- 29 Apr, 2013 40 commits
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Joonsoo Kim authored
Now get_vmalloc_info() is in fs/proc/mmu.c. There is no reason that this code must be here and it's implementation needs vmlist_lock and it iterate a vmlist which may be internal data structure for vmalloc. It is preferable that vmlist_lock and vmlist is only used in vmalloc.c for maintainability. So move the code to vmalloc.c Signed-off-by:
Joonsoo Kim <js1304@gmail.com> Signed-off-by:
Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Dave Anderson <anderson@redhat.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Ingo Molnar <mingo@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Joonsoo Kim authored
This patchset removes vm_struct list management after initializing vmalloc. Adding and removing an entry to vmlist is linear time complexity, so it is inefficient. If we maintain this list, overall time complexity of adding and removing area to vmalloc space is O(N), although we use rbtree for finding vacant place and it's time complexity is just O(logN). And vmlist and vmlist_lock is used many places of outside of vmalloc.c. It is preferable that we hide this raw data structure and provide well-defined function for supporting them, because it makes that they cannot mistake when manipulating theses structure and it makes us easily maintain vmalloc layer. For kexec and makedumpfile, I export vmap_area_list, instead of vmlist. This comes from Atsushi's recommendation. For more information, please refer below link. https://lkml.org/lkml/2012/12/6/184 This patch: The purpose of iterating a vmlist is finding vm area with specific virtual address. find_vm_area() is provided for this purpose and more efficient, because it uses a rbtree. So change it. Signed-off-by:
Guan Xuetao <gxt@mprc.pku.edu.cn> Acked-by:
Ingo Molnar <mingo@kernel.org> Acked-by:
Chris Metcalf <cmetcalf@tilera.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp> Cc: Dave Anderson <anderson@redhat.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by:
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Darrick J. Wong authored
Walking a bio's page mappings has proved problematic, so create a new bio flag to indicate that a bio's data needs to be snapshotted in order to guarantee stable pages during writeback. Next, for the one user (ext3/jbd) of snapshotting, hook all the places where writes can be initiated without PG_writeback set, and set BIO_SNAP_STABLE there. We must also flag journal "metadata" bios for stable writeout, since file data can be written through the journal. Finally, the MS_SNAP_STABLE mount flag (only used by ext3) is now superfluous, so get rid of it. [akpm@linux-foundation.org: rename _submit_bh()'s `flags' to `bio_flags', delobotomize the _submit_bh declaration] [akpm@linux-foundation.org: teeny cleanup] Signed-off-by:
Darrick J. Wong <darrick.wong@oracle.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Artem Bityutskiy <dedekind1@gmail.com> Reviewed-by:
Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by:
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Gerald Schaefer authored
Commit abf09bed ("s390/mm: implement software dirty bits") introduced another difference in the pte layout vs. the pmd layout on s390, thoroughly breaking the s390 support for hugetlbfs. This requires replacing some more pte_xxx functions in mm/hugetlbfs.c with a huge_pte_xxx version. This patch introduces those huge_pte_xxx functions and their generic implementation in asm-generic/hugetlb.h, which will now be included on all architectures supporting hugetlbfs apart from s390. This change will be a no-op for those architectures. [akpm@linux-foundation.org: fix warning] Signed-off-by:
Gerald Schaefer <gerald.schaefer@de.ibm.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Hugh Dickins <hughd@google.com> Cc: Hillf Danton <dhillf@gmail.com> Acked-by: Michal Hocko <mhocko@suse.cz> [for !s390 parts] Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by:
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Josh Triplett authored
drop_caches.c provides code only invokable via sysctl, so don't compile it in when CONFIG_SYSCTL=n. Signed-off-by:
Josh Triplett <josh@joshtriplett.org> Acked-by:
Kees Cook <keescook@chromium.org> Signed-off-by:
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Michal Hocko authored
Now that we have generic and well ordered cgroup tree walkers there is no need to keep css_get_next in the place. Signed-off-by:
Michal Hocko <mhocko@suse.cz> Acked-by:
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by:
Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Ying Han <yinghan@google.com> Cc: Tejun Heo <htejun@gmail.com> Cc: Glauber Costa <glommer@parallels.com> Signed-off-by:
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Michal Hocko authored
mem_cgroup_iter basically does two things currently. It takes care of the house keeping (reference counting, raclaim cookie) and it iterates through a hierarchy tree (by using cgroup generic tree walk). The code would be much more easier to follow if we move the iteration outside of the function (to __mem_cgrou_iter_next) so the distinction is more clear. This patch doesn't introduce any functional changes. Signed-off-by:
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Michal Hocko authored
The current implementation of mem_cgroup_iter has to consider both css and memcg to find out whether no group has been found (css==NULL - aka the loop is completed) and that no memcg is associated with the found node (!memcg - aka css_tryget failed because the group is no longer alive). This leads to awkward tweaks like tests for css && !memcg to skip the current node. It will be much easier if we got rid off css variable altogether and only rely on memcg. In order to do that the iteration part has to skip dead nodes. This sounds natural to me and as a nice side effect we will get a simple invariant that memcg is always alive when non-NULL and all nodes have been visited otherwise. We could get rid of the surrounding while loop but keep it in for now to make review easier. It will go away in the following patch. Signed-off-by:
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Michal Hocko authored
Now that the per-node-zone-priority iterator caches memory cgroups rather than their css ids we have to be careful and remove them from the iterator when they are on the way out otherwise they might live for unbounded amount of time even though their group is already gone (until the global/targeted reclaim triggers the zone under priority to find out the group is dead and let it to find the final rest). We can fix this issue by relaxing rules for the last_visited memcg. Instead of taking a reference to the css before it is stored into iter->last_visited we can just store its pointer and track the number of removed groups from each memcg's subhierarchy. This number would be stored into iterator everytime when a memcg is cached. If the iter count doesn't match the curent walker root's one we will start from the root again. The group counter is incremented upwards the hierarchy every time a group is removed. The iter_lock can be dropped because racing iterators cannot leak the reference anymore as the reference count is not elevated for last_visited when it is cached. Locking rules got a bit complicated by this change though. The iterator primarily relies on rcu read lock which makes sure that once we see a valid last_visited pointer then it will be valid for the whole RCU walk. smp_rmb makes sure that dead_count is read before last_visited and last_dead_count while smp_wmb makes sure that last_visited is updated before last_dead_count so the up-to-date last_dead_count cannot point to an outdated last_visited. css_tryget then makes sure that the last_visited is still alive in case the iteration races with the cached group removal (css is invalidated before mem_cgroup_css_offline increments dead_count). In short: mem_cgroup_iter rcu_read_lock() dead_count = atomic_read(parent->dead_count) smp_rmb() if (dead_count != iter->last_dead_count) last_visited POSSIBLY INVALID -> last_visited = NULL if (!css_tryget(iter->last_visited)) last_visited DEAD -> last_visited = NULL next = find_next(last_visited) css_tryget(next) css_put(last_visited) // css would be invalidated and parent->dead_count // incremented if this was the last reference iter->last_visited = next smp_wmb() iter->last_dead_count = dead_count rcu_read_unlock() cgroup_rmdir cgroup_destroy_locked atomic_add(CSS_DEACT_BIAS, &css->refcnt) // subsequent css_tryget fail mem_cgroup_css_offline mem_cgroup_invalidate_reclaim_iterators while(parent = parent_mem_cgroup) atomic_inc(parent->dead_count) css_put(css) // last reference held by cgroup core Spotted by Ying Han. Original idea from Johannes Weiner. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by:Johannes Weiner <hannes@cmpxchg.org> Acked-by:
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Michal Hocko authored
mem_cgroup_iter curently relies on css->id when walking down a group hierarchy tree. This is really awkward because the tree walk depends on the groups creation ordering. The only guarantee is that a parent node is visited before its children. Example: 1) mkdir -p a a/d a/b/c 2) mkdir -a a/b/c a/d Will create the same trees but the tree walks will be different: 1) a, d, b, c 2) a, b, c, d Commit 574bd9f7 ("cgroup: implement generic child / descendant walk macros") has introduced generic cgroup tree walkers which provide either pre-order or post-order tree walk. This patch converts css->id based iteration to pre-order tree walk to keep the semantic with the original iterator where parent is always visited before its subtree. cgroup_for_each_descendant_pre suggests using post_create and pre_destroy for proper synchronization with groups addidition resp. removal. This implementation doesn't use those because a new memory cgroup is initialized sufficiently for iteration in mem_cgroup_css_alloc already and css reference counting enforces that the group is alive for both the last seen cgroup and the found one resp. it signals that the group is dead and it should be skipped. If the reclaim cookie is used we need to store the last visited group into the iterator so we have to be careful that it doesn't disappear in the mean time. Elevated reference count on the css keeps it alive even though the group have been removed (parked waiting for the last dput so that it can be freed). Per node-zone-prio iter_lock has been introduced to ensure that css_tryget and iter->last_visited is set atomically. Otherwise two racing walkers could both take a references and only one release it leading to a css leak (which pins cgroup dentry). Signed-off-by:
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Michal Hocko authored
The patchset tries to make mem_cgroup_iter saner in the way how it walks hierarchies. css->id based traversal is far from being ideal as it is not deterministic because it depends on the creation ordering. Additional to that css_id is considered a burden for cgroup maintainers because it is quite some code and memcg is the last user of it. After this series only the swap accounting uses css_id but that one will follow up later. Diffstat (if we exclude removed/added comments) looks quite promising. We got rid of some code: $ git diff mmotm... | grep -v "^[+-][[:space:]]*[/ ]\*" | diffstat b/include/linux/cgroup.h | 3 --- kernel/cgroup.c | 33 --------------------------------- mm/memcontrol.c | 4 +++- 3 files changed, 3 insertions(+), 37 deletions(-) The first patch is just preparatory and it changes when we release css of the previously returned memcg. Nothing controlversial. The second patch is the core of the patchset and it replaces css_get_next based on css_id by the generic cgroup pre-order. This brings some chalanges for the last visited group caching during the reclaim (mem_cgroup_per_zone::reclaim_iter). We have to use memcg pointers directly now which means that we have to keep a reference to those groups' css to keep them alive. I also folded iter_lock introduced by https://lkml.org/lkml/2013/1/3/295 in the previous version into this patch. Johannes felt the race I was describing should be mostly harmless and I haven't been able to trigger it so the lock doesn't deserve its own patch. It is still needed temporarily, though, because the reference counting on iter->last_visited depends on it. It will go away with the next patch. The next patch fixups an unbounded cgroup removal holdoff caused by the elevated css refcount. The issue has been observed by Ying Han. Johannes wasn't impressed by the previous version of the fix (https://lkml.org/lkml/2013/2/8/379) which cleaned up pending references during mem_cgroup_css_offline when a group is removed. He has suggested a different way when the iterator checks whether a cached memcg is still valid or no. More on that in the patch but the basic idea is that every memcg tracks the number removed subgroups and iterator records this number when a group is cached. These numbers are checked before iter->last_visited is about to be used and the iteration is restarted if it is invalid. The fourth and fifth patches are an attempt for simplification of the mem_cgroup_iter. css juggling is removed and the iteration logic is moved to a helper so that the reference counting and iteration are separated. The last patch just removes css_get_next as there is no user for it any longer. My testing looked as follows: A (use_hierarchy=1, limit_in_bytes=150M) /|\ 1 2 3 Children groups were created so that the number is never higher than 3 and their limits were random between 50-100M. Each group hosts a kernel build (starting with tar -xf so the tree is not shared and make -jNUM_CPUs/3) and terminated after random time - up to 5 minutes) and then it is removed. This should exercise both leaf and hierarchical reclaim as well as races with cgroup removals and debugging messages I added on top proved that. 100 groups were created during the test. This patch: css reference counting keeps the cgroup alive even though it has been already removed. mem_cgroup_iter relies on this fact and takes a reference to the returned group. The reference is then released on the next iteration or mem_cgroup_iter_break. mem_cgroup_iter currently releases the reference right after it gets the last css_id. This is correct because neither prev's memcg nor cgroup are accessed after then. This will change in the next patch so we need to hold the group alive a bit longer so let's move the css_put at the end of the function. Signed-off-by:
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Jiang Liu authored
Use helper function free_highmem_page() to free highmem pages into the buddy system. Signed-off-by:
Jiang Liu <jiang.liu@huawei.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Cong Wang <amwang@redhat.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Attilio Rao <attilio.rao@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by:
Pekka Enberg <penberg@kernel.org> Signed-off-by:
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Jiang Liu authored
Use helper function free_highmem_page() to free highmem pages into the buddy system. Signed-off-by:
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Jiang Liu authored
Use helper function free_highmem_page() to free highmem pages into the buddy system. Signed-off-by:
Sam Ravnborg <sam@ravnborg.org> Signed-off-by:
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Jiang Liu authored
Use helper function free_highmem_page() to free highmem pages into the buddy system. Signed-off-by:
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Jiang Liu authored
Use helper function free_highmem_page() to free highmem pages into the buddy system. Signed-off-by:
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Jiang Liu authored
Use helper function free_highmem_page() to free highmem pages into the buddy system. Signed-off-by:
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Jiang Liu authored
Use helper function free_highmem_page() to free highmem pages into the buddy system. Signed-off-by:
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Jiang Liu authored
Use helper function free_highmem_page() to free highmem pages into the buddy system. Also fix a bug that totalhigh_pages should be increased when freeing a highmem page into the buddy system. Signed-off-by:
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Jiang Liu authored
Use helper function free_highmem_page() to free highmem pages into the buddy system. Signed-off-by:
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Jiang Liu authored
The original goal of this patchset is to fix the bug reported by https://bugzilla.kernel.org/show_bug.cgi?id=53501 Now it has also been expanded to reduce common code used by memory initializion. This is the second part, which applies to the previous part at: http://marc.info/?l=linux-mm&m=136289696323825&w=2 It introduces a helper function free_highmem_page() to free highmem pages into the buddy system when initializing mm subsystem. Introduction of free_highmem_page() is one step forward to clean up accesses and modificaitons of totalhigh_pages, totalram_pages and zone->managed_pages etc. I hope we could remove all references to totalhigh_pages from the arch/ subdirectory. We have only tested these patchset on x86 platforms, and have done basic compliation tests using cross-compilers from ftp.kernel.org. That means some code may not pass compilation on some architectures. So any help to test this patchset are welcomed! There are several other parts still under development: Part3: refine code to manage totalram_pages, totalhigh_pages and zone->managed_pages Part4: introduce helper functions to simplify mem_init() and remove the global variable num_physpages. This patch: Introduce helper function free_highmem_page(), which will be used by architectures with HIGHMEM enabled to free highmem pages into the buddy system. Signed-off-by:
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Jiang Liu authored
Use common help functions to free reserved pages. Signed-off-by:
Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Signed-off-by:
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Jiang Liu authored
Use common help functions to free reserved pages. Signed-off-by:
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Jiang Liu authored
Use common help functions to free reserved pages. Signed-off-by:
Vineet Gupta <vgupta@synopsys.com> Signed-off-by:
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Jiang Liu authored
Use common help functions to free reserved pages. Signed-off-by:
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Jiang Liu authored
Use common help functions to free reserved pages. Signed-off-by:
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Jiang Liu authored
Use common help functions to free reserved pages. Signed-off-by:
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Jiang Liu authored
Use common help functions to free reserved pages. Signed-off-by:
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Jiang Liu authored
Use common help functions to free reserved pages. Signed-off-by:
Paul Mundt <lethal@linux-sh.org> Signed-off-by:
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Jiang Liu authored
Use common help functions to free reserved pages. Signed-off-by:
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Jiang Liu authored
Use common help functions to free reserved pages. Signed-off-by:
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Jiang Liu authored
Use common help functions to free reserved pages. Signed-off-by:
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Jiang Liu authored
Use common help functions to free reserved pages. Signed-off-by:
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Jiang Liu authored
Use common help functions to free reserved pages. Also include <asm/sections.h> to avoid local declarations. Signed-off-by:
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Jiang Liu authored
Use common help functions to free reserved pages. Signed-off-by:
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Jiang Liu authored
Use common help functions to free reserved pages. Signed-off-by:
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Jiang Liu authored
Use common help functions to free reserved pages. Signed-off-by:
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Jiang Liu authored
Use common help functions to free reserved pages. Signed-off-by:
Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by:
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Jiang Liu authored
Use common help functions to free reserved pages. Also include <asm/sections.h> to avoid local declarations. Signed-off-by:
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Jiang Liu authored
Use common help functions to free reserved pages. Signed-off-by:
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