linux/mm/vmalloc.c, branch v3.19

mm/vmalloc.c: fix memory ordering bug

2014-12-13T20:42:49Z

Read memory barriers must follow the read operations. Signed-off-by: Dmitry Vyukov Cc: Eric Dumazet Acked-by: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/vmalloc.c: replace printk with pr_warn

2014-12-11T01:41:05Z

This patch replaces printk(KERN_WARNING..) with pr_warn. Thus it also reduces one line extra because of formatting. Signed-off-by: Pintu Kumar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/vmalloc.c: use seq_open_private() instead of seq_open()

2014-10-10T02:25:56Z

Using seq_open_private() removes boilerplate code from vmalloc_open(). The resultant code is shorter and easier to follow. However, please note that seq_open_private() call kzalloc() rather than kmalloc() which may affect timing due to the memory initialisation overhead. Signed-off-by: Rob Jones Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/vmalloc.c: clean up map_vm_area third argument

2014-08-07T01:01:19Z

Currently map_vm_area() takes (struct page *** pages) as third argument, and after mapping, it moves (*pages) to point to (*pages + nr_mappped_pages). It looks like this kind of increment is useless to its caller these days. The callers don't care about the increments and actually they're trying to avoid this by passing another copy to map_vm_area(). The caller can always guarantee all the pages can be mapped into vm_area as specified in first argument and the caller only cares about whether map_vm_area() fails or not. This patch cleans up the pointer movement in map_vm_area() and updates its callers accordingly. Signed-off-by: WANG Chao Cc: Zhang Yanfei Acked-by: Greg Kroah-Hartman Cc: Minchan Kim Cc: Nitin Gupta Cc: Rusty Russell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm, vmalloc: constify allocation mask

2014-08-07T01:01:18Z

tmp_mask in the __vmalloc_area_node() iteration never changes so it can be moved into function scope and marked with const. This causes the movl and orl to only be done once per call rather than area->nr_pages times. nested_gfp can also be marked const. Signed-off-by: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/vmalloc.c: add a schedule point to vmalloc()

2014-08-07T01:01:18Z

It is not uncommon on busy servers to get stuck hundred of ms in vmalloc() calls (like file descriptor expansions). Add a cond_resched() to __vmalloc_area_node() to be gentle to other tasks. [akpm@linux-foundation.org: only do it for __GFP_WAIT, per David] Signed-off-by: Eric Dumazet Cc: Hugh Dickins Acked-by: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

vmalloc: use rcu list iterator to reduce vmap_area_lock contention

2014-08-07T01:01:15Z

Richard Yao reported a month ago that his system have a trouble with vmap_area_lock contention during performance analysis by /proc/meminfo. Andrew asked why his analysis checks /proc/meminfo stressfully, but he didn't answer it. https://lkml.org/lkml/2014/4/10/416 Although I'm not sure that this is right usage or not, there is a solution reducing vmap_area_lock contention with no side-effect. That is just to use rcu list iterator in get_vmalloc_info(). rcu can be used in this function because all RCU protocol is already respected by writers, since Nick Piggin commit db64fe02258f1 ("mm: rewrite vmap layer") back in linux-2.6.28 Specifically : insertions use list_add_rcu(), deletions use list_del_rcu() and kfree_rcu(). Note the rb tree is not used from rcu reader (it would not be safe), only the vmap_area_list has full RCU protection. Note that __purge_vmap_area_lazy() already uses this rcu protection. rcu_read_lock(); list_for_each_entry_rcu(va, &vmap_area_list, list) { if (va->flags & VM_LAZY_FREE) { if (va->va_start < *start) *start = va->va_start; if (va->va_end > *end) *end = va->va_end; nr += (va->va_end - va->va_start) >> PAGE_SHIFT; list_add_tail(&va->purge_list, &valist); va->flags |= VM_LAZY_FREEING; va->flags &= ~VM_LAZY_FREE; } } rcu_read_unlock(); Peter: : While rcu list traversal over the vmap_area_list is safe, this may : arrive at different results than the spinlocked version. The rcu list : traversal version will not be a 'snapshot' of a single, valid instant : of the entire vmap_area_list, but rather a potential amalgam of : different list states. Joonsoo: : Yes, you are right, but I don't think that we should be strict here. : Meminfo is already not a 'snapshot' at specific time. While we try to get : certain stats, the other stats can change. And, although we may arrive at : different results than the spinlocked version, the difference would not be : large and would not make serious side-effect. [edumazet@google.com: add more commit description] Signed-off-by: Joonsoo Kim Reported-by: Richard Yao Acked-by: Eric Dumazet Cc: Peter Hurley Cc: Zhang Yanfei Cc: Johannes Weiner Cc: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/vmalloc.c: export unmap_kernel_range()

2014-06-04T23:54:14Z

zsmalloc needs exported unmap_kernel_range for building as a module. See https://lkml.org/lkml/2013/1/18/487 I didn't send a patch to make unmap_kernel_range exportable at that time because zram was staging stuff and I thought VM function exporting for staging stuff makes no sense. Now zsmalloc was promoted. If we can't build zsmalloc as module, it means we can't build zram as module, either. Additionally, buddy map_vm_area is already exported so let's export unmap_kernel_range to help his buddy. Signed-off-by: Minchan Kim Cc: Nitin Gupta Cc: Sergey Senozhatsky Cc: Jerome Marchand Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/vmalloc.c: replace seq_printf by seq_puts

2014-06-04T23:54:04Z

Replace seq_printf where possible Signed-off-by: Fabian Frederick Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: replace __get_cpu_var uses with this_cpu_ptr

2014-06-04T23:54:03Z

Replace places where __get_cpu_var() is used for an address calculation with this_cpu_ptr(). Signed-off-by: Christoph Lameter Cc: Tejun Heo Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds