pretty questionable gain in most cases, especially after the legacy 2copy write path is removed, but it doesn't cost much. Signed-off-by:
-
Dmitry Monakhov authored
Partial write can be easily supported by LO_CRYPT_NONE mode, but it is not easy in LO_CRYPT_CRYPTOAPI case, because of its block nature. I don't know who still used cryptoapi, but theoretically it is possible. So let's leave things as they are. Loop device doesn't support partial write before Nick's "write_begin/write_end" patch set, and let's it behave the same way after. Signed-off-by:
Dmitriy Monakhov <dmonakhov@openvz.org> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by:
-
Nick Piggin authored
These are intended to replace prepare_write and commit_write with more flexible alternatives that are also able to avoid the buffered write deadlock problems efficiently (which prepare_write is unable to do). [mark.fasheh@oracle.com: API design contributions, code review and fixes] [akpm@linux-foundation.org: various fixes] [dmonakhov@sw.ru: new aop block_write_begin fix] Signed-off-by:
Mark Fasheh <mark.fasheh@oracle.com> Signed-off-by:
-
Nick Piggin authored
New buffers against uptodate pages are simply be marked uptodate, while the buffer_new bit remains set. This causes error-case code to zero out parts of those buffers because it thinks they contain stale data: wrong, they are actually uptodate so this is a data loss situation. Fix this by actually clearning buffer_new and marking the buffer dirty. It makes sense to always clear buffer_new before setting a buffer uptodate. Signed-off-by:
-
Nick Piggin authored
Add an iterator data structure to operate over an iovec. Add usercopy operators needed by generic_file_buffered_write, and convert that function over. Signed-off-by:
-
Nick Piggin authored
Modify the core write() code so that it won't take a pagefault while holding a lock on the pagecache page. There are a number of different deadlocks possible if we try to do such a thing: 1. generic_buffered_write 2. lock_page 3. prepare_write 4. unlock_page+vmtruncate 5. copy_from_user 6. mmap_sem(r) 7. handle_mm_fault 8. lock_page (filemap_nopage) 9. commit_write 10. unlock_page a. sys_munmap / sys_mlock / others b. mmap_sem(w) c. make_pages_present d. get_user_pages e. handle_mm_fault f. lock_page (filemap_nopage) 2,8 - recursive deadlock if page is same 2,8;2,8 - ABBA deadlock is page is different 2,6;b,f - ABBA deadlock if page is same The solution is as follows: 1. If we find the destination page is uptodate, continue as normal, but use atomic usercopies which do not take pagefaults and do not zero the uncopied tail of the destination. The destination is already uptodate, so we can commit_write the full length even if there was a partial copy: it does not matter that the tail was not modified, because if it is dirtied and written back to disk it will not cause any problems (uptodate *means* that the destination page is as new or newer than the copy on disk). 1a. The above requires that fault_in_pages_readable correctly returns access information, because atomic usercopies cannot distinguish between non-present pages in a readable mapping, from lack of a readable mapping. 2. If we find the destination page is non uptodate, unlock it (this could be made slightly more optimal), then allocate a temporary page to copy the source data into. Relock the destination page and continue with the copy. However, instead of a usercopy (which might take a fault), copy the data from the pinned temporary page via the kernel address space. (also, rename maxlen to seglen, because it was confusing) This increases the CPU/memory copy cost by almost 50% on the affected workloads. That will be solved by introducing a new set of pagecache write aops in a subsequent patch. Signed-off-by: -
Nick Piggin authored
Hide some of the open-coded nr_segs tests into the iovec helpers. This is all to simplify generic_file_buffered_write, because that gets more complex in the next patch. Signed-off-by:
-
Nick Piggin authored
Quite a bit of code is used in maintaining these "cached pages" that are probably pretty unlikely to get used. It would require a narrow race where the page is inserted concurrently while this process is allocating a page in order to create the spare page. Then a multi-page write into an uncached part of the file, to make use of it. Next, the buffered write path (and others) uses its own LRU pagevec when it should be just using the per-CPU LRU pagevec (which will cut down on both data and code size cacheline footprint). Also, these private LRU pagevecs are emptied after just a very short time, in contrast with the per-CPU pagevecs that are persistent. Net result: 7.3 times fewer lru_lock acquisitions required to add the pages to pagecache for a bulk write (in 4K chunks). [this gets rid of some cond_resched() calls in readahead.c and mpage.c due to clashes in -mm. What put them there, and why? ] Signed-off-by:
-
Nick Piggin authored
If prepare_write fails with AOP_TRUNCATED_PAGE, or if commit_write fails, then we may have failed the write operation despite prepare_write having instantiated blocks past i_size. Fix this, and consolidate the trimming into one place. Signed-off-by:
-
Nick Piggin authored
Allow CONFIG_DEBUG_VM to switch off the prefaulting logic, to simulate the Makes the race much easier to hit. This is useful for demonstration and testing purposes, but is removed in a subsequent patch. Signed-off-by:
-
Andrew Morton authored
Rename some variables and fix some types. Signed-off-by:
Andrew Morton <akpm@osdl.org> Signed-off-by:
-
Andrew Morton authored
This reverts commit 6527c2bd, which fixed the following bug: When prefaulting in the pages in generic_file_buffered_write(), we only faulted in the pages for the firts segment of the iovec. If the second of successive segment described a mmapping of the page into which we're write()ing, and that page is not up-to-date, the fault handler tries to lock the already-locked page (to bring it up to date) and deadlocks. An exploit for this bug is in writev-deadlock-demo.c, in http://www.zip.com.au/~akpm/linux/patches/stuff/ext3-tools.tar.gz. (These demos assume blocksize < PAGE_CACHE_SIZE). The problem with this fix is that it takes the kernel back to doing a single prepare_write()/commit_write() per iovec segment. So in the worst case we'll run prepare_write+commit_write 1024 times where we previously would have run it once. The other problem with the fix is that it fix all the locking problems. <insert numbers obtained via ext3-tools's writev-speed.c here> And apparently this change killed NFS overwrite performance, because, I suppose, it talks to the server for each prepare_write+commit_write. So just back that patch out - we'll be fixing the deadlock by other means. Nick says: also it only ever actually papered over the bug, because after faulting in the pages, they might be unmapped or reclaimed. Signed-off-by:
-
Andrew Morton authored
This reverts commit 81b0c871, which was a bugfix against 6527c2bd ("[PATCH] generic_file_buffered_write(): deadlock on vectored write"), which we also revert. Signed-off-by:
-
Nick Piggin authored
Revert the patch from Neil Brown to optimise NFSD writev handling. Cc: Neil Brown <neilb@suse.de> Signed-off-by:
-
Hisashi Hifumi authored
While running some memory intensive load, system response deteriorated just after swap-out started. The cause of this problem is that when a PG_reclaim page is moved to the tail of the inactive LRU list in rotate_reclaimable_page(), lru_lock spin lock is acquired every page writeback . This deteriorates system performance and makes interrupt hold off time longer when swap-out started. Following patch solves this problem. I use pagevec in rotating reclaimable pages to mitigate LRU spin lock contention and reduce interrupt hold off time. I did a test that allocating and touching pages in multiple processes, and pinging to the test machine in flooding mode to measure response under memory intensive load. The test result is: -2.6.23-rc5 --- testmachine ping statistics --- 3000 packets transmitted, 3000 received, 0% packet loss, time 53222ms rtt min/avg/max/mdev = 0.074/0.652/172.228/7.176 ms, pipe 11, ipg/ewma 17.746/0.092 ms -2.6.23-rc5-patched --- testmachine ping statistics --- 3000 packets transmitted, 3000 received, 0% packet loss, time 51924ms rtt min/avg/max/mdev = 0.072/0.108/3.884/0.114 ms, pipe 2, ipg/ewma 17.314/0.091 ms Max round-trip-time was improved. The test machine spec is that 4CPU(3.16GHz, Hyper-threading enabled) 8GB memory , 8GB swap. I did ping test again to observe performance deterioration caused by taking a ref. -2.6.23-rc6-with-modifiedpatch --- testmachine ping statistics --- 3000 packets transmitted, 3000 received, 0% packet loss, time 53386ms rtt min/avg/max/mdev = 0.074/0.110/4.716/0.147 ms, pipe 2, ipg/ewma 17.801/0.129 ms The result for my original patch is as follows. -2.6.23-rc5-with-originalpatch --- testmachine ping statistics --- 3000 packets transmitted, 3000 received, 0% packet loss, time 51924ms rtt min/avg/max/mdev = 0.072/0.108/3.884/0.114 ms, pipe 2, ipg/ewma 17.314/0.091 ms The influence to response was small. [akpm@linux-foundation.org: fix uninitalised var warning] [hugh@veritas.com: fix locking] [randy.dunlap@oracle.com: fix function declaration] [hugh@veritas.com: fix BUG at include/linux/mm.h:220!] [hugh@veritas.com: kill redundancy in rotate_reclaimable_page] [hugh@veritas.com: move_tail_pages into lru_add_drain] Signed-off-by:
Hisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp> Signed-off-by:
-
