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2014-06-04mm: non-atomically mark page accessed during page cache allocation where ↵Mel Gorman
possible aops->write_begin may allocate a new page and make it visible only to have mark_page_accessed called almost immediately after. Once the page is visible the atomic operations are necessary which is noticable overhead when writing to an in-memory filesystem like tmpfs but should also be noticable with fast storage. The objective of the patch is to initialse the accessed information with non-atomic operations before the page is visible. The bulk of filesystems directly or indirectly use grab_cache_page_write_begin or find_or_create_page for the initial allocation of a page cache page. This patch adds an init_page_accessed() helper which behaves like the first call to mark_page_accessed() but may called before the page is visible and can be done non-atomically. The primary APIs of concern in this care are the following and are used by most filesystems. find_get_page find_lock_page find_or_create_page grab_cache_page_nowait grab_cache_page_write_begin All of them are very similar in detail to the patch creates a core helper pagecache_get_page() which takes a flags parameter that affects its behavior such as whether the page should be marked accessed or not. Then old API is preserved but is basically a thin wrapper around this core function. Each of the filesystems are then updated to avoid calling mark_page_accessed when it is known that the VM interfaces have already done the job. There is a slight snag in that the timing of the mark_page_accessed() has now changed so in rare cases it's possible a page gets to the end of the LRU as PageReferenced where as previously it might have been repromoted. This is expected to be rare but it's worth the filesystem people thinking about it in case they see a problem with the timing change. It is also the case that some filesystems may be marking pages accessed that previously did not but it makes sense that filesystems have consistent behaviour in this regard. The test case used to evaulate this is a simple dd of a large file done multiple times with the file deleted on each iterations. The size of the file is 1/10th physical memory to avoid dirty page balancing. In the async case it will be possible that the workload completes without even hitting the disk and will have variable results but highlight the impact of mark_page_accessed for async IO. The sync results are expected to be more stable. The exception is tmpfs where the normal case is for the "IO" to not hit the disk. The test machine was single socket and UMA to avoid any scheduling or NUMA artifacts. Throughput and wall times are presented for sync IO, only wall times are shown for async as the granularity reported by dd and the variability is unsuitable for comparison. As async results were variable do to writback timings, I'm only reporting the maximum figures. The sync results were stable enough to make the mean and stddev uninteresting. The performance results are reported based on a run with no profiling. Profile data is based on a separate run with oprofile running. async dd 3.15.0-rc3 3.15.0-rc3 vanilla accessed-v2 ext3 Max elapsed 13.9900 ( 0.00%) 11.5900 ( 17.16%) tmpfs Max elapsed 0.5100 ( 0.00%) 0.4900 ( 3.92%) btrfs Max elapsed 12.8100 ( 0.00%) 12.7800 ( 0.23%) ext4 Max elapsed 18.6000 ( 0.00%) 13.3400 ( 28.28%) xfs Max elapsed 12.5600 ( 0.00%) 2.0900 ( 83.36%) The XFS figure is a bit strange as it managed to avoid a worst case by sheer luck but the average figures looked reasonable. samples percentage ext3 86107 0.9783 vmlinux-3.15.0-rc4-vanilla mark_page_accessed ext3 23833 0.2710 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed ext3 5036 0.0573 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed ext4 64566 0.8961 vmlinux-3.15.0-rc4-vanilla mark_page_accessed ext4 5322 0.0713 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed ext4 2869 0.0384 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed xfs 62126 1.7675 vmlinux-3.15.0-rc4-vanilla mark_page_accessed xfs 1904 0.0554 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed xfs 103 0.0030 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed btrfs 10655 0.1338 vmlinux-3.15.0-rc4-vanilla mark_page_accessed btrfs 2020 0.0273 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed btrfs 587 0.0079 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed tmpfs 59562 3.2628 vmlinux-3.15.0-rc4-vanilla mark_page_accessed tmpfs 1210 0.0696 vmlinux-3.15.0-rc4-accessed-v3r25 init_page_accessed tmpfs 94 0.0054 vmlinux-3.15.0-rc4-accessed-v3r25 mark_page_accessed [akpm@linux-foundation.org: don't run init_page_accessed() against an uninitialised pointer] Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Tested-by: Prabhakar Lad <prabhakar.csengg@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-03-31GFS2: Fix address space from page functionSteven Whitehouse
Now that rgrps use the address space which is part of the super block, we need to update gfs2_mapping2sbd() to take account of that. The only way to do that easily is to use a different set of address_space_operations for rgrps. Reported-by: Abhi Das <adas@redhat.com> Tested-by: Abhi Das <adas@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2014-02-24GFS2: Move log buffer accounting to transactionSteven Whitehouse
Now we have a master transaction into which other transactions are merged, the accounting can be done using this master transaction. We no longer require the superblock fields which were being used for this function. In addition, this allows for a clean up in calc_reserved() making it rather easier understand. Also, by reducing the number of variables used to track the buffers being added and removed from the journal, a number of error checks are now no longer required. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2014-01-03GFS2: Use only a single address space for rgrpsSteven Whitehouse
Prior to this patch, GFS2 had one address space for each rgrp, stored in the glock. This patch changes them to use a single address space in the super block. This therefore saves (sizeof(struct address_space) * nr_of_rgrps) bytes of memory and for large filesystems, that can be significant. It would be nice to be able to do something similar and merge the inode metadata address space into the same global address space. However, that is rather more complicated as the on-disk location doesn't have a 1:1 mapping with the inodes in general. So while it could be done, it will be a more complicated operation as it requires changing a lot more code paths. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2013-12-13GFS2: Fix slab memory leak in gfs2_bufdataBob Peterson
This patch fixes a slab memory leak that sometimes can occur for files with a very short lifespan. The problem occurs when a dinode is deleted before it has gotten to the journal properly. In the leak scenario, the bd object is pinned for journal committment (queued to the metadata buffers queue: sd_log_le_buf) but is subsequently unpinned and dequeued before it finds its way to the ail or the revoke queue. In this rare circumstance, the bd object needs to be freed from slab memory, or it is forgotten. We have to be very careful how we do it, though, because multiple processes can call gfs2_remove_from_journal. In order to avoid double-frees, only the process that does the unpinning is allowed to free the bd. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2013-08-19GFS2: Move gfs2_sync_meta to lops.cSteven Whitehouse
Since gfs2_sync_meta() is only called from a single file, lets move it to lops.c where it is used, and mark it static. At the same time, we can clean up the meta_io.h header too. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2013-06-19GFS2: aggressively issue revokes in gfs2_log_flushBenjamin Marzinski
This patch looks at all the outstanding blocks in all the transactions on the log, and moves the completed ones to the ail2 list. Then it issues revokes for these blocks. This will hopefully speed things up in situations where there is a lot of contention for glocks, especially if they are acquired serially. revoke_lo_before_commit will issue at most one log block's full of these preemptive revokes. The amount of reserved log space that gfs2_log_reserve() ignores has been incremented to allow for this extra block. This patch also consolidates the common revoke instructions into one function, gfs2_add_revoke(). Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2013-04-08GFS2: replace gfs2_ail structure with gfs2_transBenjamin Marzinski
In order to allow transactions and log flushes to happen at the same time, gfs2 needs to move the transaction accounting and active items list code into the gfs2_trans structure. As a first step toward this, this patch removes the gfs2_ail structure, and handles the active items list in the gfs_trans structure. This keeps gfs2 from allocating an ail structure on log flushes, and gives us a struture that can later be used to store the transaction accounting outside of the gfs2 superblock structure. With this patch, at the end of a transaction, gfs2 will add the gfs2_trans structure to the superblock if there is not one already. This structure now has the active items fields that were previously in gfs2_ail. This is not necessary in the case where the transaction was simply used to add revokes, since these are never written outside of the journal, and thus, don't need an active items list. Also, in order to make sure that the transaction structure is not removed while it's still in use by gfs2_trans_end, unlocking the sd_log_flush_lock has to happen slightly later in ending the transaction. Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2013-01-29GFS2: Merge gfs2_attach_bufdata() into trans.cSteven Whitehouse
The locking in gfs2_attach_bufdata() was type specific (data/meta) which made the function rather confusing. This patch moves the core of gfs2_attach_bufdata() into trans.c renaming it gfs2_alloc_bufdata() and moving the locking into gfs2_trans_add_data()/gfs2_trans_add_meta() As a result all of the locking related to adding data and metadata to the journal is now in these two functions. This should help to clarify what is going on, and give us some opportunities to simplify in some cases. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-08-04gfs2: nuke pdflush from commentsArtem Bityutskiy
The pdflush thread is long gone, so this patch removes references to pdflush from gfs comments. Cc: Steven Whitehouse <swhiteho@redhat.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-28GFS2: Fixing double brelse'ing bh allocated in gfs2_meta_read when EIO occursMasatake YAMATO
This patch fixes buffer_head double free in following code path: gfs2_block_map => gfs2_meta_inode_buffer => gfs2_meta_indirect_buffer => gfs2_meta_read => release_metapath gfs2_block_map calls gfs2_meta_inode_buffer with &mp.mp_bh[0] as an argument. mp.mp_bh are filled with zero at the beginning of gfs2_block_map. If gfs2_meta_inode_buffer returns non-zero value, gfs2_block_map calls release_metapath to free buffers chained to mp.mp_bh. release_metapath checks each slot of mp.mp_bh[i] and free(with brelse) unless the slot is filled with NULL. &mp.mp_bh[0] passed to gfs2_meta_inode_buffer is filled at gfs2_meta_read. gfs2_meta_read is filled a buffer allocated with gfs2_getbuf even if EIO occurs. When EIO occurs, the allocated buffer is brelse'ed though the pointer(wrong poiner) points the brelse'ed is passed back to caller via an argument bhp. gfs2_meta_indirect_buffer, the caller also pass the wrong pointer to its caller with EIO. Finally gfs2_block_map gets both EIO and &mp.mp_bh[0] filled with the wrong pointer. release_metapath calls brelse again on the wrong pointer. Signed-off-by: Masatake YAMATO <yamato@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-05-11GFS2: Eliminate unused "new" parameter to gfs2_meta_indirect_bufferBob Peterson
It turns out that the "new" parameter to function gfs2_meta_indirect_buffer was always being passed in as zero. Therefore, this patch eliminates it and simplifies the function. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-05-02GFS2: eliminate log elements and simplifyBob Peterson
This patch eliminates the gfs2_log_element data structure and rolls its two components into the gfs2_bufdata. This makes the code easier to understand and makes it easier to migrate to a rbtree to keep the list sorted. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-04-24GFS2: Remove bd_list_trSteven Whitehouse
This is another clean up in the logging code. This per-transaction list was largely unused. Its main function was to ensure that the number of buffers in a transaction was correct, however that counter was only used to check the number of buffers in the bd_list_tr, plus an assert at the end of each transaction. With the assert now changed to use the calculated buffer counts, we can remove both bd_list_tr and its associated counter. This should make the code easier to understand as well as shrinking a couple of structures. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2011-11-08GFS2: Fix up REQ flagsSteven Whitehouse
Christoph has split up REQ_PRIO from REQ_META. That means that we can drop REQ_PRIO from places where is it not needed. I'm not at all sure that the combination WRITE_FLUSH_FUA | REQ_PRIO makes any kind of sense, anyway. In addition, I've added REQ_META to one place in the code where it was missing. REQ_PRIO has been left for read/writes triggered by glock acquisition and writeback only. We can adjust it again if required, but these are the most important points from a performance perspective. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> Cc: Christoph Hellwig <hch@infradead.org>
2011-08-23block: separate priority boosting from REQ_METAChristoph Hellwig
Add a new REQ_PRIO to let requests preempt others in the cfq I/O schedule, and lave REQ_META purely for marking requests as metadata in blktrace. All existing callers of REQ_META except for XFS are updated to also set REQ_PRIO for now. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Namhyung Kim <namhyung@gmail.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-04-20GFS2: Improve tracing support (adds two flags)Steven Whitehouse
This adds support for two new flags. One keeps track of whether the glock is on the LRU list or not. The other isn't really a flag as such, but an indication of whether the glock has an attached object or not. This indication is reported without any locking, which is ok since we do not dereference the object pointer but merely report whether it is NULL or not. Also, this fixes one place where a tracepoint was missing, which was at the point we remove deallocated blocks from the journal. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2011-03-24Merge branch 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds
* 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-block: (65 commits) Documentation/iostats.txt: bit-size reference etc. cfq-iosched: removing unnecessary think time checking cfq-iosched: Don't clear queue stats when preempt. blk-throttle: Reset group slice when limits are changed blk-cgroup: Only give unaccounted_time under debug cfq-iosched: Don't set active queue in preempt block: fix non-atomic access to genhd inflight structures block: attempt to merge with existing requests on plug flush block: NULL dereference on error path in __blkdev_get() cfq-iosched: Don't update group weights when on service tree fs: assign sb->s_bdi to default_backing_dev_info if the bdi is going away block: Require subsystems to explicitly allocate bio_set integrity mempool jbd2: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging jbd: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging fs: make fsync_buffers_list() plug mm: make generic_writepages() use plugging blk-cgroup: Add unaccounted time to timeslice_used. block: fixup plugging stubs for !CONFIG_BLOCK block: remove obsolete comments for blkdev_issue_zeroout. blktrace: Use rq->cmd_flags directly in blk_add_trace_rq. ... Fix up conflicts in fs/{aio.c,super.c}
2011-03-14GFS2: Update to AIL list lockingSteven Whitehouse
The previous patch missed a couple of places where the AIL list needed locking, so this fixes up those places, plus a comment is corrected too. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Chinner <dchinner@redhat.com>
2011-03-10block: kill off REQ_UNPLUGJens Axboe
With the plugging now being explicitly controlled by the submitter, callers need not pass down unplugging hints to the block layer. If they want to unplug, it's because they manually plugged on their own - in which case, they should just unplug at will. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-10block: remove per-queue pluggingJens Axboe
Code has been converted over to the new explicit on-stack plugging, and delay users have been converted to use the new API for that. So lets kill off the old plugging along with aops->sync_page(). Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-10-26writeback: remove nonblocking/encountered_congestion referencesWu Fengguang
This removes more dead code that was somehow missed by commit 0d99519efef (writeback: remove unused nonblocking and congestion checks). There are no behavior change except for the removal of two entries from one of the ext4 tracing interface. The nonblocking checks in ->writepages are no longer used because the flusher now prefer to block on get_request_wait() than to skip inodes on IO congestion. The latter will lead to more seeky IO. The nonblocking checks in ->writepage are no longer used because it's redundant with the WB_SYNC_NONE check. We no long set ->nonblocking in VM page out and page migration, because a) it's effectively redundant with WB_SYNC_NONE in current code b) it's old semantic of "Don't get stuck on request queues" is mis-behavior: that would skip some dirty inodes on congestion and page out others, which is unfair in terms of LRU age. Inspired by Christoph Hellwig. Thanks! Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: David Howells <dhowells@redhat.com> Cc: Sage Weil <sage@newdream.net> Cc: Steve French <sfrench@samba.org> Cc: Chris Mason <chris.mason@oracle.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-07block: unify flags for struct bio and struct requestChristoph Hellwig
Remove the current bio flags and reuse the request flags for the bio, too. This allows to more easily trace the type of I/O from the filesystem down to the block driver. There were two flags in the bio that were missing in the requests: BIO_RW_UNPLUG and BIO_RW_AHEAD. Also I've renamed two request flags that had a superflous RW in them. Note that the flags are in bio.h despite having the REQ_ name - as blkdev.h includes bio.h that is the only way to go for now. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-05-12GFS2: Eliminate useless err variableBob Peterson
This patch removes an unneeded "err" variable that is always returned as zero. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2010-05-05GFS2: Various gfs2_logd improvementsBenjamin Marzinski
This patch contains various tweaks to how log flushes and active item writeback work. gfs2_logd is now managed by a waitqueue, and gfs2_log_reseve now waits for gfs2_logd to do the log flushing. Multiple functions were rewritten to remove the need to call gfs2_log_lock(). Instead of using one test to see if gfs2_logd had work to do, there are now seperate tests to check if there are two many buffers in the incore log or if there are two many items on the active items list. This patch is a port of a patch Steve Whitehouse wrote about a year ago, with some minor changes. Since gfs2_ail1_start always submits all the active items, it no longer needs to keep track of the first ai submitted, so this has been removed. In gfs2_log_reserve(), the order of the calls to prepare_to_wait_exclusive() and wake_up() when firing off the logd thread has been switched. If it called wake_up first there was a small window for a race, where logd could run and return before gfs2_log_reserve was ready to get woken up. If gfs2_logd ran, but did not free up enough blocks, gfs2_log_reserve() would be left waiting for gfs2_logd to eventualy run because it timed out. Finally, gt_logd_secs, which controls how long to wait before gfs2_logd times out, and flushes the log, can now be set on mount with ar_commit. Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2010-03-01GFS2: Metadata address space clean upSteven Whitehouse
Since the start of GFS2, an "extra" inode has been used to store the metadata belonging to each inode. The only reason for using this inode was to have an extra address space, the other fields were unused. This means that the memory usage was rather inefficient. The reason for keeping each inode's metadata in a separate address space is that when glocks are requested on remote nodes, we need to be able to efficiently locate the data and metadata which relating to that glock (inode) in order to sync or sync and invalidate it (depending on the remotely requested lock mode). This patch adds a new type of glock, which has in addition to its normal fields, has an address space. This applies to all inode and rgrp glocks (but to no other glock types which remain as before). As a result, we no longer need to have the second inode. This results in three major improvements: 1. A saving of approx 25% of memory used in caching inodes 2. A removal of the circular dependency between inodes and glocks 3. No confusion between "normal" and "metadata" inodes in super.c Although the first of these is the more immediately apparent, the second is just as important as it now enables a number of clean ups at umount time. Those will be the subject of future patches. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2010-01-11GFS2: Use MAX_LFS_FILESIZE for meta inode sizeSteven Whitehouse
Using ~0ULL was cauing sign issues in filemap_fdatawrite_range, so use MAX_LFS_FILESIZE instead. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-05-22GFS2: Clean up some file namesSteven Whitehouse
This patch renames the ops_*.c files which have no counterpart without the ops_ prefix in order to shorten the name and make it more readable. In addition, ops_address.h (which was very small) is moved into inode.h and inode.h is cleaned up by adding extern where required. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-05-11GFS2: Optimise writepage for metadataSteven Whitehouse
This adds a GFS2 specific writepage for metadata, rather than continuing to use the VFS function. As a result we now tag all our metadata I/O with the correct flag so that blktraces will now be less confusing. Also, the generic function was checking for a number of corner cases which cannot happen on the metadata address spaces so that this should be faster too. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-05-11GFS2: Update the rw flagsSteven Whitehouse
After Jens recent updates: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=a1f242524c3c1f5d40f1c9c343427e34d1aadd6e et al. this is a patch to bring gfs2 uptodate with the core code. Also I've managed to squash another call to ll_rw_block() along the way. There is still one part of the GFS2 I/O paths which are not correctly annotated and that is due to the sharing of the writeback code between the data and metadata address spaces. I would like to change that too, but this patch is still worth doing on its own, I think. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-03-24GFS2: Clean up of glops.cSteven Whitehouse
This cleans up a number of bits of code mostly based in glops.c. A couple of simple functions have been merged into the callers to make it more obvious what is going on, the mysterious raising of i_writecount around the truncate_inode_pages() call has been removed. The meta_go_* operations have been renamed rgrp_go_* since that is the only lock type that they are used with. The unused argument of gfs2_read_sb has been removed. Also a bug has been fixed where a check for the rindex inode was in the wrong callback. More comments are added, and the debugging code is improved too. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-03-24GFS2: Merge lock_dlm module into GFS2Steven Whitehouse
This is the big patch that I've been working on for some time now. There are many reasons for wanting to make this change such as: o Reducing overhead by eliminating duplicated fields between structures o Simplifcation of the code (reduces the code size by a fair bit) o The locking interface is now the DLM interface itself as proposed some time ago. o Fewer lookups of glocks when processing replies from the DLM o Fewer memory allocations/deallocations for each glock o Scope to do further optimisations in the future (but this patch is more than big enough for now!) Please note that (a) this patch relates to the lock_dlm module and not the DLM itself, that is still a separate module; and (b) that we retain the ability to build GFS2 as a standalone single node filesystem with out requiring the DLM. This patch needs a lot of testing, hence my keeping it I restarted my -git tree after the last merge window. That way, this has the maximum exposure before its merged. This is (modulo a few minor bug fixes) the same patch that I've been posting on and off the the last three months and its passed a number of different tests so far. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-06-27[GFS2] Clean up the glock coreSteven Whitehouse
This patch implements a number of cleanups to the core of the GFS2 glock code. As a result a lot of code is removed. It looks like a really big change, but actually a large part of this patch is either removing or moving existing code. There are some new bits too though, such as the new run_queue() function which is considerably streamlined. Highlights of this patch include: o Fixes a cluster coherency bug during SH -> EX lock conversions o Removes the "glmutex" code in favour of a single bit lock o Removes the ->go_xmote_bh() for inodes since it was duplicating ->go_lock() o We now only use the ->lm_lock() function for both locks and unlocks (i.e. unlock is a lock with target mode LM_ST_UNLOCKED) o The fast path is considerably shortly, giving performance gains especially with lock_nolock o The glock_workqueue is now used for all the callbacks from the DLM which allows us to simplify the lock_dlm module (see following patch) o The way is now open to make further changes such as eliminating the two threads (gfs2_glockd and gfs2_scand) in favour of a more efficient scheme. This patch has undergone extensive testing with various test suites so it should be pretty stable by now. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> Cc: Bob Peterson <rpeterso@redhat.com>
2008-05-12[GFS2] filesystem consistency error from do_stripBob Peterson
This patch fixes a GFS2 filesystem consistency error reported from function do_strip. The problem was caused by a timing window that allowed two vfs inodes to be created in memory that point to the same file. The problem is fixed by making the vfs's iget_test, iget_set mechanism check and set a new bit in the in-core gfs2_inode structure while the vfs inode spin_lock is held. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-01-25[GFS2] Fix typoBob Peterson
This patch fixes a minor typo. Surprisingly, it still compiled. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-01-25[GFS2] Function meta_read optimizationBob Peterson
This patch optimizes function gfs2_meta_read. Basically, gfs2_meta_wait was being called regardless of whether a disk read was requested. This just pulls that wait into the if that triggers the read. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-01-25[GFS2] Add sync_page to metadata address space operationsSteven Whitehouse
This set of address space operations was missing a sync_page operation. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-01-25[GFS2] Remove useless i_cache from inodesSteven Whitehouse
The i_cache was designed to keep references to the indirect blocks used during block mapping so that they didn't have to be looked up continually. The idea failed because there are too many places where the i_cache needs to be freed, and this has in the past been the cause of many bugs. In addition there was no performance benefit being gained since the disk blocks in question were cached anyway. So this patch removes it in order to simplify the code to prepare for other changes which would otherwise have had to add further support for this feature. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10[GFS2] Data corruption fixWendy Cheng
* GFS2 has been using i_cache array to store its indirect meta blocks. Its flush routine doesn't correctly clean up all the entries. The problem would show while multiple nodes do simultaneous writes to the same file. Upon glock exclusive lock transfer, if the file is a sparse file with large file size where the indirect meta blocks span multiple array entries with "zero" entries in between. The flush routine prematurely stops the flushing that leaves old (stale) entries around. This leads to several nasty issues, including data corruption. * Fix gfs2_get_block_noalloc checking to correctly return EIO upon unmapped buffer. Signed-off-by: Wendy Cheng <wcheng@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10[GFS2] Clean up journaled data writingSteven Whitehouse
This patch cleans up the code for writing journaled data into the log. It also removes the need to allocate a small "tag" structure for each block written into the log. Instead we just keep count of the outstanding I/O so that we can be sure that its all been written at the correct time. Another result of this patch is that a number of ll_rw_block() calls have become submit_bh() calls, closing some races at the same time. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10[GFS2] Clean up gfs2_trans_add_revoke()Steven Whitehouse
The following alters gfs2_trans_add_revoke() to take a struct gfs2_bufdata as an argument. This eliminates the memory allocation which was previously required by making use of the already existing struct gfs2_bufdata. It makes some sanity checks to ensure that the gfs2_bufdata has been removed from all the lists before its recycled as a revoke structure. This saves one memory allocation and one free per revoke structure. Also as a result, and to simplify the locking, since there is no longer any blocking code in gfs2_trans_add_revoke() we must hold the log lock whenever this function is called. This reduces the amount of times we take and unlock the log lock. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10[GFS2] Move pin/unpin into lops.c, clean up lockingSteven Whitehouse
gfs2_pin and gfs2_unpin are only used in lops.c, despite being defined in meta_io.c, so this patch moves them into lops.c and makes them static. At the same time, its possible to clean up the locking in the buf and databuf _lo_add() functions so that we only need to grab the spinlock once. Also we have to move lock_buffer() around the _lo_add() functions since we can't do that in gfs2_pin() any more since we hold the spinlock for the duration of that function. As a result, the code shrinks by 12 lines and we do far fewer operations when adding buffers to the log. It also makes the code somewhat easier to read & understand. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-07-09[GFS2] assertion failure after writing to journaled file, umountRobert Peterson
This patch passes all my nasty tests that were causing the code to fail under one circumstance or another. Here is a complete summary of all changes from today's git tree, in order of appearance: 1. There are now separate variables for metadata buffer accounting. 2. Variable sd_log_num_hdrs is no longer needed, since the header accounting is taken care of by the reserve/refund sequence. 3. Fixed a tiny grammatical problem in a comment. 4. Added a new function "calc_reserved" to calculate the reserved log space. This isn't entirely necessary, but it has two benefits: First, it simplifies the gfs2_log_refund function greatly. Second, it allows for easier debugging because I could sprinkle the code with calls to this function to make sure the accounting is proper (by adding asserts and printks) at strategic point of the code. 5. In log_pull_tail there apparently was a kludge to fix up the accounting based on a "pull" parameter. The buffer accounting is now done properly, so the kludge was removed. 6. File sync operations were making a call to gfs2_log_flush that writes another journal header. Since that header was unplanned for (reserved) by the reserve/refund sequence, the free space had to be decremented so that when log_pull_tail gets called, the free space is be adjusted properly. (Did I hear you call that a kludge? well, maybe, but a lot more justifiable than the one I removed). 7. In the gfs2_log_shutdown code, it optionally syncs the log by specifying the PULL parameter to log_write_header. I'm not sure this is necessary anymore. It just seems to me there could be cases where shutdown is called while there are outstanding log buffers. 8. In the (data)buf_lo_before_commit functions, I changed some offset values from being calculated on the fly to being constants. That simplified some code and we might as well let the compiler do the calculation once rather than redoing those cycles at run time. 9. This version has my rewritten databuf_lo_add function. This version is much more like its predecessor, buf_lo_add, which makes it easier to understand. Again, this might not be necessary, but it seems as if this one works as well as the previous one, maybe even better, so I decided to leave it in. 10. In databuf_lo_before_commit, a previous data corruption problem was caused by going off the end of the buffer. The proper solution is to have the proper limit in place, rather than stopping earlier. (Thus my previous attempt to fix it is wrong). If you don't wrap the buffer, you're stopping too early and that causes more log buffer accounting problems. 11. In lops.h there are two new (previously mentioned) constants for figuring out the data offset for the journal buffers. 12. There are also two new functions, buf_limit and databuf_limit to calculate how many entries will fit in the buffer. 13. In function gfs2_meta_wipe, it needs to distinguish between pinned metadata buffers and journaled data buffers for proper journal buffer accounting. It can't use the JDATA gfs2_inode flag because it's sometimes passed the "real" inode and sometimes the "metadata inode" and the inode flags will be random bits in a metadata gfs2_inode. It needs to base its decision on which was passed in. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-02-11[PATCH] Transform kmem_cache_alloc()+memset(0) -> kmem_cache_zalloc().Robert P. J. Day
Replace appropriate pairs of "kmem_cache_alloc()" + "memset(0)" with the corresponding "kmem_cache_zalloc()" call. Signed-off-by: Robert P. J. Day <rpjday@mindspring.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: Roland McGrath <roland@redhat.com> Cc: James Bottomley <James.Bottomley@steeleye.com> Cc: Greg KH <greg@kroah.com> Acked-by: Joel Becker <Joel.Becker@oracle.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Jan Kara <jack@ucw.cz> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: James Morris <jmorris@namei.org> Cc: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-11-30[GFS2] Reduce number of arguments to meta_io.c:getbuf()Steven Whitehouse
Since the superblock and the address_space are determined by the glock, we might as well just pass that as the argument since all the callers already have that available. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-11-30[GFS2] Move gfs2_meta_syncfs() into log.cSteven Whitehouse
By moving gfs2_meta_syncfs() into log.c, gfs2_ail1_start() can be made static. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-11-30[GFS2] Fix journal flush problemSteven Whitehouse
This fixes a bug which resulted in poor performance due to flushing the journal too often. The code path in question was via the inode_go_sync() function in glops.c. The solution is not to flush the journal immediately when inodes are ejected from memory, but batch up the work for glockd to deal with later on. This means that glocks may now live on beyond the end of the lifetime of their inodes (but not very much longer in the normal case). Also fixed in this patch is a bug (which was hidden by the bug mentioned above) in calculation of the number of free journal blocks. The gfs2_logd process has been altered to be more responsive to the journal filling up. We now wake it up when the number of uncommitted journal blocks has reached the threshold level rather than trying to flush directly at the end of each transaction. This again means doing fewer, but larger, log flushes in general. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-10-03[GFS2] Move logging code into log.c (mostly)Steven Whitehouse
This moves the logging code from meta_io.c into log.c and glops.c. As a result the routines can now be static and all the logging code is together in log.c, leaving meta_io.c with just metadata i/o code in it. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-10-02[GFS2] Mark metadata reads for blktraceSteven Whitehouse
Mark the metadata reads so that blktrace knows what they are. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-09-28[GFS2] inode_diet: Replace inode.u.generic_ip with inode.i_private (gfs)Theodore Ts'o
The following patches reduce the size of the VFS inode structure by 28 bytes on a UP x86. (It would be more on an x86_64 system). This is a 10% reduction in the inode size on a UP kernel that is configured in a production mode (i.e., with no spinlock or other debugging functions enabled; if you want to save memory taken up by in-core inodes, the first thing you should do is disable the debugging options; they are responsible for a huge amount of bloat in the VFS inode structure). This patch: The filesystem or device-specific pointer in the inode is inside a union, which is pretty pointless given that all 30+ users of this field have been using the void pointer. Get rid of the union and rename it to i_private, with a comment to explain who is allowed to use the void pointer. This is just a cleanup, but it allows us to reuse the union 'u' for something something where the union will actually be used. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Steven Whitehouse <swhiteho@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org>