- 23 2月, 2013 1 次提交
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由 Jan Kara 提交于
Running AIO is pinning inode in memory using file reference. Once AIO is completed using aio_complete(), file reference is put and inode can be freed from memory. So we have to be sure that calling aio_complete() is the last thing we do with the inode. CC: Christoph Hellwig <hch@infradead.org> CC: Jens Axboe <axboe@kernel.dk> CC: Jeff Moyer <jmoyer@redhat.com> CC: stable@vger.kernel.org Acked-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NJan Kara <jack@suse.cz> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 30 11月, 2012 1 次提交
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由 Linus Torvalds 提交于
Since directio can work on a raw block device, and the block size of the device can change under it, we need to do the same thing that fs/buffer.c now does: read the block size a single time, using ACCESS_ONCE(). Reading it multiple times can get different results, which will then confuse the code because it actually encodes the i_blksize in relationship to the underlying logical blocksize. Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 09 8月, 2012 1 次提交
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由 Fengguang Wu 提交于
Move unplugging for direct I/O from around ->direct_IO() down to do_blockdev_direct_IO(). This implicitly adds plugging for direct writes. CC: Li Shaohua <shli@fusionio.com> Acked-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NWu Fengguang <fengguang.wu@intel.com> Signed-off-by: NJens Axboe <axboe@kernel.dk>
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- 14 7月, 2012 1 次提交
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由 Julia Lawall 提交于
READ is 0, so the result of the bit-and operation is 0. Rewrite with == as done elsewhere in the same file. This problem was found using Coccinelle (http://coccinelle.lip6.fr/). Signed-off-by: NJulia Lawall <julia@diku.dk> Reviewed-by: NJeff Moyer <jmoyer@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 01 6月, 2012 1 次提交
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由 Trond Myklebust 提交于
Use the same mechanism as the block devices are using, but move the helper functions from fs/direct-io.c into fs/inode.c to remove the dependency on CONFIG_BLOCK. Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Fred Isaman <iisaman@netapp.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 24 2月, 2012 1 次提交
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由 Anton Altaparmakov 提交于
With kernel 3.1, Christoph removed i_alloc_sem and replaced it with calls (namely inode_dio_wait() and inode_dio_done()) which are EXPORT_SYMBOL_GPL() thus they cannot be used by non-GPL file systems and further inode_dio_wait() was pushed from notify_change() into the file system ->setattr() method but no non-GPL file system can make this call. That means non-GPL file systems cannot exist any more unless they do not use any VFS functionality related to reading/writing as far as I can tell or at least as long as they want to implement direct i/o. Both Linus and Al (and others) have said on LKML that this breakage of the VFS API should not have happened and that the change was simply missed as it was not documented in the change logs of the patches that did those changes. This patch changes the two function exports in question to be EXPORT_SYMBOL() thus restoring the VFS API as it used to be - accessible for all modules. Christoph, who introduced the two functions and exported them GPL-only is CC-ed on this patch to give him the opportunity to object to the symbols being changed in this manner if he did indeed intend them to be GPL-only and does not want them to become available to all modules. Signed-off-by: NAnton Altaparmakov <anton@tuxera.com> CC: Christoph Hellwig <hch@infradead.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 13 1月, 2012 2 次提交
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由 Andi Kleen 提交于
Some investigation of a transaction processing workload showed that a major consumer of cycles in __blockdev_direct_IO is the cache miss while accessing the block size. This is because it has to walk the chain from block_dev to gendisk to queue. The block size is needed early on to check alignment and sizes. It's only done if the check for the inode block size fails. But the costly block device state is unconditionally fetched. - Reorganize the code to only fetch block dev state when actually needed. Then do a prefetch on the block dev early on in the direct IO path. This is worth it, because there is substantial code run before we actually touch the block dev now. - I also added some unlikelies to make it clear the compiler that block device fetch code is not normally executed. This gave a small, but measurable improvement on a large database benchmark (about 0.3%) [akpm@linux-foundation.org: coding-style fixes] [sfr@canb.auug.org.au: using prefetch requires including prefetch.h] Signed-off-by: NAndi Kleen <ak@linux.intel.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Tao Ma 提交于
In get_more_blocks(), we use dio_count to calcuate fs_count and do some tricky things to increase fs_count if dio_count isn't aligned. But actually it still has some corner cases that can't be coverd. See the following example: dio_write foo -s 1024 -w 4096 (direct write 4096 bytes at offset 1024). The same goes if the offset isn't aligned to fs_blocksize. In this case, the old calculation counts fs_count to be 1, but actually we will write into 2 different blocks (if fs_blocksize=4096). The old code just works, since it will call get_block twice (and may have to allocate and create extents twice for filesystems like ext4). So we'd better call get_block just once with the proper fs_count. Signed-off-by: NTao Ma <boyu.mt@taobao.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 28 10月, 2011 7 次提交
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由 Andi Kleen 提交于
This doesn't change anything for the compiler, but hch thought it would make the code clearer. I moved the reference counting into its own little inline. Signed-off-by: NAndi Kleen <ak@linux.intel.com> Acked-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NChristoph Hellwig <hch@lst.de>
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由 Andi Kleen 提交于
Add inlines to all the submission path functions. While this increases code size it also gives gcc a lot of optimization opportunities in this critical hotpath. In particular -- together with some other changes -- this allows gcc to get rid of the unnecessary clearing of sdio at the beginning and optimize the messy parameter passing. Any non inlining of a function which takes a sdio parameter would break this optimization because they cannot be done if the address of a structure is taken. Note that benefits are only seen with CONFIG_OPTIMIZE_INLINING and CONFIG_CC_OPTIMIZE_FOR_SIZE both set to off. This gives about 2.2% improvement on a large database benchmark with a high IOPS rate. Signed-off-by: NAndi Kleen <ak@linux.intel.com> Signed-off-by: NChristoph Hellwig <hch@lst.de>
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由 Andi Kleen 提交于
Only a single b_private field in the map_bh buffer head is needed after the submission path. Move map_bh separately to avoid storing this information in the long term slab. This avoids the weird 104 byte hole in struct dio_submit which also needed to be memseted early. Signed-off-by: NAndi Kleen <ak@linux.intel.com> Signed-off-by: NChristoph Hellwig <hch@lst.de>
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由 Andi Kleen 提交于
A direct slab call is slightly faster than kmalloc and can be better cached per CPU. It also avoids rounding to the next kmalloc slab. In addition this enforces cache line alignment for struct dio to avoid any false sharing. Signed-off-by: NAndi Kleen <ak@linux.intel.com> Acked-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NChristoph Hellwig <hch@lst.de>
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由 Andi Kleen 提交于
Fix most problems reported by pahole. There is still a weird 104 byte hole after map_bh. I'm not sure what causes this. Signed-off-by: NAndi Kleen <ak@linux.intel.com> Acked-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NChristoph Hellwig <hch@lst.de>
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由 Andi Kleen 提交于
There's nothing on the stack, even before my changes. Signed-off-by: NAndi Kleen <ak@linux.intel.com> Acked-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NChristoph Hellwig <hch@lst.de>
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由 Andi Kleen 提交于
This large, but largely mechanic, patch moves all fields in struct dio that are only used in the submission path into a separate on stack data structure. This has the advantage that the memory is very likely cache hot, which is not guaranteed for memory fresh out of kmalloc. This also gives gcc more optimization potential because it can easier determine that there are no external aliases for these variables. The sdio initialization is a initialization now instead of memset. This allows gcc to break sdio into individual fields and optimize away unnecessary zeroing (after all the functions are inlined) Signed-off-by: NAndi Kleen <ak@linux.intel.com> Acked-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NChristoph Hellwig <hch@lst.de>
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- 27 7月, 2011 1 次提交
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由 Arun Sharma 提交于
This allows us to move duplicated code in <asm/atomic.h> (atomic_inc_not_zero() for now) to <linux/atomic.h> Signed-off-by: NArun Sharma <asharma@fb.com> Reviewed-by: NEric Dumazet <eric.dumazet@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Miller <davem@davemloft.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: NMike Frysinger <vapier@gentoo.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 21 7月, 2011 4 次提交
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由 Christoph Hellwig 提交于
For filesystems that delay their end_io processing we should keep our i_dio_count until the the processing is done. Enable this by moving the inode_dio_done call to the end_io handler if one exist. Note that the actual move to the workqueue for ext4 and XFS is not done in this patch yet, but left to the filesystem maintainers. At least for XFS it's not needed yet either as XFS has an internal equivalent to i_dio_count. Signed-off-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Christoph Hellwig 提交于
Maintain i_dio_count for all filesystems, not just those using DIO_LOCKING. This these filesystems to also protect truncate against direct I/O requests by using common code. Right now the only non-DIO_LOCKING filesystem that appears to do so is XFS, which uses an opencoded variant of the i_dio_count scheme. Behaviour doesn't change for filesystems never calling inode_dio_wait. For ext4 behaviour changes when using the dioread_nonlock option, which previously was missing any protection between truncate and direct I/O reads. For ocfs2 that handcrafted i_dio_count manipulations are replaced with the common code now enable. Signed-off-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Christoph Hellwig 提交于
i_alloc_sem is a rather special rw_semaphore. It's the last one that may be released by a non-owner, and it's write side is always mirrored by real exclusion. It's intended use it to wait for all pending direct I/O requests to finish before starting a truncate. Replace it with a hand-grown construct: - exclusion for truncates is already guaranteed by i_mutex, so it can simply fall way - the reader side is replaced by an i_dio_count member in struct inode that counts the number of pending direct I/O requests. Truncate can't proceed as long as it's non-zero - when i_dio_count reaches non-zero we wake up a pending truncate using wake_up_bit on a new bit in i_flags - new references to i_dio_count can't appear while we are waiting for it to read zero because the direct I/O count always needs i_mutex (or an equivalent like XFS's i_iolock) for starting a new operation. This scheme is much simpler, and saves the space of a spinlock_t and a struct list_head in struct inode (typically 160 bits on a non-debug 64-bit system). Signed-off-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Christoph Hellwig 提交于
Reject zero sized reads as soon as we know our I/O length, and don't borther with locks or allocations that might have to be cleaned up otherwise. Signed-off-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 10 3月, 2011 2 次提交
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由 Jens Axboe 提交于
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: NJens Axboe <jaxboe@fusionio.com>
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由 Jens Axboe 提交于
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: NJens Axboe <jaxboe@fusionio.com>
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- 21 1月, 2011 1 次提交
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由 David Dillow 提交于
When using devices that support max_segments > BIO_MAX_PAGES (256), direct IO tries to allocate a bio with more pages than allowed, which leads to an oops in dio_bio_alloc(). Clamp the request to the supported maximum, and change dio_bio_alloc() to reflect that bio_alloc() will always return a bio when called with __GFP_WAIT and a valid number of vectors. [akpm@linux-foundation.org: remove redundant BUG_ON()] Signed-off-by: NDavid Dillow <dillowda@ornl.gov> Reviewed-by: NJeff Moyer <jmoyer@redhat.com> Cc: <stable@kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 19 1月, 2011 1 次提交
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由 Namhyung Kim 提交于
Signed-off-by: NNamhyung Kim <namhyung@gmail.com> Cc: Jiri Kosina <trivial@kernel.org> Signed-off-by: NJiri Kosina <jkosina@suse.cz>
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- 27 10月, 2010 1 次提交
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由 Edward Shishkin 提交于
Fix up truncation (ssize_t->int). This only matters with >2G reads/writes, which the kernel doesn't permit. Signed-off-by: NEdward Shishkin <edward@redhat.com> Reviewed-by: NChristoph Hellwig <hch@lst.de> Acked-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 10 9月, 2010 1 次提交
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由 Jeff Moyer 提交于
commit c2c6ca41 (direct-io: do not merge logically non-contiguous requests) introduced a bug whereby all O_DIRECT I/Os were submitted a page at a time to the block layer. The problem is that the code expected dio->block_in_file to correspond to the current page in the dio. In fact, it corresponds to the previous page submitted via submit_page_section. This was purely an oversight, as the dio->cur_page_fs_offset field was introduced for just this purpose. This patch simply uses the correct variable when calculating whether there is a mismatch between contiguous logical blocks and contiguous physical blocks (as described in the comments). I also switched the if conditional following this check to an else if, to ensure that we never call dio_bio_submit twice for the same dio (in theory, this should not happen, anyway). I've tested this by running blktrace and verifying that a 64KB I/O was submitted as a single I/O. I also ran the patched kernel through xfstests' aio tests using xfs, ext4 (with 1k and 4k block sizes) and btrfs and verified that there were no regressions as compared to an unpatched kernel. Signed-off-by: NJeff Moyer <jmoyer@redhat.com> Acked-by: NJosef Bacik <jbacik@redhat.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Chris Mason <chris.mason@oracle.com> Cc: <stable@kernel.org> [2.6.35.x] Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 10 8月, 2010 1 次提交
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由 Christoph Hellwig 提交于
Move the call to vmtruncate to get rid of accessive blocks to the callers in prepearation of the new truncate calling sequence. This was only done for DIO_LOCKING filesystems, so the __blockdev_direct_IO_newtrunc variant was not needed anyway. Get rid of blockdev_direct_IO_no_locking and its _newtrunc variant while at it as just opencoding the two additional paramters is shorted than the name suffix. Signed-off-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 27 7月, 2010 2 次提交
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由 Christoph Hellwig 提交于
Filesystems with unwritten extent support must not complete an AIO request until the transaction to convert the extent has been commited. That means the aio_complete calls needs to be moved into the ->end_io callback so that the filesystem can control when to call it exactly. This makes a bit of a mess out of dio_complete and the ->end_io callback prototype even more complicated. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
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由 Christoph Hellwig 提交于
Filesystems with unwritten extent support must not complete an AIO request until the transaction to convert the extent has been commited. That means the aio_complete calls needs to be moved into the ->end_io callback so that the filesystem can control when to call it exactly. This makes a bit of a mess out of dio_complete and the ->end_io callback prototype even more complicated. Signed-off-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NJan Kara <jack@suse.cz> Signed-off-by: NAlex Elder <aelder@sgi.com>
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- 28 5月, 2010 1 次提交
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由 npiggin@suse.de 提交于
Introduce a new truncate calling sequence into fs/mm subsystems. Rather than setattr > vmtruncate > truncate, have filesystems call their truncate sequence from ->setattr if filesystem specific operations are required. vmtruncate is deprecated, and truncate_pagecache and inode_newsize_ok helpers introduced previously should be used. simple_setattr is introduced for simple in-ram filesystems to implement the new truncate sequence. Eventually all filesystems should be converted to implement a setattr, and the default code in notify_change should go away. simple_setsize is also introduced to perform just the ATTR_SIZE portion of simple_setattr (ie. changing i_size and trimming pagecache). To implement the new truncate sequence: - filesystem specific manipulations (eg freeing blocks) must be done in the setattr method rather than ->truncate. - vmtruncate can not be used by core code to trim blocks past i_size in the event of write failure after allocation, so this must be performed in the fs code. - convert usage of helpers block_write_begin, nobh_write_begin, cont_write_begin, and *blockdev_direct_IO* to use _newtrunc postfixed variants. These avoid calling vmtruncate to trim blocks (see previous). - inode_setattr should not be used. generic_setattr is a new function to be used to copy simple attributes into the generic inode. - make use of the better opportunity to handle errors with the new sequence. Big problem with the previous calling sequence: the filesystem is not called until i_size has already changed. This means it is not allowed to fail the call, and also it does not know what the previous i_size was. Also, generic code calling vmtruncate to truncate allocated blocks in case of error had no good way to return a meaningful error (or, for example, atomically handle block deallocation). Cc: Christoph Hellwig <hch@lst.de> Acked-by: NJan Kara <jack@suse.cz> Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 25 5月, 2010 2 次提交
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由 Josef Bacik 提交于
Btrfs cannot handle having logically non-contiguous requests submitted. For example if you have Logical: [0-4095][HOLE][8192-12287] Physical: [0-4095] [4096-8191] Normally the DIO code would put these into the same BIO's. The problem is we need to know exactly what offset is associated with what BIO so we can do our checksumming and unlocking properly, so putting them in the same BIO doesn't work. So add another check where we submit the current BIO if the physical blocks are not contigous OR the logical blocks are not contiguous. Signed-off-by: NJosef Bacik <josef@redhat.com> Signed-off-by: NChris Mason <chris.mason@oracle.com>
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由 Josef Bacik 提交于
Because BTRFS can do RAID and such, we need our own submit hook so we can setup the bio's in the correct fashion, and handle checksum errors properly. So there are a few changes here 1) The submit_io hook. This is straightforward, just call this instead of submit_bio. 2) Allow the fs to return -ENOTBLK for reads. Usually this has only worked for writes, since writes can fallback onto buffered IO. But BTRFS needs the option of falling back on buffered IO if it encounters a compressed extent, since we need to read the entire extent in and decompress it. So if we get -ENOTBLK back from get_block we'll return back and fallback on buffered just like the write case. I've tested these changes with fsx and everything seems to work. Thanks, Signed-off-by: NJosef Bacik <josef@redhat.com> Signed-off-by: NChris Mason <chris.mason@oracle.com>
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- 17 12月, 2009 2 次提交
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由 Al Viro 提交于
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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由 Christoph Hellwig 提交于
Currently the locking in blockdev_direct_IO is a mess, we have three different locking types and very confusing checks for some of them. The most complicated one is DIO_OWN_LOCKING for reads, which happens to not actually be used. This patch gets rid of the DIO_OWN_LOCKING - as mentioned above the read case is unused anyway, and the write side is almost identical to DIO_NO_LOCKING. The difference is that DIO_NO_LOCKING always sets the create argument for the get_blocks callback to zero, but we can easily move that to the actual get_blocks callbacks. There are four users of the DIO_NO_LOCKING mode: gfs already ignores the create argument and thus is fine with the new version, ocfs2 only errors out if create were ever set, and we can remove this dead code now, the block device code only ever uses create for an error message if we are fully beyond the device which can never happen, and last but not least XFS will need the new behavour for writes. Now we can replace the lock_type variable with a flags one, where no flag means the DIO_NO_LOCKING behaviour and DIO_LOCKING is kept as the first flag. Separate out the check for not allowing to fill holes into a separate flag, although for now both flags always get set at the same time. Also revamp the documentation of the locking scheme to actually make sense. Signed-off-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 16 12月, 2009 2 次提交
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由 Christoph Hellwig 提交于
Currently the locking in blockdev_direct_IO is a mess, we have three different locking types and very confusing checks for some of them. The most complicated one is DIO_OWN_LOCKING for reads, which happens to not actually be used. This patch gets rid of the DIO_OWN_LOCKING - as mentioned above the read case is unused anyway, and the write side is almost identical to DIO_NO_LOCKING. The difference is that DIO_NO_LOCKING always sets the create argument for the get_blocks callback to zero, but we can easily move that to the actual get_blocks callbacks. There are four users of the DIO_NO_LOCKING mode: gfs already ignores the create argument and thus is fine with the new version, ocfs2 only errors out if create were ever set, and we can remove this dead code now, the block device code only ever uses create for an error message if we are fully beyond the device which can never happen, and last but not least XFS will need the new behavour for writes. Now we can replace the lock_type variable with a flags one, where no flag means the DIO_NO_LOCKING behaviour and DIO_LOCKING is kept as the first flag. Separate out the check for not allowing to fill holes into a separate flag, although for now both flags always get set at the same time. Also revamp the documentation of the locking scheme to actually make sense. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: NChristoph Hellwig <hch@lst.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Badari Pulavarty <pbadari@us.ibm.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Zach Brown <zach.brown@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Alex Elder <aelder@sgi.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <joel.becker@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jeff Moyer 提交于
Intel reported a performance regression caused by the following commit: commit 848c4dd5 Author: Zach Brown <zach.brown@oracle.com> Date: Mon Aug 20 17:12:01 2007 -0700 dio: zero struct dio with kzalloc instead of manually This patch uses kzalloc to zero all of struct dio rather than manually trying to track which fields we rely on being zero. It passed aio+dio stress testing and some bug regression testing on ext3. This patch was introduced by Linus in the conversation that lead up to Badari's minimal fix to manually zero .map_bh.b_state in commit: 6a648fa7 It makes the code a bit smaller. Maybe a couple fewer cachelines to load, if we're lucky: text data bss dec hex filename 3285925 568506 1304616 5159047 4eb887 vmlinux 3285797 568506 1304616 5158919 4eb807 vmlinux.patched I was unable to measure a stable difference in the number of cpu cycles spent in blockdev_direct_IO() when pushing aio+dio 256K reads at ~340MB/s. So the resulting intent of the patch isn't a performance gain but to avoid exposing ourselves to the risk of finding another field like .map_bh.b_state where we rely on zeroing but don't enforce it in the code. Zach surmised that zeroing out the page array was what caused most of the problem, and suggested the approach taken in the attached patch for resolving the issue. Intel re-tested with this patch and saw a 0.6% performance gain (the original regression was 0.5%). [akpm@linux-foundation.org: add comment] Signed-off-by: NJeff Moyer <jmoyer@redhat.com> Acked-by: NZach Brown <zach.brown@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 26 11月, 2009 1 次提交
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由 Vivek Goyal 提交于
There seems to be a regression in direct write path due to following commit in for-2.6.33 branch of block tree. commit 1af60fbd Author: Jeff Moyer <jmoyer@redhat.com> Date: Fri Oct 2 18:56:53 2009 -0400 block: get rid of the WRITE_ODIRECT flag Marking direct writes as WRITE_SYNC_PLUG instead of WRITE_ODIRECT, sets the NOIDLE flag in bio and hence in request. This tells CFQ to not expect more request from the queue and not idle on it (despite the fact that queue's think time is less and it is not seeky). So direct writers lose big time when competing with sequential readers. Using fio, I have run one direct writer and two sequential readers and following are the results with 2.6.32-rc7 kernel and with for-2.6.33 branch. Test ==== 1 direct writer and 2 sequential reader running simultaneously. [global] directory=/mnt/sdc/fio/ runtime=10 [seqwrite] rw=write size=4G direct=1 [seqread] rw=read size=2G numjobs=2 2.6.32-rc7 ========== direct writes: aggrb=2,968KB/s readers : aggrb=101MB/s for-2.6.33 branch ================= direct write: aggrb=19KB/s readers aggrb=137MB/s This patch brings back the WRITE_ODIRECT flag, with the difference that we don't set the BIO_RW_UNPLUG flag so that device is not unplugged after submission of request and an explicit unplug from submitter is required. That way we fix the jeff's issue of not enough merging taking place in aio path as well as make sure direct writes get their fair share. After the fix ============= for-2.6.33 + fix ---------------- direct writes: aggrb=2,728KB/s reads: aggrb=103MB/s Thanks Vivek Signed-off-by: NVivek Goyal <vgoyal@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 28 10月, 2009 2 次提交
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由 Jeff Moyer 提交于
Hi, Some workloads issue batches of small I/O, and the performance is poor due to the call to blk_run_address_space for every single iocb. Nathan Roberts pointed this out, and suggested that by deferring this call until all I/Os in the iocb array are submitted to the block layer, we can realize some impressive performance gains (up to 30% for sequential 4k reads in batches of 16). Signed-off-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jeff Moyer 提交于
Hi, The WRITE_ODIRECT flag is only used in one place, and that code path happens to also call blk_run_address_space. The introduction of this flag, then, could result in the device being unplugged twice for every I/O. Further, with the batching changes in the next patch, we don't want an O_DIRECT write to imply a queue unplug. Signed-off-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 23 5月, 2009 1 次提交
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由 Martin K. Petersen 提交于
Until now we have had a 1:1 mapping between storage device physical block size and the logical block sized used when addressing the device. With SATA 4KB drives coming out that will no longer be the case. The sector size will be 4KB but the logical block size will remain 512-bytes. Hence we need to distinguish between the physical block size and the logical ditto. This patch renames hardsect_size to logical_block_size. Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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