- 11 Nov, 2013 40 commits
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Kent Overstreet authored
Big garbage collection rewrite; now, garbage collection uses the same mechanisms as used elsewhere for inserting/updating btree node pointers, instead of rewriting interior btree nodes in place. This makes the code significantly cleaner and less fragile, and means we can now make garbage collection incremental - it doesn't have to hold a write lock on the root of the btree for the entire duration of garbage collection. This means that there's less of a latency hit for doing garbage collection, which means we can gc more frequently (and do a better job of reclaiming from the cache), and we can coalesce across more btree nodes (improving our space efficiency). Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
Refactoring, prep work for incremental garbage collection. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
More refactoring - mostly making the interfaces more explicit about what we actually want to do. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
btree_insert_key() was open coding this, this is just refactoring. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
Trying to treat btree pointers and leaf node pointers the same way was a mistake - going to start being more explicit about the type of key/pointer we're dealing with. This is the first part of that refactoring; this patch shouldn't change any actual behaviour. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
The bucket refcount (dropped with bkey_put()) is only needed to prevent the newly allocated bucket from being garbage collected until we've added a pointer to it somewhere. But for btree node allocations, the fact that we have btree nodes locked is enough to guard against races with garbage collection. Eventually the per bucket refcount is going to be replaced with something specific to bch_alloc_sectors(). Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
Couple changes: * Consolidate bch_check_keys() and bch_check_key_order(), and move the checks that only check_key_order() could do to bch_btree_iter_next(). * Get rid of CONFIG_BCACHE_EDEBUG - now, all that code is compiled in when CONFIG_BCACHE_DEBUG is enabled, and there's now a sysfs file to flip on the EDEBUG checks at runtime. * Dropped an old not terribly useful check in rw_unlock(), and refactored/improved a some of the other debug code. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
Previously, bch_ptr_bad() could return false when there was a pointer to a nonexistant device... it only filtered out keys with PTR_CHECK_DEV pointers. This behaviour was intended for multiple cache device support; for that, just because the device for one of the pointers has gone away doesn't mean we want to filter out the rest of the pointers. But we don't yet explicitly filter/check individual pointers, so without that this behaviour was wrong - a corrupt bkey with a bad device pointer could cause us to deref a bad pointer. Doh. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
Now, the on disk data structures are in a header that can be exported to userspace - and having them all centralized is nice too. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
Just reorganizing things a bit. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
With all the recent refactoring around struct btree op struct search has gotten rather large. But we can now easily break it up in a different way - we break out struct btree_insert_op which is for inserting data into the cache, and that's now what the copying gc code uses - struct search is now specific to request.c Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
Last of the btree_map() conversions. Main visible effect is bch_btree_insert() is no longer taking a struct btree_op as an argument anymore - there's no fancy state machine stuff going on, it's just a normal function. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
When we convert bch_btree_insert() to bch_btree_map_leaf_nodes(), we won't be passing struct btree_op to bch_btree_insert() anymore - so we need a different way of returning whether there was a collision (really, a replace collision). Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
This is prep work for converting bch_btree_insert to bch_btree_map_leaf_nodes() - we have to convert all its arguments to actual arguments. Bunch of churn, but should be straightforward. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
With a the recent bcache refactoring, some of the closure code isn't needed anymore. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
This isn't used for waiting asynchronously anymore - so this is a fairly trivial refactoring. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
Eventual goal is for struct btree_op to contain only what is necessary for traversing the btree. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
There was some looping in submit_partial_cache_hit() and submit_partial_cache_hit() that isn't needed anymore - originally, we wouldn't necessarily process the full hit or miss all at once because when splitting the bio, we took into account the restrictions of the device we were sending it to. But, device bio size restrictions are now handled elsewhere, with a wrapper around generic_make_request() - so that looping has been unnecessary for awhile now and we can now do quite a bit of cleanup. And if we trim the key we're reading from to match the subset we're actually reading, we don't have to explicitly calculate bi_sector anymore. Neat. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
This is a fairly straightforward conversion, mostly reshuffling - op->lookup_done goes away, replaced by MAP_DONE/MAP_CONTINUE. And the code for handling cache hits and misses wasn't really btree code, so it gets moved to request.c. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
With the new btree_map() functions, we don't need to export the stuff needed for traversing the btree anymore. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
Lots of stuff has been open coding its own btree traversal - which is generally pretty simple code, but there are a few subtleties. This adds new new functions, bch_btree_map_nodes() and bch_btree_map_keys(), which do the traversal for you. Everything that's open coding btree traversal now (with the exception of garbage collection) is slowly going to be converted to these two functions; being able to write other code at a higher level of abstraction is a big improvement w.r.t. overall code quality. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
This simplifies the writeback flow control quite a bit - previously, it was conceptually two coroutines, refill_dirty() and read_dirty(). This makes the code quite a bit more straightforward. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
We needed a dedicated rescuer workqueue for gc anyways... and gc was conceptually a dedicated thread, just one that wasn't running all the time. Switch it to a dedicated thread to make the code a bit more straightforward. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
At one point we did do fancy asynchronous waiting stuff with bucket_wait, but that's all gone (and bucket_wait is used a lot less than it used to be). So use the standard primitives. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
We never waited on c->try_wait asynchronously, so just use the standard primitives. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
Slowly working on pruning struct btree_op - the aim is for it to only contain things that are actually necessary for traversing the btree. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
Making things less asynchronous that don't need to be - bch_journal() only has to block when the journal or journal entry is full, which is emphatically not a fast path. So make it a normal function that just returns when it finishes, to make the code and control flow easier to follow. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
More refactoring, and renaming. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
Try to improve some of the naming a bit to be more consistent, and also improve the flow of control in request_write() a bit. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
More random refactoring. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
Some refactoring - better to explicitly pass stuff around instead of having it all in the "big bag of state", struct btree_op. Going to prune struct btree_op quite a bit over time. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
This was the main point of all this refactoring - now, btree_insert_check_key() won't fail just because the leaf node happened to be full. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
We'll often end up with a list of adjacent keys to insert - because bch_data_insert() may have to fragment the data it writes. Originally, to simplify things and avoid having to deal with corner cases bch_btree_insert() would pass keys from this list one at a time to btree_insert_recurse() - mainly because the list of keys might span leaf nodes, so it was easier this way. With the btree_insert_node() refactoring, it's now a lot easier to just pass down the whole list and have btree_insert_recurse() iterate over leaf nodes until it's done. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
The flow of control in the old btree insertion code was rather - backwards; we'd recurse down the btree (in btree_insert_recurse()), and then if we needed to split the keys to be inserted into the parent node would be effectively returned up to btree_insert_recurse(), which would notice there was more work to do and finish the insertion. The main problem with this was that the full logic for btree insertion could only be used by calling btree_insert_recurse; if you'd gotten to a btree leaf some other way and had a key to insert, if it turned out that node needed to be split you were SOL. This inverts the flow of control so btree_insert_node() does _full_ btree insertion, including splitting - and takes a (leaf) btree node to insert into as a parameter. This means we can now _correctly_ handle cache misses - for cache misses, we need to insert a fake "check" key into the btree when we discover we have a cache miss - while we still have the btree locked. Previously, if the btree node was full inserting a cache miss would just fail. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
This is prep work for the reworked btree insertion code. The way we set b->parent is ugly and hacky... the problem is, when btree_split() or garbage collection splits or rewrites a btree node, the parent changes for all its (potentially already cached) children. I may change this later and add some code to look through the btree node cache and find all our cached child nodes and change the parent pointer then... Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
Checking i->seq was redundant, because since ages ago we always initialize the new bset when advancing b->written Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
Originally I got this right... except that the divides didn't use do_div(), which broke 32 bit kernels. When I went to fix that, I forgot that the raid stripe size usually isn't a power of two... doh Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
Works kind of like the ext4 setting, to panic or remount read only on errors. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
The old asynchronous discard code was really a relic from when all the allocation code was asynchronous - now that allocation runs out of a dedicated thread there's no point in keeping around all that complicated machinery. Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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Kent Overstreet authored
bch_keybuf_del() takes a spinlock that can't be taken in interrupt context - whoops. Fortunately, this code isn't enabled by default (you have to toggle a sysfs thing). Signed-off-by:
Kent Overstreet <kmo@daterainc.com>
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