- 26 Jul, 2011 40 commits
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Richard Weinberger authored
Until now UML had no x86_64 vDSO. So glibc always used the vsyscall page for gettimeday() and friends. Calls to gettimeday() returned falsely the host time and confused some programs. This patch adds a vDSO which turns all __vdso_* calls into a system call so that UML can trap them. As glibc still uses the vsyscall page for static binaries this patch improves the situation only for dynamic binaries. Signed-off-by:
Richard Weinberger <richard@nod.at> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Richard Weinberger authored
Implement arch_vma_name() and make get_gate_vma(), in_gate_area() and in_gate_area_no_mm() a nop. We need arch_vma_name() to support vDSO. Signed-off-by:
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Richard Weinberger authored
When UML is unable to reuse the host's vDSO FIXADDR_USER_START is zero. To handle this special case correclty we have to implement custom gate area helper methods. Signed-off-by:
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Richard Weinberger authored
Reusing the host's vDSO makes only sense on x86_32. Signed-off-by:
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Davidlohr Bueso authored
When creating the temp file there's a memory and file descriptor leak upon error. Signed-off-by:
Davidlohr Bueso <dave@gnu.org> Signed-off-by:
Vitaliy Ivanov <vitalivanov@gmail.com> Signed-off-by:
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Vitaliy Ivanov authored
Do not free memory when you failed to allocate it. Signed-off-by:
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Vitaliy Ivanov authored
Fix this warning: arch/um/os-Linux/helper.c: In function `helper_child': arch/um/os-Linux/helper.c:38:7: warning: ignoring return value of `write', declared with attribute warn_unused_result [richard@nod.at: happens only with -D_FORTIFY_SOURCE=2] Signed-off-by:
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Vitaliy Ivanov authored
Fix this warning: arch/um/drivers/cow_user.c: In function `absolutize': arch/um/drivers/cow_user.c:189:7: warning: ignoring return value of `chdir', declared with attribute warn_unused_result [richard@nod.at: happens only with -D_FORTIFY_SOURCE=2] Signed-off-by:
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Vitaliy Ivanov authored
Perform memory cleanup on exit. On receiving invalid 'pid' we still should clean 'output' variable. Signed-off-by:
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Geert Uytterhoeven authored
Commit 0954828f ("kconfig: replace KERNELVERSION usage by the mainmenu's prompt") made the kernel version disappear from the generated .config file when configuring for UML. As UML's Kconfig doesn't have a mainmenu, kconfig falls back to the default string "Linux Kernel Configuration". Add a suitable mainmenu to the main UML Kconfig file to fix this. Signed-off-by:
Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by:
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Richard Weinberger authored
To make netconsole usable on UML, its ethernet driver needs netpoll support. Signed-off-by:
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Richard Weinberger authored
When UML is compiled with _FORTIFY_SOURCE we have to export all _chk() functions which are used in modules. For now it's only the case for __sprintf_chk(). Tested-by:
Florian Fainelli <florian@openwrt.org> Reported-by:
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Richard Weinberger authored
Both sys-i386 and sys-x86_64 support now ndelay(). The delay functions are based on arch/x86/lib/delay.c. Signed-off-by:
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Mathias Krause authored
The address limit is already set in flush_old_exec() so this set_fs(USER_DS) is redundant. Signed-off-by:
Mathias Krause <minipli@googlemail.com> Cc: Richard Weinberger <richard@nod.at> Signed-off-by:
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Richard Weinberger authored
There is no need to define VM_{STACK,DATA}_DEFAULT_FLAGS as variable. It's also useless to test for TIF_IA32 as 64bit UML has no IA32 emulation. Signed-off-by:Randy Dunlap <rdunlap@xenotime.net> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by:
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Mathias Krause authored
The address limit is already set in flush_old_exec() so those calls to set_fs(USER_DS) are redundant. Signed-off-by:
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WANG Cong authored
Fix some harmless warnings such as arch/cris/arch-v32/mach-a3/pinmux.c:273: warning: ISO C90 forbids mixed declarations and code: Signed-off-by:
WANG Cong <xiyou.wangcong@gmail.com> Cc: Mikael Starvik <starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Signed-off-by:
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Mathias Krause authored
The address limit is already set in flush_old_exec() so those calls to set_fs(USER_DS) are redundant. Signed-off-by:
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Mathias Krause authored
The address limit is already set in flush_old_exec() so this set_fs(USER_DS) is redundant. Signed-off-by:
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Mathias Krause authored
The address limit is already set in flush_old_exec() so this set_fs(USER_DS) is redundant. Signed-off-by:
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Mathias Krause authored
The address limit is already set in flush_old_exec() so those calls to set_fs(USER_DS) are redundant. Signed-off-by:
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Wu Fengguang authored
NR_WRITTEN is now accounted at block IO enqueue time, which is not very accurate as to common understanding. This moves NR_WRITTEN accounting to the IO completion time and makes it more consistent with BDI_WRITTEN, which is used for bandwidth estimation. Signed-off-by:
Wu Fengguang <fengguang.wu@intel.com> Cc: Michael Rubin <mrubin@google.com> Signed-off-by:
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Hugh Dickins authored
shmem_unuse_inode() and shmem_writepage() contain a little code to cope with pages inserted independently into the filecache, probably by a filesystem stacked on top of tmpfs, then fed to its ->readpage() or ->writepage(). Unionfs was indeed experimenting with working in that way three years ago, but I find no current examples: nowadays the stacking filesystems use vfs interfaces to the lower filesystem. It's now illegal: remove most of that code, adding some WARN_ON_ONCEs. Signed-off-by:
Hugh Dickins <hughd@google.com> Cc: Erez Zadok <ezk@fsl.cs.sunysb.edu> Signed-off-by:
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Hugh Dickins authored
We can now simplify shmem_getpage_gfp(): there is no longer a dilemma of filepage passed in via shmem_readpage(), then swappage found, which must then be copied over to it. Although at first it's tempting to replace the **pagep arg by returning struct page *, that makes a mess of IS_ERR_OR_NULL(page)s in all the callers, so leave as is. Insert BUG_ON(!PageUptodate) when we find and lock page: some of the complication came from uninitialized pages inserted into filecache prior to readpage; but now we're in control, and only release pagelock on filecache once it's uptodate (if an error occurs in reading back from swap, the page remains in swapcache, never moved to filecache). Signed-off-by:
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Hugh Dickins authored
The prealloc_page handling in shmem_getpage_gfp() is unnecessarily complicated: first simplify that before going on to filepage/swappage. That's right, don't report ENOMEM when the preallocation fails: we may or may not need the page. But simply report ENOMEM once we find we do need it, instead of dropping lock, repeating allocation, unwinding on failure etc. And leave the out label on the fast path, don't goto. Fix something that looks like a bug but turns out not to be: set PageSwapBacked on prealloc_page before its mem_cgroup_cache_charge(), as the removed case was doing. That's important before adding to LRU (determines which LRU the page goes on), and does affect which path it takes through memcontrol.c, but in the end MEM_CGROUP_CHANGE_TYPE_ SHMEM is handled no differently from CACHE. Signed-off-by:
Shaohua Li <shaohua.li@intel.com> Cc: "Zhang, Yanmin" <yanmin.zhang@intel.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Signed-off-by:
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Hugh Dickins authored
Remove that pernicious shmem_readpage() at last: the things we needed it for (splice, loop, sendfile, i915 GEM) are now fully taken care of by shmem_file_splice_read() and shmem_read_mapping_page_gfp(). This removal clears the way for a simpler shmem_getpage_gfp(), since page is never passed in; but leave most of that cleanup until after. sys_readahead() and sys_fadvise(POSIX_FADV_WILLNEED) will now EINVAL, instead of unexpectedly trying to read ahead on tmpfs: if that proves to be an issue for someone, then we can either arrange for them to return success instead, or try to implement async readahead on tmpfs. Signed-off-by:
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Hugh Dickins authored
Make shmem_getpage() a wrapper, passing mapping_gfp_mask() down to shmem_getpage_gfp(), which in turn passes gfp down to shmem_swp_alloc(). Change shmem_read_mapping_page_gfp() to use shmem_getpage_gfp() in the CONFIG_SHMEM case; but leave tiny !SHMEM using read_cache_page_gfp(). Add a BUG_ON() in case anyone happens to call this on a non-shmem mapping; though we might later want to let that case route to read_cache_page_gfp(). It annoys me to have these two almost-redundant args, gfp and fault_type: I can't find a better way; but initialize fault_type only in shmem_fault(). Note that before, read_cache_page_gfp() was allocating i915_gem's pages with __GFP_NORETRY as intended; but the corresponding swap vector pages got allocated without it, leaving a small possibility of OOM. Signed-off-by:
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Hugh Dickins authored
Tidy up shmem_file_splice_read(): Remove readahead: okay, we could implement shmem readahead on swap, but have never done so before, swap being the slow exceptional path. Use shmem_getpage() instead of find_or_create_page() plus ->readpage(). Remove several comments: sorry, I found them more distracting than helpful, and this will not be the reference version of splice_read(). Signed-off-by:
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Hugh Dickins authored
Copy __generic_file_splice_read() and generic_file_splice_read() from fs/splice.c to shmem_file_splice_read() in mm/shmem.c. Make page_cache_pipe_buf_ops and spd_release_page() accessible to it. Signed-off-by:
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Benjamin Herrenschmidt authored
I haven't reproduced it myself but the fail scenario is that on such machines (notably ARM and some embedded powerpc), if you manage to hit that futex path on a writable page whose dirty bit has gone from the PTE, you'll livelock inside the kernel from what I can tell. It will go in a loop of trying the atomic access, failing, trying gup to "fix it up", getting succcess from gup, go back to the atomic access, failing again because dirty wasn't fixed etc... So I think you essentially hang in the kernel. The scenario is probably rare'ish because affected architecture are embedded and tend to not swap much (if at all) so we probably rarely hit the case where dirty is missing or young is missing, but I think Shan has a piece of SW that can reliably reproduce it using a shared writable mapping & fork or something like that. On archs who use SW tracking of dirty & young, a page without dirty is effectively mapped read-only and a page without young unaccessible in the PTE. Additionally, some architectures might lazily flush the TLB when relaxing write protection (by doing only a local flush), and expect a fault to invalidate the stale entry if it's still present on another processor. The futex code assumes that if the "in_atomic()" access -EFAULT's, it can "fix it up" by causing get_user_pages() which would then be equivalent to taking the fault. However that isn't the case. get_user_pages() will not call handle_mm_fault() in the case where the PTE seems to have the right permissions, regardless of the dirty and young state. It will eventually update those bits ... in the struct page, but not in the PTE. Additionally, it will not handle the lazy TLB flushing that can be required by some architectures in the fault case. Basically, gup is the wrong interface for the job. The patch provides a more appropriate one which boils down to just calling handle_mm_fault() since what we are trying to do is simulate a real page fault. The futex code currently attempts to write to user memory within a pagefault disabled section, and if that fails, tries to fix it up using get_user_pages(). This doesn't work on archs where the dirty and young bits are maintained by software, since they will gate access permission in the TLB, and will not be updated by gup(). In addition, there's an expectation on some archs that a spurious write fault triggers a local TLB flush, and that is missing from the picture as well. I decided that adding those "features" to gup() would be too much for this already too complex function, and instead added a new simpler fixup_user_fault() which is essentially a wrapper around handle_mm_fault() which the futex code can call. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix some nits Darren saw, fiddle comment layout] Signed-off-by:
Benjamin Herrenschmidt <benh@kernel.crashing.org> Reported-by:
Shan Hai <haishan.bai@gmail.com> Tested-by:
Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Darren Hart <darren.hart@intel.com> Cc: <stable@kernel.org> Signed-off-by:
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Konstantin Khlebnikov authored
radix_tree_tagged() is lockless - it reads from a member of the raid-tree root node. It does not require any protection. Signed-off-by:
Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Hugh Dickins <hughd@google.com> Signed-off-by:
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Mel Gorman authored
With zone_reclaim_mode enabled, it's possible for zones to be considered full in the zonelist_cache so they are skipped in the future. If the process enters direct reclaim, the ZLC may still consider zones to be full even after reclaiming pages. Reconsider all zones for allocation if direct reclaim returns successfully. Signed-off-by:
Mel Gorman <mgorman@suse.de> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Christoph Lameter <cl@linux.com> Signed-off-by:
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Mel Gorman authored
There have been a small number of complaints about significant stalls while copying large amounts of data on NUMA machines reported on a distribution bugzilla. In these cases, zone_reclaim was enabled by default due to large NUMA distances. In general, the complaints have not been about the workload itself unless it was a file server (in which case the recommendation was disable zone_reclaim). The stalls are mostly due to significant amounts of time spent scanning the preferred zone for pages to free. After a failure, it might fallback to another node (as zonelists are often node-ordered rather than zone-ordered) but stall quickly again when the next allocation attempt occurs. In bad cases, each page allocated results in a full scan of the preferred zone. Patch 1 checks the preferred zone for recent allocation failure which is particularly important if zone_reclaim has failed recently. This avoids rescanning the zone in the near future and instead falling back to another node. This may hurt node locality in some cases but a failure to zone_reclaim is more expensive than a remote access. Patch 2 clears the zlc information after direct reclaim. Otherwise, zone_reclaim can mark zones full, direct reclaim can reclaim enough pages but the zone is still not considered for allocation. This was tested on a 24-thread 2-node x86_64 machine. The tests were focused on large amounts of IO. All tests were bound to the CPUs on node-0 to avoid disturbances due to processes being scheduled on different nodes. The kernels tested are 3.0-rc6-vanilla Vanilla 3.0-rc6 zlcfirst Patch 1 applied zlcreconsider Patches 1+2 applied FS-Mark ./fs_mark -d /tmp/fsmark-10813 -D 100 -N 5000 -n 208 -L 35 -t 24 -S0 -s 524288 fsmark-3.0-rc6 3.0-rc6 3.0-rc6 vanilla zlcfirs zlcreconsider Files/s min 54.90 ( 0.00%) 49.80 (-10.24%) 49.10 (-11.81%) Files/s mean 100.11 ( 0.00%) 135.17 (25.94%) 146.93 (31.87%) Files/s stddev 57.51 ( 0.00%) 138.97 (58.62%) 158.69 (63.76%) Files/s max 361.10 ( 0.00%) 834.40 (56.72%) 802.40 (55.00%) Overhead min 76704.00 ( 0.00%) 76501.00 ( 0.27%) 77784.00 (-1.39%) Overhead mean 1485356.51 ( 0.00%) 1035797.83 (43.40%) 1594680.26 (-6.86%) Overhead stddev 1848122.53 ( 0.00%) 881489.88 (109.66%) 1772354.90 ( 4.27%) Overhead max 7989060.00 ( 0.00%) 3369118.00 (137.13%) 10135324.00 (-21.18%) MMTests Statistics: duration User/Sys Time Running Test (seconds) 501.49 493.91 499.93 Total Elapsed Time (seconds) 2451.57 2257.48 2215.92 MMTests Statistics: vmstat Page Ins 46268 63840 66008 Page Outs 90821596 90671128 88043732 Swap Ins 0 0 0 Swap Outs 0 0 0 Direct pages scanned 13091697 8966863 8971790 Kswapd pages scanned 0 1830011 1831116 Kswapd pages reclaimed 0 1829068 1829930 Direct pages reclaimed 13037777 8956828 8648314 Kswapd efficiency 100% 99% 99% Kswapd velocity 0.000 810.643 826.346 Direct efficiency 99% 99% 96% Direct velocity 5340.128 3972.068 4048.788 Percentage direct scans 100% 83% 83% Page writes by reclaim 0 3 0 Slabs scanned 796672 720640 720256 Direct inode steals 7422667 7160012 7088638 Kswapd inode steals 0 1736840 2021238 Test completes far faster with a large increase in the number of files created per second. Standard deviation is high as a small number of iterations were much higher than the mean. The number of pages scanned by zone_reclaim is reduced and kswapd is used for more work. LARGE DD 3.0-rc6 3.0-rc6 3.0-rc6 vanilla zlcfirst zlcreconsider download tar 59 ( 0.00%) 59 ( 0.00%) 55 ( 7.27%) dd source files 527 ( 0.00%) 296 (78.04%) 320 (64.69%) delete source 36 ( 0.00%) 19 (89.47%) 20 (80.00%) MMTests Statistics: duration User/Sys Time Running Test (seconds) 125.03 118.98 122.01 Total Elapsed Time (seconds) 624.56 375.02 398.06 MMTests Statistics: vmstat Page Ins 3594216 439368 407032 Page Outs 23380832 23380488 23377444 Swap Ins 0 0 0 Swap Outs 0 436 287 Direct pages scanned 17482342 69315973 82864918 Kswapd pages scanned 0 519123 575425 Kswapd pages reclaimed 0 466501 522487 Direct pages reclaimed 5858054 2732949 2712547 Kswapd efficiency 100% 89% 90% Kswapd velocity 0.000 1384.254 1445.574 Direct efficiency 33% 3% 3% Direct velocity 27991.453 184832.737 208171.929 Percentage direct scans 100% 99% 99% Page writes by reclaim 0 5082 13917 Slabs scanned 17280 29952 35328 Direct inode steals 115257 1431122 332201 Kswapd inode steals 0 0 979532 This test downloads a large tarfile and copies it with dd a number of times - similar to the most recent bug report I've dealt with. Time to completion is reduced. The number of pages scanned directly is still disturbingly high with a low efficiency but this is likely due to the number of dirty pages encountered. The figures could probably be improved with more work around how kswapd is used and how dirty pages are handled but that is separate work and this result is significant on its own. Streaming Mapped Writer MMTests Statistics: duration User/Sys Time Running Test (seconds) 124.47 111.67 112.64 Total Elapsed Time (seconds) 2138.14 1816.30 1867.56 MMTests Statistics: vmstat Page Ins 90760 89124 89516 Page Outs 121028340 120199524 120736696 Swap Ins 0 86 55 Swap Outs 0 0 0 Direct pages scanned 114989363 96461439 96330619 Kswapd pages scanned 56430948 56965763 57075875 Kswapd pages reclaimed 27743219 27752044 27766606 Direct pages reclaimed 49777 46884 36655 Kswapd efficiency 49% 48% 48% Kswapd velocity 26392.541 31363.631 30561.736 Direct efficiency 0% 0% 0% Direct velocity 53780.091 53108.759 51581.004 Percentage direct scans 67% 62% 62% Page writes by reclaim 385 122 1513 Slabs scanned 43008 39040 42112 Direct inode steals 0 10 8 Kswapd inode steals 733 534 477 This test just creates a large file mapping and writes to it linearly. Time to completion is again reduced. The gains are mostly down to two things. In many cases, there is less scanning as zone_reclaim simply gives up faster due to recent failures. The second reason is that memory is used more efficiently. Instead of scanning the preferred zone every time, the allocator falls back to another zone and uses it instead improving overall memory utilisation. This patch: initialise ZLC for first zone eligible for zone_reclaim. The zonelist cache (ZLC) is used among other things to record if zone_reclaim() failed for a particular zone recently. The intention is to avoid a high cost scanning extremely long zonelists or scanning within the zone uselessly. Currently the zonelist cache is setup only after the first zone has been considered and zone_reclaim() has been called. The objective was to avoid a costly setup but zone_reclaim is itself quite expensive. If it is failing regularly such as the first eligible zone having mostly mapped pages, the cost in scanning and allocation stalls is far higher than the ZLC initialisation step. This patch initialises ZLC before the first eligible zone calls zone_reclaim(). Once initialised, it is checked whether the zone failed zone_reclaim recently. If it has, the zone is skipped. As the first zone is now being checked, additional care has to be taken about zones marked full. A zone can be marked "full" because it should not have enough unmapped pages for zone_reclaim but this is excessive as direct reclaim or kswapd may succeed where zone_reclaim fails. Only mark zones "full" after zone_reclaim fails if it failed to reclaim enough pages after scanning. Signed-off-by: -
KAMEZAWA Hiroyuki authored
Currently we are keeping faulted page locked throughout whole __do_fault call (except for page_mkwrite code path) after calling file system's fault code. If we do early COW, we allocate a new page which has to be charged for a memcg (mem_cgroup_newpage_charge). This function, however, might block for unbounded amount of time if memcg oom killer is disabled or fork-bomb is running because the only way out of the OOM situation is either an external event or OOM-situation fix. In the end we are keeping the faulted page locked and blocking other processes from faulting it in which is not good at all because we are basically punishing potentially an unrelated process for OOM condition in a different group (I have seen stuck system because of ld-2.11.1.so being locked). We can do test easily. % cgcreate -g memory:A % cgset -r memory.limit_in_bytes=64M A % cgset -r memory.memsw.limit_in_bytes=64M A % cd kernel_dir; cgexec -g memory:A make -j Then, the whole system will live-locked until you kill 'make -j' by hands (or push reboot...) This is because some important page in a a shared library are locked. Considering again, the new page is not necessary to be allocated with lock_page() held. And usual page allocation may dive into long memory reclaim loop with holding lock_page() and can cause very long latency. There are 3 ways. 1. do allocation/charge before lock_page() Pros. - simple and can handle page allocation in the same manner. This will reduce holding time of lock_page() in general. Cons. - we do page allocation even if ->fault() returns error. 2. do charge after unlock_page(). Even if charge fails, it's just OOM. Pros. - no impact to non-memcg path. Cons. - implemenation requires special cares of LRU and we need to modify page_add_new_anon_rmap()... 3. do unlock->charge->lock again method. Pros. - no impact to non-memcg path. Cons. - This may kill LOCK_PAGE_RETRY optimization. We need to release lock and get it again... This patch moves "charge" and memory allocation for COW page before lock_page(). Then, we can avoid scanning LRU with holding a lock on a page and latency under lock_page() will be reduced. Then, above livelock disappears. [akpm@linux-foundation.org: fix code layout] Signed-off-by:KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reported-by:
Lutz Vieweg <lvml@5t9.de> Original-idea-by:
Michal Hocko <mhocko@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Ying Han <yinghan@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by:
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Hugh Dickins authored
2.6.36's 7e496299 ("tmpfs: make tmpfs scalable with percpu_counter for used blocks") to make tmpfs scalable with percpu_counter used inode->i_lock in place of sbinfo->stat_lock around i_blocks updates; but that was adverse to scalability, and unnecessary, since info->lock is already held there in the fast paths. Remove those uses of i_lock, and add info->lock in the three error paths where it's then needed across shmem_free_blocks(). It's not actually needed across shmem_unacct_blocks(), but they're so often paired that it looks wrong to split them apart. Signed-off-by:
Tim Chen <tim.c.chen@linux.intel.com> Signed-off-by:
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Hugh Dickins authored
truncate_inode_pages_range()'s final loop has a nice pincer property, bringing start and end together, squeezing out the last pages. But the range handling missed out on that, just sliding up the range, perhaps letting pages come in behind it. Add one more test to give it the same pincer effect. Signed-off-by:
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Hugh Dickins authored
Make the pagevec_lookup loops in truncate_inode_pages_range(), invalidate_mapping_pages() and invalidate_inode_pages2_range() more consistent with each other. They were relying upon page->index of an unlocked page, but apologizing for it: accept it, embrace it, add comments and WARN_ONs, and simplify the index handling. invalidate_inode_pages2_range() had special handling for a wrapped page->index + 1 = 0 case; but MAX_LFS_FILESIZE doesn't let us anywhere near there, and a corrupt page->index in the radix_tree could cause more trouble than that would catch. Remove that wrapped handling. invalidate_inode_pages2_range() uses min() to limit the pagevec_lookup when near the end of the range: copy that into the other two, although it's less useful than you might think (it limits the use of the buffer, rather than the indices looked up). Signed-off-by:
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Hugh Dickins authored
Use consistent variable names in truncate_pagecache(), truncate_setsize(), vmtruncate() and vmtruncate_range(). unmap_mapping_range() and vmtruncate_range() have mismatched interfaces: don't change either, but make the vmtruncates more precise about what they expect unmap_mapping_range() to do. vmtruncate_range() is currently called only with page-aligned start and end+1: can handle unaligned start, but unaligned end+1 would hit BUG_ON in truncate_inode_pages_range() (lacks partial clearing of the end page). Signed-off-by:
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Hugh Dickins authored
Correct comment on truncate_inode_pages*() in linux/mm.h; and remove declaration of page_unuse(), it didn't exist even in 2.2.26 or 2.4.0! Signed-off-by:
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Hugh Dickins authored
The often-NULL data arg to read_cache_page() and read_mapping_page() functions is misdescribed as "destination for read data": no, it's the first arg to the filler function, often struct file * to ->readpage(). Satisfy checkpatch.pl on those filler prototypes, and tidy up the declarations in linux/pagemap.h. Signed-off-by:
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