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path: root/drivers/md/dm-cache-policy-mq.c
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2013-11-12dm cache: resolve small nits and improve DocumentationMike Snitzer1-1/+1
Document passthrough mode, cache shrinking, and cache invalidation. Also, use strcasecmp() and hlist_unhashed(). Reported-by: Alasdair G Kergon <agk@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-11dm cache: add remove_cblock method to policy interfaceJoe Thornber1-0/+35
Implement policy_remove_cblock() and add remove_cblock method to the mq policy. These methods will be used by the following cache block invalidation patch which adds the 'invalidate_cblocks' message to the cache core. Also, update some comments in dm-cache-policy.h Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-11dm cache policy mq: reduce memory requirementsJoe Thornber1-312/+231
Rather than storing the cblock in each cache entry, we allocate all entries in an array and infer the cblock from the entry position. Saves 4 bytes of memory per cache block. In addition, this gives us an easy way of looking up cache entries by cblock. We no longer need to keep an explicit bitset to track which cblocks have been allocated. And no searching is needed to find free cblocks. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-10dm cache: be much more aggressive about promoting writes to discarded blocksJoe Thornber1-21/+63
Previously these promotions only got priority if there were unused cache blocks. Now we give them priority if there are any clean blocks in the cache. The fio_soak_test in the device-mapper-test-suite now gives uniform performance across subvolumes (~16 seconds). Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-10dm cache policy mq: implement writeback_work() and mq_{set,clear}_dirty()Joe Thornber1-19/+128
There are now two multiqueues for in cache blocks. A clean one and a dirty one. writeback_work comes from the dirty one. Demotions come from the clean one. There are two benefits: - Performance improvement, since demoting a clean block is a noop. - The cache cleans itself when io load is light. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-10dm cache policy mq: a few small fixesJoe Thornber1-10/+12
Rename takeout_queue to concat_queue. Fix a harmless bug in mq policies pop() function. Currently pop() always succeeds, with up coming changes this wont be the case. Fix typo in comment above pre_cache_to_cache prototype. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-11-10dm cache policy mq: protect residency method with existing mutexJoe Thornber1-2/+6
It is safe to use a mutex in mq_residency() at this point since it is only called from ioctl context. But future-proof mq_residency() by using might_sleep() to catch new contexts that cannot sleep. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-08-16dm cache: avoid conflicting remove_mapping() in mq policyGeert Uytterhoeven1-9/+7
On sparc32, which includes <linux/swap.h> from <asm/pgtable_32.h>: drivers/md/dm-cache-policy-mq.c:962:13: error: conflicting types for 'remove_mapping' include/linux/swap.h:285:12: note: previous declaration of 'remove_mapping' was here As mq_remove_mapping() already exists, and the local remove_mapping() is used only once, inline it manually to avoid the conflict. Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair Kergon <agk@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2013-03-20dm cache: policy change version from string to integer setMike Snitzer1-2/+6
Separate dm cache policy version string into 3 unsigned numbers corresponding to major, minor and patchlevel and store them at the end of the on-disk metadata so we know which version of the policy generated the hints in case a future version wants to use them differently. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-02dm cache: add mq policyJoe Thornber1-0/+1195
A cache policy that uses a multiqueue ordered by recent hit count to select which blocks should be promoted and demoted. This is meant to be a general purpose policy. It prioritises reads over writes. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>