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2011-03-24memcg: break out event counters from other statsJohannes Weiner
For increasing and decreasing per-cpu cgroup usage counters it makes sense to use signed types, as single per-cpu values might go negative during updates. But this is not the case for only-ever-increasing event counters. All the counters have been signed 64-bit so far, which was enough to count events even with the sign bit wasted. This patch: - divides s64 counters into signed usage counters and unsigned monotonically increasing event counters. - converts unsigned event counters into 'unsigned long' rather than 'u64'. This matches the type used by the /proc/vmstat event counters. The next patch narrows the signed usage counters type (on 32-bit CPUs, that is). Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Greg Thelen <gthelen@google.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-24memcg: unify charge/uncharge quantities to units of pagesJohannes Weiner
There is no clear pattern when we pass a page count and when we pass a byte count that is a multiple of PAGE_SIZE. We never charge or uncharge subpage quantities, so convert it all to page counts. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-24memcg: convert uncharge batching from bytes to page granularityJohannes Weiner
We never uncharge subpage quantities. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-24memcg: convert per-cpu stock from bytes to page granularityJohannes Weiner
We never keep subpage quantities in the per-cpu stock. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-24memcg: keep only one charge cancelling functionJohannes Weiner
We have two charge cancelling functions: one takes a page count, the other a page size. The second one just divides the parameter by PAGE_SIZE and then calls the first one. This is trivial, no need for an extra function. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-24memcg: remove memcg->reclaim_param_lockJohannes Weiner
The reclaim_param_lock is only taken around single reads and writes to integer variables and is thus superfluous. Drop it. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-24memcg: charged pages always have valid per-memcg zone infoJohannes Weiner
page_cgroup_zoneinfo() will never return NULL for a charged page, remove the check for it in mem_cgroup_get_reclaim_stat_from_page(). Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-24memcg: remove direct page_cgroup-to-page pointerJohannes Weiner
In struct page_cgroup, we have a full word for flags but only a few are reserved. Use the remaining upper bits to encode, depending on configuration, the node or the section, to enable page_cgroup-to-page lookups without a direct pointer. This saves a full word for every page in a system with memory cgroups enabled. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-24memcg: condense page_cgroup-to-page lookup pointsJohannes Weiner
The per-cgroup LRU lists string up 'struct page_cgroup's. To get from those structures to the page they represent, a lookup is required. Currently, the lookup is done through a direct pointer in struct page_cgroup, so a lot of functions down the callchain do this lookup by themselves instead of receiving the page pointer from their callers. The next patch removes this pointer, however, and the lookup is no longer that straight-forward. In preparation for that, this patch only leaves the non-optional lookups when coming directly from the LRU list and passes the page down the stack. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-24memcg: fold __mem_cgroup_move_account into callerJohannes Weiner
It is one logical function, no need to have it split up. Also, get rid of some checks from the inner function that ensured the sanity of the outer function. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-24memcg: change page_cgroup_zoneinfo signatureJohannes Weiner
Instead of passing a whole struct page_cgroup to this function, let it take only what it really needs from it: the struct mem_cgroup and the page. This has the advantage that reading pc->mem_cgroup is now done at the same place where the ordering rules for this pointer are enforced and explained. It is also in preparation for removing the pc->page backpointer. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-24memcg: no uncharged pages reach page_cgroup_zoneinfoJohannes Weiner
This patch series removes the direct page pointer from struct page_cgroup, which saves 20% of per-page memcg memory overhead (Fedora and Ubuntu enable memcg per default, openSUSE apparently too). The node id or section number is encoded in the remaining free bits of pc->flags which allows calculating the corresponding page without the extra pointer. I ran, what I think is, a worst-case microbenchmark that just cats a large sparse file to /dev/null, because it means that walking the LRU list on behalf of per-cgroup reclaim and looking up pages from page_cgroups is happening constantly and at a high rate. But it made no measurable difference. A profile reported a 0.11% share of the new lookup_cgroup_page() function in this benchmark. This patch: All callsites check PCG_USED before passing pc->mem_cgroup, so the latter is never NULL. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-24memcg: add memcg sanity checks at allocating and freeing pagesDaisuke Nishimura
Add checks at allocating or freeing a page whether the page is used (iow, charged) from the view point of memcg. This check may be useful in debugging a problem and we did similar checks before the commit 52d4b9ac(memcg: allocate all page_cgroup at boot). This patch adds some overheads at allocating or freeing memory, so it's enabled only when CONFIG_DEBUG_VM is enabled. Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-24memcg: remove NULL check from lookup_page_cgroup() resultJohannes Weiner
The page_cgroup array is set up before even fork is initialized. I seriously doubt that this code executes before the array is alloc'd. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-24memcg: remove impossible conditional when committingJohannes Weiner
No callsite ever passes a NULL pointer for a struct mem_cgroup * to the committing function. There is no need to check for it. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-24memcg: remove unused page flag bitfield definesJohannes Weiner
These definitions have been unused since '4b3bde4 memcg: remove the overhead associated with the root cgroup'. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-24memcg: simplify the way memory limits are checkedJohannes Weiner
Since transparent huge pages, checking whether memory cgroups are below their limits is no longer enough, but the actual amount of chargeable space is important. To not have more than one limit-checking interface, replace memory_cgroup_check_under_limit() and memory_cgroup_check_margin() with a single memory_cgroup_margin() that returns the chargeable space and leaves the comparison to the callsite. Soft limits are now checked the other way round, by using the already existing function that returns the amount by which soft limits are exceeded: res_counter_soft_limit_excess(). Also remove all the corresponding functions on the res_counter side that are now no longer used. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-24memcg: soft limit reclaim should end at limit not belowJohannes Weiner
Soft limit reclaim continues until the usage is below the current soft limit, but the documented semantics are actually that soft limit reclaim will push usage back until the soft limits are met again. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-24memcg: fix ugly initialization of return value is in callerKAMEZAWA Hiroyuki
Remove initialization of vaiable in caller of memory cgroup function. Actually, it's return value of memcg function but it's initialized in caller. Some memory cgroup uses following style to bring the result of start function to the end function for avoiding races. mem_cgroup_start_A(&(*ptr)) /* Something very complicated can happen here. */ mem_cgroup_end_A(*ptr) In some calls, *ptr should be initialized to NULL be caller. But it's ugly. This patch fixes that *ptr is initialized by _start function. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23mm: implement access_remote_vmStephen Wilson
Provide an alternative to access_process_vm that allows the caller to obtain a reference to the supplied mm_struct. Signed-off-by: Stephen Wilson <wilsons@start.ca> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-23mm: factor out main logic of access_process_vmStephen Wilson
Introduce an internal helper __access_remote_vm and base access_process_vm on top of it. This new method may be called with a NULL task_struct if page fault accounting is not desired. This code will be shared with a new address space accessor that is independent of task_struct. Signed-off-by: Stephen Wilson <wilsons@start.ca> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-23mm: use mm_struct to resolve gate vma's in __get_user_pagesStephen Wilson
We now check if a requested user page overlaps a gate vma using the supplied mm instead of the supplied task. The given task is now used solely for accounting purposes and may be NULL. Signed-off-by: Stephen Wilson <wilsons@start.ca> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-23mm: arch: rename in_gate_area_no_task to in_gate_area_no_mmStephen Wilson
Now that gate vma's are referenced with respect to a particular mm and not a particular task it only makes sense to propagate the change to this predicate as well. Signed-off-by: Stephen Wilson <wilsons@start.ca> Reviewed-by: Michel Lespinasse <walken@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-23mm: arch: make in_gate_area take an mm_struct instead of a task_structStephen Wilson
Morally, the question of whether an address lies in a gate vma should be asked with respect to an mm, not a particular task. Moreover, dropping the dependency on task_struct will help make existing and future operations on mm's more flexible and convenient. Signed-off-by: Stephen Wilson <wilsons@start.ca> Reviewed-by: Michel Lespinasse <walken@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-23mm: arch: make get_gate_vma take an mm_struct instead of a task_structStephen Wilson
Morally, the presence of a gate vma is more an attribute of a particular mm than a particular task. Moreover, dropping the dependency on task_struct will help make both existing and future operations on mm's more flexible and convenient. Signed-off-by: Stephen Wilson <wilsons@start.ca> Reviewed-by: Michel Lespinasse <walken@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-23sys_swapon: fix inode lockingCesar Eduardo Barros
A conflict between 52c50567d8ab ("mm: swap: unlock swapfile inode mutex before closing file on bad swapfiles") and 83ef99befc32 ("sys_swapon: remove did_down variable") caused a double unlock of the inode mutex (once in bad_swap: before the filp_close, once at the end just before returning). The patch which added the extra unlock cleared did_down to avoid unlocking twice, but the other patch removed the did_down variable. To fix, set inode to NULL after the first unlock, since it will be used after that point only for the final unlock. While checking this patch, I found a path which could unlock without locking, in case the same inode was added as a swapfile twice. To fix, move the setting of the inode variable further down, to just before claim_swapfile, which will lock the inode before doing anything else. Cc: Mel Gorman <mgorman@suse.de> Cc: Hugh Dickins <hughd@google.com> Cc: Eric B Munson <emunson@mgebm.net> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23mm: simplify code of swap.cShaohua Li
Clean up code and remove duplicate code. Next patch will use pagevec_lru_move_fn introduced here too. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Hiroyuki Kamezawa <kamezawa.hiroyuki@gmail.com> Cc: Andi Kleen <andi@firstfloor.org> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23shmem: let shared anonymous be nonlinear againHugh Dickins
Up to 2.6.22, you could use remap_file_pages(2) on a tmpfs file or a shared mapping of /dev/zero or a shared anonymous mapping. In 2.6.23 we disabled it by default, but set VM_CAN_NONLINEAR to enable it on safe mappings. We made sure to set it in shmem_mmap() for tmpfs files, but missed it in shmem_zero_setup() for the others. Fix that at last. Reported-by: Kenny Simpson <theonetruekenny@yahoo.com> Signed-off-by: Hugh Dickins <hughd@google.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23mm/memblock: properly handle overlaps and fix error pathBenjamin Herrenschmidt
Currently memblock_reserve() or memblock_free() don't handle overlaps of any kind. There is some special casing for coalescing exactly adjacent regions but that's about it. This is annoying because typically memblock_reserve() is used to mark regions passed by the firmware as reserved and we all know how much we can trust our firmwares... Also, with the current code, if we do something it doesn't handle right such as trying to memblock_reserve() a large range spanning multiple existing smaller reserved regions for example, or doing overlapping reservations, it can silently corrupt the internal region array, causing odd errors much later on, such as allocations returning reserved regions etc... This patch rewrites the underlying functions that add or remove a region to the arrays. The new code is a lot more robust as it fully handles overlapping regions. It's also, imho, simpler than the previous implementation. In addition, while doing so, I found a bug where if we fail to double the array while adding a region, we would remove the last region of the array rather than the region we just allocated. This fixes it too. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Yinghai Lu <yinghai@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23mm/page_alloc.c: use list_move() instead of list_del()/list_add() combinationKirill A. Shutemov
Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Rik van Riel <riel@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23vmalloc: remove confusing comment on vwrite()Namhyung Kim
KM_USER1 is never used for vwrite() path so the caller doesn't need to guarantee it is not used. Only the caller should guarantee is KM_USER0 and it is commented already. Signed-off-by: Namhyung Kim <namhyung@gmail.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23writeback: make mapping->writeback_index to point to the last written pageJun'ichi Nomura
For range-cyclic writeback (e.g. kupdate), the writeback code sets a continuation point of the next writeback to mapping->writeback_index which is set the page after the last written page. This happens so that we evenly write the whole file even if pages in it get continuously redirtied. However, in some cases, sequential writer is writing in the middle of the page and it just redirties the last written page by continuing from that. For example with an application which uses a file as a big ring buffer we see: [1st writeback session] ... flush-8:0-2743 4571: block_bio_queue: 8,0 W 94898514 + 8 flush-8:0-2743 4571: block_bio_queue: 8,0 W 94898522 + 8 flush-8:0-2743 4571: block_bio_queue: 8,0 W 94898530 + 8 flush-8:0-2743 4571: block_bio_queue: 8,0 W 94898538 + 8 flush-8:0-2743 4571: block_bio_queue: 8,0 W 94898546 + 8 kworker/0:1-11 4571: block_rq_issue: 8,0 W 0 () 94898514 + 40 >> flush-8:0-2743 4571: block_bio_queue: 8,0 W 94898554 + 8 >> flush-8:0-2743 4571: block_rq_issue: 8,0 W 0 () 94898554 + 8 [2nd writeback session after 35sec] flush-8:0-2743 4606: block_bio_queue: 8,0 W 94898562 + 8 flush-8:0-2743 4606: block_bio_queue: 8,0 W 94898570 + 8 flush-8:0-2743 4606: block_bio_queue: 8,0 W 94898578 + 8 ... kworker/0:1-11 4606: block_rq_issue: 8,0 W 0 () 94898562 + 640 kworker/0:1-11 4606: block_rq_issue: 8,0 W 0 () 94899202 + 72 ... flush-8:0-2743 4606: block_bio_queue: 8,0 W 94899962 + 8 flush-8:0-2743 4606: block_bio_queue: 8,0 W 94899970 + 8 flush-8:0-2743 4606: block_bio_queue: 8,0 W 94899978 + 8 flush-8:0-2743 4606: block_bio_queue: 8,0 W 94899986 + 8 flush-8:0-2743 4606: block_bio_queue: 8,0 W 94899994 + 8 kworker/0:1-11 4606: block_rq_issue: 8,0 W 0 () 94899962 + 40 >> flush-8:0-2743 4606: block_bio_queue: 8,0 W 94898554 + 8 >> flush-8:0-2743 4606: block_rq_issue: 8,0 W 0 () 94898554 + 8 So we seeked back to 94898554 after we wrote all the pages at the end of the file. This extra seek seems unnecessary. If we continue writeback from the last written page, we can avoid it and do not cause harm to other cases. The original intent of even writeout over the whole file is preserved and if the page does not get redirtied pagevec_lookup_tag() just skips it. As an exceptional case, when I/O error happens, set done_index to the next page as the comment in the code suggests. Tested-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23mm: remove inline from scan_swap_map()Cesar Eduardo Barros
scan_swap_map() is a large function (224 lines), with several loops and a complex control flow involving several gotos. Given all that, it is a bit silly that it is marked as inline. The compiler agrees with me: on a x86-64 compile, it did not inline the function. Remove the "inline" and let the compiler decide instead. Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net> Reviewed-by: Pekka Enberg <penberg@kernel.org> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23sys_swapon: separate final enabling of the swapfileCesar Eduardo Barros
The block in sys_swapon which does the final adjustments to the swap_info_struct and to swap_list is the same as the block which re-inserts it again at sys_swapoff on failure of try_to_unuse(). Move this code to a separate function, and use it both in sys_swapon and sys_swapoff. Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net> Tested-by: Eric B Munson <emunson@mgebm.net> Acked-by: Eric B Munson <emunson@mgebm.net> Reviewed-by: Pekka Enberg <penberg@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23sys_swapoff: change order to match sys_swaponCesar Eduardo Barros
The block in sys_swapon which does the final adjustments to the swap_info_struct and to swap_list is the same as the block which re-inserts it again at sys_swapoff on failure of try_to_unuse(), except for the order of the operations within the lock. Since the order should not matter, arbitrarily change sys_swapoff to match sys_swapon, in preparation to making both share the same code. Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net> Tested-by: Eric B Munson <emunson@mgebm.net> Acked-by: Eric B Munson <emunson@mgebm.net> Reviewed-by: Pekka Enberg <penberg@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23sys_swapon: move printk outside lockCesar Eduardo Barros
The block in sys_swapon which does the final adjustments to the swap_info_struct and to swap_list is the same as the block which re-inserts it again at sys_swapoff on failure of try_to_unuse(). To be able to make both share the same code, move the printk() call in the middle of it to just after it. Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net> Tested-by: Eric B Munson <emunson@mgebm.net> Acked-by: Eric B Munson <emunson@mgebm.net> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23sys_swapon: remove nr_good_pages variableCesar Eduardo Barros
It still exists within setup_swap_map_and_extents(), but after it nr_good_pages == p->pages. Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net> Tested-by: Eric B Munson <emunson@mgebm.net> Acked-by: Eric B Munson <emunson@mgebm.net> Reviewed-by: Pekka Enberg <penberg@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23sys_swapon: simplify error flow in setup_swap_map_and_extents()Cesar Eduardo Barros
Since there is no cleanup to do, there is no reason to jump to a label. Return directly instead. Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net> Tested-by: Eric B Munson <emunson@mgebm.net> Acked-by: Eric B Munson <emunson@mgebm.net> Reviewed-by: Pekka Enberg <penberg@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23sys_swapon: separate parsing of bad blocks and extentsCesar Eduardo Barros
Move the code which parses the bad block list and the extents to a separate function. Only code movement, no functional changes. This change uses the fact that, after the success path, nr_good_pages == p->pages. Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net> Tested-by: Eric B Munson <emunson@mgebm.net> Acked-by: Eric B Munson <emunson@mgebm.net> Reviewed-by: Pekka Enberg <penberg@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23sys_swapon: call swap_cgroup_swapon() earlierCesar Eduardo Barros
The call to swap_cgroup_swapon is in the middle of loading the swap map and extents. As it only does memory allocation and does not depend on the swapfile layout (map/extents), it can be called earlier (or later). Move it to just after the allocation of swap_map, since it is conceptually similar (allocates a map). Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net> Tested-by: Eric B Munson <emunson@mgebm.net> Acked-by: Eric B Munson <emunson@mgebm.net> Reviewed-by: Pekka Enberg <penberg@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23sys_swapon: simplify error flow in read_swap_header()Cesar Eduardo Barros
Since there is no cleanup to do, there is no reason to jump to a label. Return directly instead. Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net> Tested-by: Eric B Munson <emunson@mgebm.net> Acked-by: Eric B Munson <emunson@mgebm.net> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23sys_swapon: separate parsing of swapfile headerCesar Eduardo Barros
Move the code which parses and checks the swapfile header (except for the bad block list) to a separate function. Only code movement, no functional changes. Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net> Tested-by: Eric B Munson <emunson@mgebm.net> Acked-by: Eric B Munson <emunson@mgebm.net> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23sys_swapon: move setting of swapfilepages near useCesar Eduardo Barros
There is no reason I can see to read inode->i_size long before it is needed. Move its read to just before it is needed, to reduce the variable lifetime. Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net> Tested-by: Eric B Munson <emunson@mgebm.net> Acked-by: Eric B Munson <emunson@mgebm.net> Reviewed-by: Jesper Juhl <jj@chaosbits.net> Reviewed-by: Pekka Enberg <penberg@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23sys_swapon: simplify error flow in claim_swapfile()Cesar Eduardo Barros
Since there is no cleanup to do, there is no reason to jump to a label. Return directly instead. Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net> Tested-by: Eric B Munson <emunson@mgebm.net> Acked-by: Eric B Munson <emunson@mgebm.net> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23sys_swapon: separate bdev claim and inode lockCesar Eduardo Barros
Move the code which claims the bdev (S_ISBLK) or locks the inode (S_ISREG) to a separate function. Only code movement, no functional changes. Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net> Tested-by: Eric B Munson <emunson@mgebm.net> Acked-by: Eric B Munson <emunson@mgebm.net> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23sys_swapon: use a single error labelCesar Eduardo Barros
sys_swapon currently has two error labels, bad_swap and bad_swap_2. bad_swap does the same as bad_swap_2 plus destroy_swap_extents() and swap_cgroup_swapoff(); both are noops in the places where bad_swap_2 is jumped to. With a single extra test for inode (matching the one in the S_ISREG case below), all the error paths in the function can go to bad_swap. Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net> Tested-by: Eric B Munson <emunson@mgebm.net> Acked-by: Eric B Munson <emunson@mgebm.net> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23sys_swapon: do only cleanup in the cleanup blocksCesar Eduardo Barros
The only way error is 0 in the cleanup blocks is when the function is returning successfully. In this case, the cleanup blocks were setting S_SWAPFILE in the S_ISREG case. But this is not a cleanup. Move the setting of S_SWAPFILE to just before the "goto out;" to make this more clear. At this point, we do not need to test for inode because it will never be NULL. Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net> Tested-by: Eric B Munson <emunson@mgebm.net> Acked-by: Eric B Munson <emunson@mgebm.net> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23sys_swapon: remove bdev variableCesar Eduardo Barros
The bdev variable is always equivalent to (S_ISBLK(inode->i_mode) ? p->bdev : NULL), as long as it being set is moved to a bit earlier. Use this fact to remove the bdev variable. Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net> Tested-by: Eric B Munson <emunson@mgebm.net> Acked-by: Eric B Munson <emunson@mgebm.net> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23sys_swapon: move setting of error nearer useCesar Eduardo Barros
Move the setting of the error variable nearer the goto in a few places. Avoids calling PTR_ERR() if not IS_ERR() in two places, and makes the error condition more explicit in two other places. Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net> Tested-by: Eric B Munson <emunson@mgebm.net> Acked-by: Eric B Munson <emunson@mgebm.net> Reviewed-by: Jesper Juhl <jj@chaosbits.net> Reviewed-by: Pekka Enberg <penberg@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-23sys_swapon: remove did_down variableCesar Eduardo Barros
Since mutex_lock(&inode->i_mutex) is called just after setting inode, did_down is always equivalent to (inode && S_ISREG(inode->i_mode)). Use this fact to remove the did_down variable. Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net> Tested-by: Eric B Munson <emunson@mgebm.net> Acked-by: Eric B Munson <emunson@mgebm.net> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>