user/sven/linux.git/ipc/mqueue.c, branch v4.7

mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros

2016-04-04T17:41:08Z

PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> ; - >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> ; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov Acked-by: Michal Hocko Signed-off-by: Linus Torvalds

wrappers for ->i_mutex access

2016-01-22T23:04:28Z

parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested}, inode_foo(inode) being mutex_foo(&inode->i_mutex). Please, use those for access to ->i_mutex; over the coming cycle ->i_mutex will become rwsem, with ->lookup() done with it held only shared. Signed-off-by: Al Viro

kmemcg: account certain kmem allocations to memcg

2016-01-15T00:00:49Z

Mark those kmem allocations that are known to be easily triggered from userspace as __GFP_ACCOUNT/SLAB_ACCOUNT, which makes them accounted to memcg. For the list, see below: - threadinfo - task_struct - task_delay_info - pid - cred - mm_struct - vm_area_struct and vm_region (nommu) - anon_vma and anon_vma_chain - signal_struct - sighand_struct - fs_struct - files_struct - fdtable and fdtable->full_fds_bits - dentry and external_name - inode for all filesystems. This is the most tedious part, because most filesystems overwrite the alloc_inode method. The list is far from complete, so feel free to add more objects. Nevertheless, it should be close to "account everything" approach and keep most workloads within bounds. Malevolent users will be able to breach the limit, but this was possible even with the former "account everything" approach (simply because it did not account everything in fact). [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Vladimir Davydov Acked-by: Johannes Weiner Acked-by: Michal Hocko Cc: Tejun Heo Cc: Greg Thelen Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ipc: modify message queue accounting to not take kernel data structures into account

2015-08-07T01:39:39Z

A while back, the message queue implementation in the kernel was improved to use btrees to speed up retrieval of messages, in commit d6629859b36d ("ipc/mqueue: improve performance of send/recv"). That patch introducing the improved kernel handling of message queues (using btrees) has, as a by-product, changed the meaning of the QSIZE field in the pseudo-file created for the queue. Before, this field reflected the size of the user-data in the queue. Since, it also takes kernel data structures into account. For example, if 13 bytes of user data are in the queue, on my machine the file reports a size of 61 bytes. There was some discussion on this topic before (for example https://lkml.org/lkml/2014/10/1/115). Commenting on a th lkml, Michael Kerrisk gave the following background (https://lkml.org/lkml/2015/6/16/74): The pseudofiles in the mqueue filesystem (usually mounted at /dev/mqueue) expose fields with metadata describing a message queue. One of these fields, QSIZE, as originally implemented, showed the total number of bytes of user data in all messages in the message queue, and this feature was documented from the beginning in the mq_overview(7) page. In 3.5, some other (useful) work happened to break the user-space API in a couple of places, including the value exposed via QSIZE, which now includes a measure of kernel overhead bytes for the queue, a figure that renders QSIZE useless for its original purpose, since there's no way to deduce the number of overhead bytes consumed by the implementation. (The other user-space breakage was subsequently fixed.) This patch removes the accounting of kernel data structures in the queue. Reporting the size of these data-structures in the QSIZE field was a breaking change (see Michael's comment above). Without the QSIZE field reporting the total size of user-data in the queue, there is no way to deduce this number. It should be noted that the resource limit RLIMIT_MSGQUEUE is counted against the worst-case size of the queue (in both the old and the new implementation). Therefore, the kernel overhead accounting in QSIZE is not necessary to help the user understand the limitations RLIMIT imposes on the processes. Signed-off-by: Marcus Gelderie Acked-by: Doug Ledford Acked-by: Michael Kerrisk Acked-by: Davidlohr Bueso Cc: David Howells Cc: Alexander Viro Cc: John Duffy Cc: Arto Bendiken Cc: Manfred Spraul Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ipc/mqueue: Implement lockless pipelined wakeups

2015-05-08T10:23:07Z

This patch moves the wakeup_process() invocation so it is not done under the info->lock by making use of a lockless wake_q. With this change, the waiter is woken up once it is STATE_READY and it does not need to loop on SMP if it is still in STATE_PENDING. In the timeout case we still need to grab the info->lock to verify the state. This change should also avoid the introduction of preempt_disable() in -rt which avoids a busy-loop which pools for the STATE_PENDING -> STATE_READY change if the waiter has a higher priority compared to the waker. Additionally, this patch micro-optimizes wq_sleep by using the cheaper cousin of set_current_state(TASK_INTERRUPTABLE) as we will block no matter what, thus get rid of the implied barrier. Signed-off-by: Davidlohr Bueso Signed-off-by: Peter Zijlstra (Intel) Acked-by: George Spelvin Acked-by: Thomas Gleixner Cc: Andrew Morton Cc: Borislav Petkov Cc: Chris Mason Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Manfred Spraul Cc: Peter Zijlstra Cc: Sebastian Andrzej Siewior Cc: Steven Rostedt Cc: dave@stgolabs.net Link: http://lkml.kernel.org/r/1430748166.1940.17.camel@stgolabs.net Signed-off-by: Ingo Molnar

VFS: assorted weird filesystems: d_inode() annotations

2015-04-15T19:06:58Z

Signed-off-by: David Howells Signed-off-by: Al Viro

new helper: audit_file()

2014-11-19T18:01:26Z

... for situations when we don't have any candidate in pathnames - basically, in descriptor-based syscalls. [Folded the build fix for !CONFIG_AUDITSYSCALL configs from Chen Gang] Signed-off-by: Al Viro

ipc: use device_initcall

2014-04-07T23:36:11Z

... since __initcall is now deprecated. Signed-off-by: Davidlohr Bueso Cc: Manfred Spraul Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ipc,mqueue: remove limits for the amount of system-wide queues

2014-02-25T23:25:45Z

Commit 93e6f119c0ce ("ipc/mqueue: cleanup definition names and locations") added global hardcoded limits to the amount of message queues that can be created. While these limits are per-namespace, reality is that it ends up breaking userspace applications. Historically users have, at least in theory, been able to create up to INT_MAX queues, and limiting it to just 1024 is way too low and dramatic for some workloads and use cases. For instance, Madars reports: "This update imposes bad limits on our multi-process application. As our app uses approaches that each process opens its own set of queues (usually something about 3-5 queues per process). In some scenarios we might run up to 3000 processes or more (which of-course for linux is not a problem). Thus we might need up to 9000 queues or more. All processes run under one user." Other affected users can be found in launchpad bug #1155695: https://bugs.launchpad.net/ubuntu/+source/manpages/+bug/1155695 Instead of increasing this limit, revert it entirely and fallback to the original way of dealing queue limits -- where once a user's resource limit is reached, and all memory is used, new queues cannot be created. Signed-off-by: Davidlohr Bueso Reported-by: Madars Vitolins Acked-by: Doug Ledford Cc: Manfred Spraul Cc: [3.5+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ipc: remove braces for single statements

2014-01-28T05:02:39Z

Deal with checkpatch messages: WARNING: braces {} are not necessary for single statement blocks Signed-off-by: Davidlohr Bueso Cc: Aswin Chandramouleeswaran Cc: Rik van Riel Acked-by: Manfred Spraul Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds