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2012-01-28Merge branch 'for-linus' of ↵Linus Torvalds9-36/+60
git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: Btrfs: fix reservations in btrfs_page_mkwrite Btrfs: advance window_start if we're using a bitmap btrfs: mask out gfp flags in releasepage Btrfs: fix enospc error caused by wrong checks of the chunk Btrfs: do not defrag a file partially Btrfs: fix warning for 32-bit build of fs/btrfs/check-integrity.c Btrfs: use cluster->window_start when allocating from a cluster bitmap Btrfs: Check for NULL page in extent_range_uptodate btrfs: Fix busyloops in transaction waiting code Btrfs: make sure a bitmap has enough bytes Btrfs: fix uninit warning in backref.c
2012-01-27Btrfs: fix reservations in btrfs_page_mkwriteChris Mason1-2/+8
Josef fixed btrfs_page_mkwrite to properly release reserved extents if there was an error. But if we fail to get a reservation and we fail to dirty the inode (for ENOSPC reasons), we'll end up trying to release a reservation we never had. This makes sure we only release if we were able to reserve. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-01-26Btrfs: advance window_start if we're using a bitmapJosef Bacik1-0/+1
If we span a long area in a bitmap we could end up taking a lot of time searching to the next free area if we're searching from the original window_start, so advance window_start in order to make sure we don't do any superficial searching. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-01-26btrfs: mask out gfp flags in releasepageDavid Sterba1-0/+7
btree_releasepage is a callback and can be passed unknown gfp flags and then they may end up in kmem_cache_alloc called from alloc_extent_state, slab allocator will BUG_ON when there is HIGHMEM or DMA32 flag set. This may happen when btrfs is mounted from a loop device, which masks out __GFP_IO flag. The check in try_release_extent_state 3399 if ((mask & GFP_NOFS) == GFP_NOFS) 3400 mask = GFP_NOFS; will not work and passes unfiltered flags further resulting in crash at mm/slab.c:2963 [<000000000024ae4c>] cache_alloc_refill+0x3b4/0x5c8 [<000000000024c810>] kmem_cache_alloc+0x204/0x294 [<00000000001fd3c2>] mempool_alloc+0x52/0x170 [<000003c000ced0b0>] alloc_extent_state+0x40/0xd4 [btrfs] [<000003c000cee5ae>] __clear_extent_bit+0x38a/0x4cc [btrfs] [<000003c000cee78c>] try_release_extent_state+0x9c/0xd4 [btrfs] [<000003c000cc4c66>] btree_releasepage+0x7e/0xd0 [btrfs] [<0000000000210d84>] shrink_page_list+0x6a0/0x724 [<0000000000211394>] shrink_inactive_list+0x230/0x578 [<0000000000211bb8>] shrink_list+0x6c/0x120 [<0000000000211e4e>] shrink_zone+0x1e2/0x228 [<0000000000211f24>] shrink_zones+0x90/0x254 [<0000000000213410>] do_try_to_free_pages+0xac/0x420 [<0000000000213ae0>] try_to_free_pages+0x13c/0x1b0 [<0000000000204e6c>] __alloc_pages_nodemask+0x5b4/0x9a8 [<00000000001fb04a>] grab_cache_page_write_begin+0x7e/0xe8 Signed-off-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-01-26Btrfs: fix enospc error caused by wrong checks of the chunkMiao Xie1-22/+27
When we did sysbench test for inline files, enospc error happened easily though there was lots of free disk space which could be allocated for new chunks. Reproduce steps: # mkfs.btrfs -b $((2 * 1024 * 1024 * 1024)) <test partition> # mount <test partition> /mnt # ulimit -n 102400 # cd /mnt # sysbench --num-threads=1 --test=fileio --file-num=81920 \ > --file-total-size=80M --file-block-size=1K --file-io-mode=sync \ > --file-test-mode=seqwr prepare # sysbench --num-threads=1 --test=fileio --file-num=81920 \ > --file-total-size=80M --file-block-size=1K --file-io-mode=sync \ > --file-test-mode=seqwr run <soon later, BUG_ON() was triggered by enospc error> The reason of this bug is: Now, we can reserve space which is larger than the free space in the chunks if we have enough free disk space which can be used for new chunks. By this way, the space allocator should allocate a new chunk by force if there is no free space in the free space cache. But there are two wrong checks which break this operation. One is if (ret == -ENOSPC && num_bytes > min_alloc_size) in btrfs_reserve_extent(), it is wrong, we should try to allocate a new chunk even we fail to allocate free space by minimum allocable size. The other is if (space_info->force_alloc) force = space_info->force_alloc; in do_chunk_alloc(). It makes the allocator ignore CHUNK_ALLOC_FORCE If someone sets ->force_alloc to CHUNK_ALLOC_LIMITED, and makes the enospc error happen. Fix these two wrong checks. Especially the second one, we fix it by changing the value of CHUNK_ALLOC_LIMITED and CHUNK_ALLOC_FORCE, and make CHUNK_ALLOC_FORCE greater than CHUNK_ALLOC_LIMITED since CHUNK_ALLOC_FORCE has higher priority. And if the value which is passed in by the caller is greater than ->force_alloc, use the passed value. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-01-26Btrfs: do not defrag a file partiallyLiu Bo1-1/+1
xfstests 218 complains that btrfs defrags a file partially: After: 1 Write backwards sync, but contiguous - should defrag to 1 extent Before: 10 -After: 1 +After: 2 To fix this, we need to set max_to_defrag count properly. Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-01-26Btrfs: fix warning for 32-bit build of fs/btrfs/check-integrity.cStefan Behrens1-5/+6
There have been 4 warnings on 32-bit build, they are herewith fixed. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-01-26Btrfs: use cluster->window_start when allocating from a cluster bitmapJosef Bacik1-1/+1
We specifically set window_start in the cluster struct to indicate where the cluster starts in a bitmap, but we've been using min_start to indicate where we're searching from. This is usually the start of the blockgroup, so essentially means we're constantly searching from the start of any bitmap we find, which completely negates all the trouble we go to in order to setup a cluster. So start using window_start to make sure we actually use the area we found. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-01-26Btrfs: Check for NULL page in extent_range_uptodateMitch Harder1-0/+2
A user has encountered a NULL pointer kernel oops in btrfs when encountering media errors. The problem has been identified as an unhandled NULL pointer returned from find_get_page(). This modification simply checks for a NULL page, and returns with an error if found (the extent_range_uptodate() function returns 1 on errors). After testing this patch, the user reported that the error with the NULL pointer oops was solved. However, there is still a remaining problem with a thread becoming stuck in wait_on_page_locked(page) in the read_extent_buffer_pages(...) function in extent_io.c for (i = start_i; i < num_pages; i++) { page = extent_buffer_page(eb, i); wait_on_page_locked(page); if (!PageUptodate(page)) ret = -EIO; } This patch leaves the issue with the locked page yet to be resolved. Signed-off-by: Mitch Harder <mitch.harder@sabayonlinux.org> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-01-26btrfs: Fix busyloops in transaction waiting codeJan Kara1-2/+4
wait_log_commit() and wait_for_writer() were using slightly different conditions for deciding whether they should call schedule() and whether they should continue in the wait loop. Thus it could happen that we busylooped when the first condition was not true while the second one was. That is burning CPU cycles needlessly and is deadly on UP machines... Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-01-26Btrfs: make sure a bitmap has enough bytesJosef Bacik1-1/+1
We have only been checking for min_bytes available in bitmap entries, but we won't successfully setup a bitmap cluster unless it has at least bytes in the bitmap, so in the common case min_bytes is 4k and we want something like 2MB, so if there are a bunch of bitmap entries with less than 2mb's in them, we'll search all them anyway, which is suboptimal. Fix this check. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-01-26Btrfs: fix uninit warning in backref.cJan Schmidt1-2/+2
Added initialization with the declaration of ret. It isn't set later on the switch-default branch (which should never be taken). Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-01-17Merge branch 'btrfs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfsLinus Torvalds7-125/+110
* 'btrfs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: btrfs: take allocation of ->tree_root into open_ctree() btrfs: let ->s_fs_info point to fs_info, not root... btrfs: consolidate failure exits in btrfs_mount() a bit btrfs: make free_fs_info() call ->kill_sb() unconditional btrfs: merge free_fs_info() calls on fill_super failures btrfs: kill pointless reassignment of ->s_fs_info in btrfs_fill_super() btrfs: make open_ctree() return int btrfs: sanitizing ->fs_info, part 5 btrfs: sanitizing ->fs_info, part 4 btrfs: sanitizing ->fs_info, part 3 btrfs: sanitizing ->fs_info, part 2 btrfs: sanitizing ->fs_info, part 1 btrfs: fix a deadlock in btrfs_scan_one_device() btrfs: fix mount/umount race btrfs: get ->kill_sb() of its own btrfs: preparation to fixing mount/umount race
2012-01-17Merge branch 'for-linus' of ↵Linus Torvalds33-921/+6746
git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (62 commits) Btrfs: use larger system chunks Btrfs: add a delalloc mutex to inodes for delalloc reservations Btrfs: space leak tracepoints Btrfs: protect orphan block rsv with spin_lock Btrfs: add allocator tracepoints Btrfs: don't call btrfs_throttle in file write Btrfs: release space on error in page_mkwrite Btrfs: fix btrfsck error 400 when truncating a compressed Btrfs: do not use btrfs_end_transaction_throttle everywhere Btrfs: add balance progress reporting Btrfs: allow for resuming restriper after it was paused Btrfs: allow for canceling restriper Btrfs: allow for pausing restriper Btrfs: add skip_balance mount option Btrfs: recover balance on mount Btrfs: save balance parameters to disk Btrfs: soft profile changing mode (aka soft convert) Btrfs: implement online profile changing Btrfs: do not reduce profile in do_chunk_alloc() Btrfs: virtual address space subset filter ... Fix up trivial conflict in fs/btrfs/ioctl.c due to the use of the new mnt_drop_write_file() helper.
2012-01-16Btrfs: use larger system chunksChris Mason2-1/+4
system chunks by default are very small. This makes them slightly larger and also fixes the conditional checks to make sure we don't allocate a billion of them at once. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-01-16Btrfs: add a delalloc mutex to inodes for delalloc reservationsJosef Bacik5-16/+7
I was using i_mutex for this, but we're getting bogus lockdep warnings by doing that and theres no real way to get rid of those, so just stop using i_mutex to protect delalloc metadata reservations and use a delalloc mutex instead. This shouldn't be contended often at all, only if you are writing and mmap writing to the file at the same time. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2012-01-16Btrfs: space leak tracepointsJosef Bacik4-20/+89
This in addition to a script in my btrfs-tracing tree will help track down space leaks when we're getting space left over in block groups on umount. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2012-01-16Btrfs: protect orphan block rsv with spin_lockJosef Bacik1-4/+19
We've been seeing warnings coming out of the orphan commit stuff forever from ceph. Turns out it's because we're racing with checking if the orphan block reserve is set, because we clear it outside of the spin_lock. So leave the normal fastpath checks where they are, but take the spin_lock and _recheck_ to make sure we haven't had an orphan block rsv added in the meantime. Then clear the root's orphan block rsv and release the lock. With this patch a user said the warnings went away and they usually showed up pretty soon after he started ceph. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2012-01-16Btrfs: add allocator tracepointsJosef Bacik2-1/+20
I used these tracepoints when figuring out what the cluster stuff was doing, so add them to mainline in case we need to profile this stuff again. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com>
2012-01-16Btrfs: don't call btrfs_throttle in file writeJosef Bacik1-1/+0
Btrfs_throttle will make us wait if there is a currently committing transaction until we can open new transactions, which is ridiculous since we don't actually start any transactions within the file write path anyway, so all this does is introduce big latencies if we have a sync/fsync heavy workload going on while somebody else is trying to do work. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-01-16Btrfs: release space on error in page_mkwriteJosef Bacik1-1/+1
If updating the inode gave us an ENOSPC we were just returning in page_mkwrite, which is a problem since we make our reservation right before trying to update the inode, so fix the out label so that we actually free our reservation. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-01-16Btrfs: fix btrfsck error 400 when truncating a compressedMiao Xie1-7/+1
Reproduce steps: # mkfs.btrfs /dev/sdb5 # mount /dev/sdb5 -o compress=lzo /mnt # dd if=/dev/zero of=/mnt/tmpfile bs=128K count=1 # sync # truncate -s 64K /mnt/tmpfile root 5 inode 257 errors 400 This is because of the wrong if condition, which is used to check if we should subtract the bytes of the dropped range from i_blocks/i_bytes of i-node or not. When we truncate a compressed extent, btrfs substracts the bytes of the whole extent, it's wrong. We should substract the real size that we truncate, no matter it is a compressed extent or not. Fix it. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-01-16Btrfs: do not use btrfs_end_transaction_throttle everywhereJosef Bacik2-10/+10
A user reported a problem where things like open with O_CREAT would take up to 30 seconds when he had nfs activity on the same mount. This is because all of our quick metadata operations, like create, symlink etc all do btrfs_end_transaction_throttle, which if the transaction is blocked will wait for the commit to complete before it returns. This adds a ridiculous amount of latency and isn't really needed. The normal btrfs_end_transaction will mark the transaction as blocked and wake the transaction kthread up if it thinks the transaction needs to end (this being in the running out of global reserve space scenario), and this is all that is really needed since we've already done everything we're going to do, we just need to return. This should help people with the latency they were seeing when using synchronous heavy workloads. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-01-16Merge branch 'integrity-check-patch-v2' of ↵Chris Mason10-10/+3201
git://btrfs.giantdisaster.de/git/btrfs into integration Conflicts: fs/btrfs/ctree.h fs/btrfs/super.c Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-01-16Merge branch 'for-chris' of git://git.jan-o-sch.net/btrfs-unstable into ↵Chris Mason21-419/+1639
integration
2012-01-16Merge branch 'for-chris' of git://repo.or.cz/linux-btrfs-devel into integrationChris Mason6-226/+280
Conflicts: fs/btrfs/volumes.c Signed-off-by: Chris Mason <chris.mason@oracle.com>
2012-01-16Merge branch 'restriper' of git://github.com/idryomov/btrfs-unstable into ↵Chris Mason8-98/+1385
integration
2012-01-16Btrfs: add balance progress reportingIlya Dryomov4-5/+84
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-01-16Btrfs: allow for resuming restriper after it was pausedIlya Dryomov1-0/+15
Recognize BTRFS_BALANCE_RESUME flag passed from userspace. We use the same heuristics used when recovering balance after a crash to try to start where we left off last time. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-01-16Btrfs: allow for canceling restriperIlya Dryomov6-3/+53
Implement an ioctl for canceling restriper. Currently we wait until relocation of the current block group is finished, in future this can be done by triggering a commit. Balance item is deleted and no memory about the interrupted balance is kept. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-01-16Btrfs: allow for pausing restriperIlya Dryomov6-3/+94
Implement an ioctl for pausing restriper. This pauses the relocation, but balance is still considered to be "in progress": balance item is not deleted, other volume operations cannot be started, etc. If paused in the middle of profile changing operation we will continue making allocations with the target profile. Add a hook to close_ctree() to pause restriper and free its data structures on unmount. (It's safe to unmount when restriper is in "paused" state, we will resume with the same parameters on the next mount) Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-01-16Btrfs: add skip_balance mount optionIlya Dryomov3-5/+17
Since restriper kthread starts involuntarily on mount and can suck cpu and memory bandwidth add a mount option to forcefully skip it. The restriper in that case hangs around in paused state and can be resumed from userspace when it's convenient. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-01-16Btrfs: recover balance on mountIlya Dryomov3-2/+139
On mount, if balance item is found, resume balance in a separate kernel thread. Try to be smart to continue roughly where previous balance (or convert) was interrupted. For chunk types that were being converted to some profile we turn on soft convert, in case of a simple balance we turn on usage filter and relocate only less-than-90%-full chunks of that type. These are just heuristics but they help quite a bit, and can be improved in future. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-01-16Btrfs: save balance parameters to diskIlya Dryomov2-1/+231
Introduce a new btree objectid for storing balance item. The reason is to be able to resume restriper after a crash with the same parameters. Balance item has a very high objectid and goes into tree of tree roots. The key for the new item is as follows: [ BTRFS_BALANCE_OBJECTID ; BTRFS_BALANCE_ITEM_KEY ; 0 ] Older kernels simply ignore it so it's safe to mount with an older kernel and then go back to the newer one. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-01-16Btrfs: soft profile changing mode (aka soft convert)Ilya Dryomov2-0/+29
When doing convert from one profile to another if soft mode is on restriper won't touch chunks that already have the profile we are converting to. This is useful if e.g. half of the FS was converted earlier. The soft mode switch is (like every other filter) per-type. This means that we can convert for example meta chunks the "hard" way while converting data chunks selectively with soft switch. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-01-16Btrfs: implement online profile changingIlya Dryomov3-1/+129
Profile changing is done by launching a balance with BTRFS_BALANCE_CONVERT bits set and target fields of respective btrfs_balance_args structs initialized. Profile reducing code in this case will pick restriper's target profile if it's available instead of doing a blind reduce. If target profile is not yet available it goes back to a plain reduce. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-01-16Btrfs: do not reduce profile in do_chunk_alloc()Ilya Dryomov2-1/+19
Every caller of do_chunk_alloc() feeds it the reduced allocation profile, so stop trying to reduce it one more time. Instead check the validity of the passed profile. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-01-16Btrfs: virtual address space subset filterIlya Dryomov2-0/+21
Select chunks which have at least one byte located inside a given [vstart, vend) virtual address space range. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-01-16Btrfs: devid subset filterIlya Dryomov2-0/+47
Select chunks which have at least one byte of at least one stripe located on a device with devid X in a given [pstart,pend) physical address range. This filter only works when devid filter is turned on. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-01-16Btrfs: devid filterIlya Dryomov2-0/+24
Relocate chunks which have at least one stripe located on a device with devid X. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-01-16Btrfs: usage filterIlya Dryomov2-0/+37
Select chunks that are less than X percent full. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-01-16Btrfs: profiles filterIlya Dryomov2-0/+28
Select chunks based on a given profile mask. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-01-16Btrfs: add basic infrastructure for selective balancingIlya Dryomov3-2/+71
This allows to have a separate set of filters for each chunk type (data,meta,sys). The code however is generic and switch on chunk type is only done once. This commit also adds a type filter: it allows to balance for example meta and system chunks w/o touching data ones. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-01-16Btrfs: add basic restriper infrastructureIlya Dryomov6-41/+281
Add basic restriper infrastructure: extended balancing ioctl and all related ioctl data structures, add data structure for tracking restriper's state to fs_info, etc. The semantics of the old balancing ioctl are fully preserved. Explicitly disallow any volume operations when balance is in progress. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-01-16Btrfs: make avail_*_alloc_bits fields dynamicIlya Dryomov1-0/+20
Currently when new chunks are created respective avail_alloc_bits field is updated to reflect profiles of all chunks present in the system. However when chunks are removed profile bits are never cleared. This patch clears profile bit of respective avail_alloc_bits field when the last chunk with that profile is removed. Restriper needs this to properly operate when "downgrading". Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-01-16Btrfs: add BTRFS_AVAIL_ALLOC_BIT_SINGLE bitIlya Dryomov2-9/+36
Right now on-disk BTRFS_BLOCK_GROUP_* profile bits are used for avail_{data,metadata,system}_alloc_bits fields, which gather info about available allocation profiles in the FS. When chunk is created or read from disk, its profile is OR'ed with the corresponding avail_alloc_bits field. Since SINGLE is denoted by 0 in the on-disk format, currently there is no way to tell when such chunks become avaialble. Restriper needs that information, so add a separate bit for SINGLE profile. This bit is going to be in-memory only, it should never be written out to disk, so it's not a disk format change. However to avoid remappings in future, reserve corresponding on-disk bit. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-01-16Btrfs: introduce masks for chunk type and profileIlya Dryomov3-27/+22
Chunk's type and profile are encoded in u64 flags field. Introduce masks to easily access them. Also fix the type of BTRFS_BLOCK_GROUP_* constants, it should be ULL. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-01-16Btrfs: get rid of *_alloc_profile fieldsIlya Dryomov4-16/+6
{data,metadata,system}_alloc_profile fields have been unused for a long time now. Get rid of them. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2012-01-12mm: compaction: introduce sync-light migration for use by compactionMel Gorman1-2/+3
This patch adds a lightweight sync migrate operation MIGRATE_SYNC_LIGHT mode that avoids writing back pages to backing storage. Async compaction maps to MIGRATE_ASYNC while sync compaction maps to MIGRATE_SYNC_LIGHT. For other migrate_pages users such as memory hotplug, MIGRATE_SYNC is used. This avoids sync compaction stalling for an excessive length of time, particularly when copying files to a USB stick where there might be a large number of dirty pages backed by a filesystem that does not support ->writepages. [aarcange@redhat.com: This patch is heavily based on Andrea's work] [akpm@linux-foundation.org: fix fs/nfs/write.c build] [akpm@linux-foundation.org: fix fs/btrfs/disk-io.c build] Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Dave Jones <davej@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Andy Isaacson <adi@hexapodia.org> Cc: Nai Xia <nai.xia@gmail.com> Cc: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12mm: compaction: determine if dirty pages can be migrated without blocking ↵Mel Gorman1-2/+2
within ->migratepage Asynchronous compaction is used when allocating transparent hugepages to avoid blocking for long periods of time. Due to reports of stalling, there was a debate on disabling synchronous compaction but this severely impacted allocation success rates. Part of the reason was that many dirty pages are skipped in asynchronous compaction by the following check; if (PageDirty(page) && !sync && mapping->a_ops->migratepage != migrate_page) rc = -EBUSY; This skips over all mapping aops using buffer_migrate_page() even though it is possible to migrate some of these pages without blocking. This patch updates the ->migratepage callback with a "sync" parameter. It is the responsibility of the callback to fail gracefully if migration would block. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Dave Jones <davej@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Andy Isaacson <adi@hexapodia.org> Cc: Nai Xia <nai.xia@gmail.com> Cc: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>