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Paul Dagnelie
f664f1ee7f
Currently, sequential async write workloads spend a lot of time contending on the dn_struct_rwlock. This lock is responsible for protecting the entire block tree below it; this naturally results in some serialization during heavy write workloads. This can be resolved by having per-dbuf locking, which will allow multiple writers in the same object at the same time. We introduce a new rwlock, the db_rwlock. This lock is responsible for protecting the contents of the dbuf that it is a part of; when reading a block pointer from a dbuf, you hold the lock as a reader. When writing data to a dbuf, you hold it as a writer. This allows multiple threads to write to different parts of a file at the same time. Reviewed by: Brad Lewis <brad.lewis@delphix.com> Reviewed by: Matt Ahrens matt@delphix.com Reviewed by: George Wilson george.wilson@delphix.com Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Paul Dagnelie <pcd@delphix.com> External-issue: DLPX-52564 External-issue: DLPX-53085 External-issue: DLPX-57384 Closes #8946