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[PATCH] Kill PF_SYNCWRITE flag
A process flag to indicate whether we are doing sync io is incredibly ugly. It also causes performance problems when one does a lot of async io and then proceeds to sync it. Part of the io will go out as async, and the other part as sync. This causes a disconnect between the previously submitted io and the synced io. For io schedulers such as CFQ, this will cause us lost merges and suboptimal behaviour in scheduling. Remove PF_SYNCWRITE completely from the fsync/msync paths, and let the O_DIRECT path just directly indicate that the writes are sync by using WRITE_SYNC instead. Signed-off-by: Jens Axboe <axboe@suse.de>
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parent
271f18f102
commit
b31dc66a54
10 changed files with 20 additions and 29 deletions
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@ -331,7 +331,6 @@ long do_fsync(struct file *file, int datasync)
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goto out;
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}
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current->flags |= PF_SYNCWRITE;
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ret = filemap_fdatawrite(mapping);
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/*
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@ -346,7 +345,6 @@ long do_fsync(struct file *file, int datasync)
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err = filemap_fdatawait(mapping);
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if (!ret)
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ret = err;
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current->flags &= ~PF_SYNCWRITE;
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out:
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return ret;
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}
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