11 Sep, 2013
1 commit
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Convert the driver shrinkers to the new API. Most changes are compile
tested only because I either don't have the hardware or it's staging
stuff.FWIW, the md and android code is pretty good, but the rest of it makes me
want to claw my eyes out. The amount of broken code I just encountered is
mind boggling. I've added comments explaining what is broken, but I fear
that some of the code would be best dealt with by being dragged behind the
bike shed, burying in mud up to it's neck and then run over repeatedly
with a blunt lawn mower.Special mention goes to the zcache/zcache2 drivers. They can't co-exist
in the build at the same time, they are under different menu options in
menuconfig, they only show up when you've got the right set of mm
subsystem options configured and so even compile testing is an exercise in
pulling teeth. And that doesn't even take into account the horrible,
broken code...[glommer@openvz.org: fixes for i915, android lowmem, zcache, bcache]
Signed-off-by: Dave Chinner
Signed-off-by: Glauber Costa
Acked-by: Mel Gorman
Cc: Daniel Vetter
Cc: Kent Overstreet
Cc: John Stultz
Cc: David Rientjes
Cc: Jerome Glisse
Cc: Thomas Hellstrom
Cc: "Theodore Ts'o"
Cc: Adrian Hunter
Cc: Al Viro
Cc: Artem Bityutskiy
Cc: Arve Hjønnevåg
Cc: Carlos Maiolino
Cc: Christoph Hellwig
Cc: Chuck Lever
Cc: Daniel Vetter
Cc: David Rientjes
Cc: Gleb Natapov
Cc: Greg Thelen
Cc: J. Bruce Fields
Cc: Jan Kara
Cc: Jerome Glisse
Cc: John Stultz
Cc: KAMEZAWA Hiroyuki
Cc: Kent Overstreet
Cc: Kirill A. Shutemov
Cc: Marcelo Tosatti
Cc: Mel Gorman
Cc: Steven Whitehouse
Cc: Thomas Hellstrom
Cc: Trond Myklebust
Signed-off-by: Andrew MortonSigned-off-by: Al Viro
11 Jul, 2013
2 commits
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This patch changes dm-bufio so that it submits write I/Os outside of the
lock. If the number of submitted buffers is greater than the number of
requests on the target queue, submit_bio blocks. We want to block outside
of the lock to improve latency of other threads that may need the lock.Signed-off-by: Mikulas Patocka
Signed-off-by: Alasdair G Kergon -
Use __GFP_HIGHMEM in __vmalloc.
Pages allocated with __vmalloc can be allocated in high memory that is not
directly mapped to kernel space, so use __GFP_HIGHMEM just like vmalloc
does. This patch reduces memory pressure slightly because pages can be
allocated in the high zone.Signed-off-by: Mikulas Patocka
Signed-off-by: Alasdair G Kergon
10 May, 2013
1 commit
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This patch uses memalloc_noio_save to avoid a possible deadlock in
dm-bufio. (it could happen only with large block size, at most
PAGE_SIZE << MAX_ORDER (typically 8MiB).__vmalloc doesn't fully respect gfp flags. The specified gfp flags are
used for allocation of requested pages, structures vmap_area, vmap_block
and vm_struct and the radix tree nodes.However, the kernel pagetables are allocated always with GFP_KERNEL.
Thus the allocation of pagetables can recurse back to the I/O layer and
cause a deadlock.This patch uses the function memalloc_noio_save to set per-process
PF_MEMALLOC_NOIO flag and the function memalloc_noio_restore to restore
it. When this flag is set, all allocations in the process are done with
implied GFP_NOIO flag, thus the deadlock can't happen.This should be backported to stable kernels, but they don't have the
PF_MEMALLOC_NOIO flag and memalloc_noio_save/memalloc_noio_restore
functions. So, PF_MEMALLOC should be set and restored instead.Signed-off-by: Mikulas Patocka
Cc: stable@kernel.org
Signed-off-by: Alasdair G Kergon
21 Mar, 2013
1 commit
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A deadlock was found in the prefetch code in the dm verity map
function. This patch fixes this by transferring the prefetch
to a worker thread and skipping it completely if kmalloc fails.If generic_make_request is called recursively, it queues the I/O
request on the current->bio_list without making the I/O request
and returns. The routine making the recursive call cannot wait
for the I/O to complete.The deadlock occurs when one thread grabs the bufio_client
mutex and waits for an I/O to complete but the I/O is queued
on another thread's current->bio_list and is waiting to get
the mutex held by the first thread.The fix recognises that prefetching is not essential. If memory
can be allocated, it queues the prefetch request to the worker thread,
but if not, it does nothing.Signed-off-by: Paul Taysom
Signed-off-by: Mikulas Patocka
Signed-off-by: Alasdair G Kergon
Cc: stable@kernel.org
02 Mar, 2013
1 commit
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Use WRITE_FLUSH instead of REQ_FLUSH for submitted requests to make it
consistent with the rest of the kernel. There is no functional change.Signed-off-by: Mikulas Patocka
Signed-off-by: Alasdair G Kergon
28 Feb, 2013
1 commit
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I'm not sure why, but the hlist for each entry iterators were conceived
list_for_each_entry(pos, head, member)
The hlist ones were greedy and wanted an extra parameter:
hlist_for_each_entry(tpos, pos, head, member)
Why did they need an extra pos parameter? I'm not quite sure. Not only
they don't really need it, it also prevents the iterator from looking
exactly like the list iterator, which is unfortunate.Besides the semantic patch, there was some manual work required:
- Fix up the actual hlist iterators in linux/list.h
- Fix up the declaration of other iterators based on the hlist ones.
- A very small amount of places were using the 'node' parameter, this
was modified to use 'obj->member' instead.
- Coccinelle didn't handle the hlist_for_each_entry_safe iterator
properly, so those had to be fixed up manually.The semantic patch which is mostly the work of Peter Senna Tschudin is here:
@@
iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host;type T;
expression a,c,d,e;
identifier b;
statement S;
@@-T b;
[akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c]
[akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c]
[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: fix warnings]
[akpm@linux-foudnation.org: redo intrusive kvm changes]
Tested-by: Peter Senna Tschudin
Acked-by: Paul E. McKenney
Signed-off-by: Sasha Levin
Cc: Wu Fengguang
Cc: Marcelo Tosatti
Cc: Gleb Natapov
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
12 Oct, 2012
2 commits
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Use the ACCESS_ONCE macro in dm-bufio and dm-verity where a variable
can be modified asynchronously (through sysfs) and we want to prevent
compiler optimizations that assume that the variable hasn't changed.
(See Documentation/atomic_ops.txt.)Signed-off-by: Mikulas Patocka
Signed-off-by: Alasdair G Kergon -
Use list_move() instead of list_del() + list_add().
spatch with a semantic match was used to find this.
(http://coccinelle.lip6.fr/)Signed-off-by: Wei Yongjun
Signed-off-by: Alasdair G Kergon
29 Mar, 2012
1 commit
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This patch introduces a new function dm_bufio_prefetch. It prefetches
the specified range of blocks into dm-bufio cache without waiting
for i/o completion.Signed-off-by: Mikulas Patocka
Signed-off-by: Alasdair G Kergon
04 Feb, 2012
1 commit
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As 'make versioncheck' points out, drivers/md/dm-bufio.c has no need to include
linux/version.h, so this patch removes the unneeded include.Signed-off-by: Jesper Juhl
Acked-by: Mikulas Patocka
Signed-off-by: Jiri Kosina
08 Nov, 2011
1 commit
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since it uses the module facilities.
Reported-by: Witold Baryluk
Signed-off-by: Stephen Rothwell
Signed-off-by: Paul Gortmaker
Signed-off-by: Linus Torvalds
01 Nov, 2011
1 commit
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The dm-bufio interface allows you to do cached I/O on devices,
holding recently-read blocks in memory and performing delayed writes.We don't use buffer cache or page cache already present in the kernel, because:
* we need to handle block sizes larger than a page
* we can't allocate memory to perform reads or we'd have deadlocksCurrently, when a cache is required, we limit its size to a fraction of
available memory. Usage can be viewed and changed in
/sys/module/dm_bufio/parameters/ .The first user is thin provisioning, but more dm users are planned.
Signed-off-by: Mikulas Patocka
Signed-off-by: Alasdair G Kergon