- May 09, 2017
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Michal Hocko authored
__vmalloc* allows users to provide gfp flags for the underlying allocation. This API is quite popular $ git grep "=[[:space:]]__vmalloc\|return[[:space:]]*__vmalloc" | wc -l 77 The only problem is that many people are not aware that they really want to give __GFP_HIGHMEM along with other flags because there is really no reason to consume precious lowmemory on CONFIG_HIGHMEM systems for pages which are mapped to the kernel vmalloc space. About half of users don't use this flag, though. This signals that we make the API unnecessarily too complex. This patch simply uses __GFP_HIGHMEM implicitly when allocating pages to be mapped to the vmalloc space. Current users which add __GFP_HIGHMEM are simplified and drop the flag. Link: http://lkml.kernel.org/r/20170307141020.29107-1-mhocko@kernel.org Signed-off-by:
Michal Hocko <mhocko@suse.com> Reviewed-by:
Matthew Wilcox <mawilcox@microsoft.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Cristopher Lameter <cl@linux.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Michal Hocko authored
__vmalloc_node_flags used to be static inline but this has changed by "mm: introduce kv[mz]alloc helpers" because kvmalloc_node needs to use it as well and the code is outside of the vmalloc proper. I haven't realized that changing this will lead to a subtle bug though. The function is responsible to track the caller as well. This caller is then printed by /proc/vmallocinfo. If __vmalloc_node_flags is not inline then we would get only direct users of __vmalloc_node_flags as callers (e.g. v[mz]alloc) which reduces usefulness of this debugging feature considerably. It simply doesn't help to see that the given range belongs to vmalloc as a caller: 0xffffc90002c79000-0xffffc90002c7d000 16384 vmalloc+0x16/0x18 pages=3 vmalloc N0=3 0xffffc90002c81000-0xffffc90002c85000 16384 vmalloc+0x16/0x18 pages=3 vmalloc N1=3 0xffffc90002c8d000-0xffffc90002c91000 16384 vmalloc+0x16/0x18 pages=3 vmalloc N1=3 0xffffc90002c95000-0xffffc90002c99000 16384 vmalloc+0x16/0x18 pages=3 vmalloc N1=3 We really want to catch the _caller_ of the vmalloc function. Fix this issue by making __vmalloc_node_flags static inline again. Link: http://lkml.kernel.org/r/20170502134657.12381-1-mhocko@kernel.org Signed-off-by:
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Michal Hocko authored
Patch series "kvmalloc", v5. There are many open coded kmalloc with vmalloc fallback instances in the tree. Most of them are not careful enough or simply do not care about the underlying semantic of the kmalloc/page allocator which means that a) some vmalloc fallbacks are basically unreachable because the kmalloc part will keep retrying until it succeeds b) the page allocator can invoke a really disruptive steps like the OOM killer to move forward which doesn't sound appropriate when we consider that the vmalloc fallback is available. As it can be seen implementing kvmalloc requires quite an intimate knowledge if the page allocator and the memory reclaim internals which strongly suggests that a helper should be implemented in the memory subsystem proper. Most callers, I could find, have been converted to use the helper instead. This is patch 6. There are some more relying on __GFP_REPEAT in the networking stack which I have converted as well and Eric Dumazet was not opposed [2] to convert them as well. [1] http://lkml.kernel.org/r/20170130094940.13546-1-mhocko@kernel.org [2] http://lkml.kernel.org/r/1485273626.16328.301.camel@edumazet-glaptop3.roam.corp.google.com This patch (of 9): Using kmalloc with the vmalloc fallback for larger allocations is a common pattern in the kernel code. Yet we do not have any common helper for that and so users have invented their own helpers. Some of them are really creative when doing so. Let's just add kv[mz]alloc and make sure it is implemented properly. This implementation makes sure to not make a large memory pressure for > PAGE_SZE requests (__GFP_NORETRY) and also to not warn about allocation failures. This also rules out the OOM killer as the vmalloc is a more approapriate fallback than a disruptive user visible action. This patch also changes some existing users and removes helpers which are specific for them. In some cases this is not possible (e.g. ext4_kvmalloc, libcfs_kvzalloc) because those seems to be broken and require GFP_NO{FS,IO} context which is not vmalloc compatible in general (note that the page table allocation is GFP_KERNEL). Those need to be fixed separately. While we are at it, document that __vmalloc{_node} about unsupported gfp mask because there seems to be a lot of confusion out there. kvmalloc_node will warn about GFP_KERNEL incompatible (which are not superset) flags to catch new abusers. Existing ones would have to die slowly. [sfr@canb.auug.org.au: f2fs fixup] Link: http://lkml.kernel.org/r/20170320163735.332e64b7@canb.auug.org.au Link: http://lkml.kernel.org/r/20170306103032.2540-2-mhocko@kernel.org Signed-off-by:
Stephen Rothwell <sfr@canb.auug.org.au> Reviewed-by: Andreas Dilger <adilger@dilger.ca> [ext4 part] Acked-by:
Vlastimil Babka <vbabka@suse.cz> Cc: John Hubbard <jhubbard@nvidia.com> Cc: David Miller <davem@davemloft.net> Signed-off-by:
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- Apr 02, 2017
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Mauro Carvalho Chehab authored
./lib/string.c:134: WARNING: Inline emphasis start-string without end-string. ./mm/filemap.c:522: WARNING: Inline interpreted text or phrase reference start-string without end-string. ./mm/filemap.c:1283: ERROR: Unexpected indentation. ./mm/filemap.c:3003: WARNING: Inline interpreted text or phrase reference start-string without end-string. ./mm/vmalloc.c:1544: WARNING: Inline emphasis start-string without end-string. ./mm/page_alloc.c:4245: ERROR: Unexpected indentation. ./ipc/util.c:676: ERROR: Unexpected indentation. ./drivers/pci/irq.c:35: WARNING: Block quote ends without a blank line; unexpected unindent. ./security/security.c:109: ERROR: Unexpected indentation. ./security/security.c:110: WARNING: Definition list ends without a blank line; unexpected unindent. ./block/genhd.c:275: WARNING: Inline strong start-string without end-string. ./block/genhd.c:283: WARNING: Inline strong start-string without end-string. ./include/linux/clk.h:134: WARNING: Inline emphasis start-string without end-string. ./include/linux/clk.h:134: WARNING: Inline emphasis start-string without end-string. ./ipc/util.c:477: ERROR: Unknown target name: "s". Signed-off-by:
Mauro Carvalho Chehab <mchehab@s-opensource.com> Acked-by:
Bjorn Helgaas <bhelgaas@google.com> Signed-off-by:
Jonathan Corbet <corbet@lwn.net>
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- Mar 18, 2017
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Thomas Garnier authored
This patch removes fixmap header usage on non-x86 code that was introduced by the adaptable MODULE_END change. Signed-off-by:
Thomas Garnier <thgarnie@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20170317175034.4701-1-thgarnie@google.com Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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- Mar 16, 2017
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Dmitry Vyukov authored
When vmalloc() fails it prints a very lengthy message with all the details about memory consumption assuming that it happened due to OOM. However, vmalloc() can also fail due to fatal signal pending. In such case the message is quite confusing because it suggests that it is OOM but the numbers suggest otherwise. The messages can also pollute console considerably. Don't warn when vmalloc() fails due to fatal signal pending. Link: http://lkml.kernel.org/r/20170313114425.72724-1-dvyukov@google.com Signed-off-by:
Dmitry Vyukov <dvyukov@google.com> Reviewed-by:
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by:
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Thomas Garnier authored
This patch aligns MODULES_END to the beginning of the fixmap section. It optimizes the space available for both sections. The address is pre-computed based on the number of pages required by the fixmap section. It will allow GDT remapping in the fixmap section. The current MODULES_END static address does not provide enough space for the kernel to support a large number of processors. Signed-off-by:
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- Mar 09, 2017
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Kirill A. Shutemov authored
Convert all non-architecture-specific code to 5-level paging. It's mostly mechanical adding handling one more page table level in places where we deal with pud_t. Signed-off-by:
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- Mar 03, 2017
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Ingo Molnar authored
sched/headers: Move task_struct::signal and task_struct::sighand types and accessors into <linux/sched/signal.h> task_struct::signal and task_struct::sighand are pointers, which would normally make it straightforward to not define those types in sched.h. That is not so, because the types are accompanied by a myriad of APIs (macros and inline functions) that dereference them. Split the types and the APIs out of sched.h and move them into a new header, <linux/sched/signal.h>. With this change sched.h does not know about 'struct signal' and 'struct sighand' anymore, trying to put accessors into sched.h as a test fails the following way: ./include/linux/sched.h: In function ‘test_signal_types’: ./include/linux/sched.h:2461:18: error: dereferencing pointer to incomplete type ‘struct signal_struct’ ^ This reduces the size and complexity of sched.h significantly. Update all headers and .c code that relied on getting the signal handling functionality from <linux/sched.h> to include <linux/sched/signal.h>. The list of affected files in the preparatory patch was partly generated by grepping for the APIs, and partly by doing coverage build testing, both all[yes|mod|def|no]config builds on 64-bit and 32-bit x86, and an array of cross-architecture builds. Nevertheless some (trivial) build breakage is still expected related to rare Kconfig combinations and in-flight patches to various kernel code, but most of it should be handled by this patch. Acked-by:
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- Feb 25, 2017
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Miles Chen authored
cleanup rest of dma_addr_t and phys_addr_t type casting in mm use %pad for dma_addr_t use %pa for phys_addr_t Link: http://lkml.kernel.org/r/1486618489-13912-1-git-send-email-miles.chen@mediatek.com Signed-off-by:
Miles Chen <miles.chen@mediatek.com> Signed-off-by:
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Michal Hocko authored
__vmalloc_area_node() allocates pages to cover the requested vmalloc size. This can be a lot of memory. If the current task is killed by the OOM killer, and thus has an unlimited access to memory reserves, it can consume all the memory theoretically. Fix this by checking for fatal_signal_pending and back off early. Link: http://lkml.kernel.org/r/20170201092706.9966-4-mhocko@kernel.org Signed-off-by:
Christoph Hellwig <hch@lst.de> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:
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- Feb 23, 2017
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Michal Hocko authored
warn_alloc is currently used for to report an allocation failure or an allocation stall. We print some details of the allocation request like the gfp mask and the request order. We do not print the allocation nodemask which is important when debugging the reason for the allocation failure as well. We alreaddy print the nodemask in the OOM report. Add nodemask to warn_alloc and print it in warn_alloc as well. Link: http://lkml.kernel.org/r/20170117091543.25850-3-mhocko@kernel.org Signed-off-by:
Mel Gorman <mgorman@suse.de> Acked-by:
Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Signed-off-by:
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Geliang Tang authored
Use rb_entry_safe() instead of open-coding it. Link: http://lkml.kernel.org/r/81bb9820e5b9e4a1c596b3e76f88abf8c4a76cb0.1482221947.git.geliangtang@gmail.com Signed-off-by:
Geliang Tang <geliangtang@gmail.com> Acked-by:
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- Dec 24, 2016
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Linus Torvalds authored
This was entirely automated, using the script by Al: PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>' sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \ $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h) to do the replacement at the end of the merge window. Requested-by:Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:
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- Dec 13, 2016
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Joel Fernandes authored
Use cond_resched_lock to avoid holding the vmap_area_lock for a potentially long time and thus creating bad latencies for various workloads. [hch: split from a larger patch by Joel, wrote the crappy changelog] Link: http://lkml.kernel.org/r/1479474236-4139-11-git-send-email-hch@lst.de Signed-off-by:
Joel Fernandes <joelaf@google.com> Signed-off-by:
Jisheng Zhang <jszhang@marvell.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: John Dias <joaodias@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by:
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Christoph Hellwig authored
The purge_lock spinlock causes high latencies with non RT kernel. This has been reported multiple times on lkml [1] [2] and affects applications like audio. This patch replaces it with a mutex to allow preemption while holding the lock. Thanks to Joel Fernandes for the detailed report and analysis as well as an earlier attempt at fixing this issue. [1] http://lists.openwall.net/linux-kernel/2016/03/23/29 [2] https://lkml.org/lkml/2016/10/9/59 Link: http://lkml.kernel.org/r/1479474236-4139-10-git-send-email-hch@lst.de Signed-off-by:
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Christoph Hellwig authored
We will take a sleeping lock in later in this series, so this adds the proper safeguards. Link: http://lkml.kernel.org/r/1479474236-4139-9-git-send-email-hch@lst.de Signed-off-by:
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Andrey Ryabinin authored
We are going to use sleeping lock for freeing vmap. However some vfree() users want to free memory from atomic (but not from interrupt) context. For this we add vfree_atomic() - deferred variation of vfree() which can be used in any atomic context (except NMIs). [akpm@linux-foundation.org: tweak comment grammar] [aryabinin@virtuozzo.com: use raw_cpu_ptr() instead of this_cpu_ptr()] Link: http://lkml.kernel.org/r/1481553981-3856-1-git-send-email-aryabinin@virtuozzo.com Link: http://lkml.kernel.org/r/1479474236-4139-5-git-send-email-hch@lst.de Signed-off-by:
Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by:
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Christoph Hellwig authored
Move the purge_lock synchronization to the callers, move the call to purge_fragmented_blocks_allcpus at the beginning of the function to the callers that need it, move the force_flush behavior to the caller that needs it, and pass start and end by value instead of by reference. No change in behavior. Link: http://lkml.kernel.org/r/1479474236-4139-4-git-send-email-hch@lst.de Signed-off-by:
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Christoph Hellwig authored
Just inline it into the only caller. Link: http://lkml.kernel.org/r/1479474236-4139-3-git-send-email-hch@lst.de Signed-off-by:
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Christoph Hellwig authored
Patch series "reduce latency in __purge_vmap_area_lazy", v2. This patch (of 10): Sort out the long lock hold times in __purge_vmap_area_lazy. It is based on a patch from Joel. Inline free_unmap_vmap_area_noflush() it into the only caller. Link: http://lkml.kernel.org/r/1479474236-4139-2-git-send-email-hch@lst.de Signed-off-by:
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zijun_hu authored
Many seq_file helpers exist for simplifying implementation of virtual files especially, for /proc nodes. however, the helpers for iteration over list_head are available but aren't adopted to implement /proc/vmallocinfo currently. Simplify /proc/vmallocinfo implementation by using existing seq_file helpers. Link: http://lkml.kernel.org/r/57FDF2E5.1000201@zoho.com Signed-off-by:
zijun_hu <zijun_hu@htc.com> Acked-by:
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- Oct 08, 2016
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Michal Hocko authored
warn_alloc_failed is currently used from the page and vmalloc allocators. This is a good reuse of the code except that vmalloc would appreciate a slightly different warning message. This is already handled by the fmt parameter except that "%s: page allocation failure: order:%u, mode:%#x(%pGg)" is printed anyway. This might be quite misleading because it might be a vmalloc failure which leads to the warning while the page allocator is not the culprit here. Fix this by always using the fmt string and only print the context that makes sense for the particular context (e.g. order makes only very little sense for the vmalloc context). Rename the function to not miss any user and also because a later patch will reuse it also for !failure cases. Link: http://lkml.kernel.org/r/20160929084407.7004-2-mhocko@kernel.org Signed-off-by:
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zijun_hu authored
It causes double align requirement for __get_vm_area_node() if parameter size is power of 2 and VM_IOREMAP is set in parameter flags, for example size=0x10000 -> fls_long(0x10000)=17 -> align=0x20000 get_count_order_long() is implemented and can be used instead of fls_long() for fixing the bug, for example size=0x10000 -> get_count_order_long(0x10000)=16 -> align=0x10000 [akpm@linux-foundation.org: s/get_order_long()/get_count_order_long()/] [zijun_hu@zoho.com: fixes] Link: http://lkml.kernel.org/r/57AABC8B.1040409@zoho.com [akpm@linux-foundation.org: locate get_count_order_long() next to get_count_order()] [akpm@linux-foundation.org: move get_count_order[_long] definitions to pick up fls_long()] [zijun_hu@htc.com: move out get_count_order[_long]() from __KERNEL__ scope] Link: http://lkml.kernel.org/r/57B2C4CE.80303@zoho.com Link: http://lkml.kernel.org/r/fc045ecf-20fa-0722-b3ac-9a6140488fad@zoho.com Signed-off-by:
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- Jul 26, 2016
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Vladimir Davydov authored
Currently, to charge a non-slab allocation to kmemcg one has to use alloc_kmem_pages helper with __GFP_ACCOUNT flag. A page allocated with this helper should finally be freed using free_kmem_pages, otherwise it won't be uncharged. This API suits its current users fine, but it turns out to be impossible to use along with page reference counting, i.e. when an allocation is supposed to be freed with put_page, as it is the case with pipe or unix socket buffers. To overcome this limitation, this patch moves charging/uncharging to generic page allocator paths, i.e. to __alloc_pages_nodemask and free_pages_prepare, and zaps alloc/free_kmem_pages helpers. This way, one can use any of the available page allocation functions to get the allocated page charged to kmemcg - it's enough to pass __GFP_ACCOUNT, just like in case of kmalloc and friends. A charged page will be automatically uncharged on free. To make it possible, we need to mark pages charged to kmemcg somehow. To avoid introducing a new page flag, we make use of page->_mapcount for marking such pages. Since pages charged to kmemcg are not supposed to be mapped to userspace, it should work just fine. There are other (ab)users of page->_mapcount - buddy and balloon pages - but we don't conflict with them. In case kmemcg is compiled out or not used at runtime, this patch introduces no overhead to generic page allocator paths. If kmemcg is used, it will be plus one gfp flags check on alloc and plus one page->_mapcount check on free, which shouldn't hurt performance, because the data accessed are hot. Link: http://lkml.kernel.org/r/a9736d856f895bcb465d9f257b54efe32eda6f99.1464079538.git.vdavydov@virtuozzo.com Signed-off-by:
Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by:
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- Jun 03, 2016
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Guillermo Julián Moreno authored
When remapping pages accounting for 4G or more memory space, the operation 'count << PAGE_SHIFT' overflows as it is performed on an integer. Solution: cast before doing the bitshift. [akpm@linux-foundation.org: fix vm_unmap_ram() also] [akpm@linux-foundation.org: fix vmap() as well, per Guillermo] Link: http://lkml.kernel.org/r/etPan.57175fb3.7a271c6b.2bd@naudit.es Signed-off-by:
Guillermo Julián Moreno <guillermo.julian@naudit.es> Signed-off-by:
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- May 21, 2016
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Chris Wilson authored
When mixing lots of vmallocs and set_memory_*() (which calls vm_unmap_aliases()) I encountered situations where the performance degraded severely due to the walking of the entire vmap_area list each invocation. One simple improvement is to add the lazily freed vmap_area to a separate lockless free list, such that we then avoid having to walk the full list on each purge. Signed-off-by:
Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by:
Roman Pen <r.peniaev@gmail.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Roman Pen <r.peniaev@gmail.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Toshi Kani <toshi.kani@hp.com> Cc: Shawn Lin <shawn.lin@rock-chips.com> Signed-off-by:
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- Apr 05, 2016
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Chris Wilson authored
vmaps are temporary kernel mappings that may be of long duration. Reusing a vmap on an object is preferrable for a driver as the cost of setting up the vmap can otherwise dominate the operation on the object. However, the vmap address space is rather limited on 32bit systems and so we add a notification for vmap pressure in order for the driver to release any cached vmappings. The interface is styled after the oom-notifier where the callees are passed a pointer to an unsigned long counter for them to indicate if they have freed any space. v2: Guard the blocking notifier call with gfpflags_allow_blocking() v3: Correct typo in forward declaration and move to head of file Signed-off-by:
Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
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- Mar 17, 2016
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Shawn Lin authored
We have PAGE_ALIGNED() in mm.h, so let's use it instead of IS_ALIGNED() for checking PAGE_SIZE aligned case. Signed-off-by:
Shawn Lin <shawn.lin@rock-chips.com> Signed-off-by:
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Joe Perches authored
Kernel style prefers a single string over split strings when the string is 'user-visible'. Miscellanea: - Add a missing newline - Realign arguments Signed-off-by:
Joe Perches <joe@perches.com> Acked-by: Tejun Heo <tj@kernel.org> [percpu] Signed-off-by:
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Joonsoo Kim authored
As CONFIG_DEBUG_PAGEALLOC can be enabled/disabled via kernel parameters we can optimize some cases by checking the enablement state. This is follow-up work for Christian's Optimize CONFIG_DEBUG_PAGEALLOC: https://lkml.org/lkml/2016/1/27/194 Remaining work is to make sparc to be aware of this but it looks not easy for me so I skip that in this series. This patch (of 5): We can disable debug_pagealloc processing even if the code is complied with CONFIG_DEBUG_PAGEALLOC. This patch changes the code to query whether it is enabled or not in runtime. [akpm@linux-foundation.org: update comment, per David. Adjust comment to use 80 cols] Signed-off-by:
Joonsoo Kim <iamjoonsoo.kim@lge.com> Reviewed-by:
Christian Borntraeger <borntraeger@de.ibm.com> Acked-by:
David Rientjes <rientjes@google.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Takashi Iwai <tiwai@suse.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Signed-off-by:
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- Jan 16, 2016
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Wang Xiaoqiang authored
Just cleanup, no functional change. Signed-off-by:
Wang Xiaoqiang <wangxq10@lzu.edu.cn> Signed-off-by:
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- Jan 15, 2016
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David Rientjes authored
VM_VPAGES is unnecessary, it's easier to check is_vmalloc_addr() when reading /proc/vmallocinfo. [akpm@linux-foundation.org: remove VM_VPAGES reference via kvfree()] Signed-off-by:
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Geliang Tang authored
To make the intention clearer, use list_{next,first}_entry instead of list_entry. Signed-off-by:Geliang Tang <geliangtang@163.com> Signed-off-by:
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Vladimir Davydov authored
Make vmalloc family functions allocate vmalloc area pages with alloc_kmem_pages so that if __GFP_ACCOUNT is set they will be accounted to memcg. This is needed, at least, to account alloc_fdmem allocations. Signed-off-by:
Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Greg Thelen <gthelen@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by:
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- Nov 21, 2015
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Jerome Marchand authored
Commit 71394fe5 ("mm: vmalloc: add flag preventing guard hole allocation") missed a spot. Currently remove_vm_area() decreases vm->size to "remove" the guard hole page, even when it isn't present. All but one users just free the vm_struct rigth away and never access vm->size anyway. Don't touch the size in remove_vm_area() and have __vunmap() use the proper get_vm_area_size() helper. Signed-off-by:
Jerome Marchand <jmarchan@redhat.com> Acked-by:
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- Nov 07, 2015
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Mel Gorman authored
Andrew stated the following We have quite a history of remote parts of the kernel using weird/wrong/inexplicable combinations of __GFP_ flags. I tend to think that this is because we didn't adequately explain the interface. And I don't think that gfp.h really improved much in this area as a result of this patchset. Could you go through it some time and decide if we've adequately documented all this stuff? This patches first moves some GFP flag combinations that are part of the MM internals to mm/internal.h. The rest of the patch documents the __GFP_FOO bits under various headings and then documents the flag combinations. It will not help callers that are brain damaged but the clarity might motivate some fixes and avoid future mistakes. Signed-off-by:
Mel Gorman <mgorman@techsingularity.net> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Rik van Riel <riel@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vitaly Wool <vitalywool@gmail.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by:
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Mel Gorman authored
mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd __GFP_WAIT has been used to identify atomic context in callers that hold spinlocks or are in interrupts. They are expected to be high priority and have access one of two watermarks lower than "min" which can be referred to as the "atomic reserve". __GFP_HIGH users get access to the first lower watermark and can be called the "high priority reserve". Over time, callers had a requirement to not block when fallback options were available. Some have abused __GFP_WAIT leading to a situation where an optimisitic allocation with a fallback option can access atomic reserves. This patch uses __GFP_ATOMIC to identify callers that are truely atomic, cannot sleep and have no alternative. High priority users continue to use __GFP_HIGH. __GFP_DIRECT_RECLAIM identifies callers that can sleep and are willing to enter direct reclaim. __GFP_KSWAPD_RECLAIM to identify callers that want to wake kswapd for background reclaim. __GFP_WAIT is redefined as a caller that is willing to enter direct reclaim and wake kswapd for background reclaim. This patch then converts a number of sites o __GFP_ATOMIC is used by callers that are high priority and have memory pools for those requests. GFP_ATOMIC uses this flag. o Callers that have a limited mempool to guarantee forward progress clear __GFP_DIRECT_RECLAIM but keep __GFP_KSWAPD_RECLAIM. bio allocations fall into this category where kswapd will still be woken but atomic reserves are not used as there is a one-entry mempool to guarantee progress. o Callers that are checking if they are non-blocking should use the helper gfpflags_allow_blocking() where possible. This is because checking for __GFP_WAIT as was done historically now can trigger false positives. Some exceptions like dm-crypt.c exist where the code intent is clearer if __GFP_DIRECT_RECLAIM is used instead of the helper due to flag manipulations. o Callers that built their own GFP flags instead of starting with GFP_KERNEL and friends now also need to specify __GFP_KSWAPD_RECLAIM. The first key hazard to watch out for is callers that removed __GFP_WAIT and was depending on access to atomic reserves for inconspicuous reasons. In some cases it may be appropriate for them to use __GFP_HIGH. The second key hazard is callers that assembled their own combination of GFP flags instead of starting with something like GFP_KERNEL. They may now wish to specify __GFP_KSWAPD_RECLAIM. It's almost certainly harmless if it's missed in most cases as other activity will wake kswapd. Signed-off-by:
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- Nov 06, 2015
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Alexander Kuleshov authored
linux/mm.h provides offset_in_page() macro. Let's use already predefined macro instead of (addr & ~PAGE_MASK). Signed-off-by:
Alexander Kuleshov <kuleshovmail@gmail.com> Signed-off-by:
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- Nov 02, 2015
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Linus Torvalds authored
It turns out that at least some versions of glibc end up reading /proc/meminfo at every single startup, because glibc wants to know the amount of memory the machine has. And while that's arguably insane, it's just how things are. And it turns out that it's not all that expensive most of the time, but the vmalloc information statistics (amount of virtual memory used in the vmalloc space, and the biggest remaining chunk) can be rather expensive to compute. The 'get_vmalloc_info()' function actually showed up on my profiles as 4% of the CPU usage of "make test" in the git source repository, because the git tests are lots of very short-lived shell-scripts etc. It turns out that apparently this same silly vmalloc info gathering shows up on the facebook servers too, according to Dave Jones. So it's not just "make test" for git. We had two patches to just cache the information (one by me, one by Ingo) to mitigate this issue, but the whole vmalloc information of of rather dubious value to begin with, and people who *actually* want to know what the situation is wrt the vmalloc area should just look at the much more complete /proc/vmallocinfo instead. In fact, according to my testing - and perhaps more importantly, according to that big search engine in the sky: Google - there is nothing out there that actually cares about those two expensive fields: VmallocUsed and VmallocChunk. So let's try to just remove them entirely. Actually, this just removes the computation and reports the numbers as zero for now, just to try to be minimally intrusive. If this breaks anything, we'll obviously have to re-introduce the code to compute this all and add the caching patches on top. But if given the option, I'd really prefer to just remove this bad idea entirely rather than add even more code to work around our historical mistake that likely nobody really cares about. Signed-off-by:
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