Hi all, I just send the scripts to test these series here. Cheers, Shida zhangshida <starzhangzsd@xxxxxxxxx> 于2024年11月4日周一 09:44写道： > > From: Shida Zhang <zhangshida@xxxxxxxxxx> > > Hi all, > > Recently, we've been encounter xfs problems from our two > major users continuously. > They are all manifested as the same phonomenon: a xfs > filesystem can't touch new file when there are nearly > half of the available space even with sparse inode enabled. > > It turns out that the filesystem is too fragmented to have > enough continuous free space to create a new file. > > Life still has to goes on. > But from our users' perspective, worse than the situation > that xfs is hard to use is that xfs is non-able to use, > since even one single file can't be created now. > > So we try to introduce a new space allocation algorithm to > solve this. > > To achieve that, we try to propose a new concept: > Allocation Fields, where its name is borrowed from the > mathmatical concepts(Groups,Rings,Fields), will be > abbrivated as AF in the rest of the article. > > what is a AF? > An one-pic-to-say-it-all version of explaination: > > |<--------+ af 0 +-------->|<--+ af 1 +-->| af 2| > |------------------------------------------------+ > | ag 0 | ag 1 | ag 2 | ag 3| ag 4 | ag 5 | ag 6 | > +------------------------------------------------+ > > A text-based definition of AF: > 1.An AF is a incore-only concept comparing with the on-disk > AG concept. > 2.An AF is consisted of a continuous series of AGs. > 3.Lower AFs will NEVER go to higher AFs for allocation if > it can complete it in the current AF. > > Rule 3 can serve as a barrier between the AF to slow down > the over-speed extending of fragmented pieces. > > With these patches applied, the code logic will be exactly > the same as the original code logic, unless you run with the > extra mount opiton. For example: > mount -o af1=1 $dev $mnt > > That will change the default AF layout: > > |<--------+ af 0 +--------->| > |---------------------------- > | ag 0 | ag 1 | ag 2 | ag 3 | > +---------------------------- > > to : > > |<-----+ af 0 +----->|<af 1>| > |---------------------------- > | ag 0 | ag 1 | ag 2 | ag 3 | > +---------------------------- > > So the 'af1=1' here means the start agno is one ag away from > the m_sb.agcount. > > We did some tests verify it. You can verify it yourself > by running the following the command: > > 1. Create an 1g sized img file and formated it as xfs: > dd if=/dev/zero of=test.img bs=1M count=1024 > mkfs.xfs -f test.img > sync > 2. Make a mount directory: > mkdir mnt > 3. Run the auto_frag.sh script, which will call another scripts > frag.sh. These scripts will be attached in the mail. > To enable the AF, run: > ./auto_frag.sh 1 > To disable the AF, run: > ./auto_frag.sh 0 > > Please feel free to communicate with us if you have any thoughts > about these problems. > > Cheers, > Shida > > > Shida Zhang (5): > xfs: add two wrappers for iterating ags in a AF > xfs: add two mp member to record the alloction field layout > xfs: add mount options as a way to change the AF layout > xfs: add infrastructure to support AF allocation algorithm > xfs: modify the logic to comply with AF rules > > fs/xfs/libxfs/xfs_ag.h | 17 ++++++++++++ > fs/xfs/libxfs/xfs_alloc.c | 20 ++++++++++++++- > fs/xfs/libxfs/xfs_alloc.h | 2 ++ > fs/xfs/libxfs/xfs_bmap.c | 47 ++++++++++++++++++++++++++++++++-- > fs/xfs/libxfs/xfs_bmap_btree.c | 2 ++ > fs/xfs/xfs_mount.h | 3 +++ > fs/xfs/xfs_super.c | 12 ++++++++- > 7 files changed, 99 insertions(+), 4 deletions(-) > > -- > 2.33.0 >
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