- 25 7月, 2008 13 次提交
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由 Andi Kleen 提交于
Add the ability to configure the hugetlb hstate used on a per mount basis. - Add a new pagesize= option to the hugetlbfs mount that allows setting the page size - This option causes the mount code to find the hstate corresponding to the specified size, and sets up a pointer to the hstate in the mount's superblock. - Change the hstate accessors to use this information rather than the global_hstate they were using (requires a slight change in mm/memory.c so we don't NULL deref in the error-unmap path -- see comments). [np: take hstate out of hugetlbfs inode and vma->vm_private_data] Acked-by: NAdam Litke <agl@us.ibm.com> Acked-by: NNishanth Aravamudan <nacc@us.ibm.com> Signed-off-by: NAndi Kleen <ak@suse.de> Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Andi Kleen 提交于
Add basic support for more than one hstate in hugetlbfs. This is the key to supporting multiple hugetlbfs page sizes at once. - Rather than a single hstate, we now have an array, with an iterator - default_hstate continues to be the struct hstate which we use by default - Add functions for architectures to register new hstates [akpm@linux-foundation.org: coding-style fixes] Acked-by: NAdam Litke <agl@us.ibm.com> Acked-by: NNishanth Aravamudan <nacc@us.ibm.com> Signed-off-by: NAndi Kleen <ak@suse.de> Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Andi Kleen 提交于
The goal of this patchset is to support multiple hugetlb page sizes. This is achieved by introducing a new struct hstate structure, which encapsulates the important hugetlb state and constants (eg. huge page size, number of huge pages currently allocated, etc). The hstate structure is then passed around the code which requires these fields, they will do the right thing regardless of the exact hstate they are operating on. This patch adds the hstate structure, with a single global instance of it (default_hstate), and does the basic work of converting hugetlb to use the hstate. Future patches will add more hstate structures to allow for different hugetlbfs mounts to have different page sizes. [akpm@linux-foundation.org: coding-style fixes] Acked-by: NAdam Litke <agl@us.ibm.com> Acked-by: NNishanth Aravamudan <nacc@us.ibm.com> Signed-off-by: NAndi Kleen <ak@suse.de> Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Andi Kleen 提交于
Needed to avoid code duplication in follow up patches. Acked-by: NAdam Litke <agl@us.ibm.com> Acked-by: NNishanth Aravamudan <nacc@us.ibm.com> Signed-off-by: NAndi Kleen <ak@suse.de> Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Johannes Weiner 提交于
Hugh adds: vma_pagecache_offset() has a dangerously misleading name, since it's using hugepage units: rename it to vma_hugecache_offset(). [apw@shadowen.org: restack onto fixed MAP_PRIVATE reservations] [akpm@linux-foundation.org: vma_split conversion] Signed-off-by: NJohannes Weiner <hannes@saeurebad.de> Signed-off-by: NHugh Dickins <hugh@veritas.com> Cc: Adam Litke <agl@us.ibm.com> Cc: Nishanth Aravamudan <nacc@us.ibm.com> Cc: Andi Kleen <ak@suse.de> Cc: Nick Piggin <npiggin@suse.de> Signed-off-by: NAndy Whitcroft <apw@shadowen.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Andy Whitcroft 提交于
When a hugetlb mapping with a reservation is split, a new VMA is cloned from the original. This new VMA is a direct copy of the original including the reservation count. When this pair of VMAs are unmapped we will incorrect double account the unused reservation and the overall reservation count will be incorrect, in extreme cases it will wrap. The problem occurs when we split an existing VMA say to unmap a page in the middle. split_vma() will create a new VMA copying all fields from the original. As we are storing our reservation count in vm_private_data this is also copies, endowing the new VMA with a duplicate of the original VMA's reservation. Neither of the new VMAs can exhaust these reservations as they are too small, but when we unmap and close these VMAs we will incorrect credit the remainder twice and resv_huge_pages will become out of sync. This can lead to allocation failures on mappings with reservations and even to resv_huge_pages wrapping which prevents all subsequent hugepage allocations. The simple fix would be to correctly apportion the remaining reservation count when the split is made. However the only hook we have vm_ops->open only has the new VMA we do not know the identity of the preceeding VMA. Also even if we did have that VMA to hand we do not know how much of the reservation was consumed each side of the split. This patch therefore takes a different tack. We know that the whole of any private mapping (which has a reservation) has a reservation over its whole size. Any present pages represent consumed reservation. Therefore if we track the instantiated pages we can calculate the remaining reservation. This patch reuses the existing regions code to track the regions for which we have consumed reservation (ie. the instantiated pages), as each page is faulted in we record the consumption of reservation for the new page. When we need to return unused reservations at unmap time we simply count the consumed reservation region subtracting that from the whole of the map. During a VMA split the newly opened VMA will point to the same region map, as this map is offset oriented it remains valid for both of the split VMAs. This map is referenced counted so that it is removed when all VMAs which are part of the mmap are gone. Thanks to Adam Litke and Mel Gorman for their review feedback. Signed-off-by: NAndy Whitcroft <apw@shadowen.org> Acked-by: NMel Gorman <mel@csn.ul.ie> Cc: Adam Litke <agl@us.ibm.com> Cc: Johannes Weiner <hannes@saeurebad.de> Cc: Andy Whitcroft <apw@shadowen.org> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Cc: Jon Tollefson <kniht@linux.vnet.ibm.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Andy Whitcroft 提交于
By default all shared mappings and most private mappings now have reservations associated with them. This improves semantics by providing allocation guarentees to the mapper. However a small number of applications may attempt to make very large sparse mappings, with these strict reservations the system will never be able to honour the mapping. This patch set brings MAP_NORESERVE support to hugetlb files. This allows new mappings to be made to hugetlbfs files without an associated reservation, for both shared and private mappings. This allows applications which want to create very sparse mappings to opt-out of the reservation system. Obviously as there is no reservation they are liable to fault at runtime if the huge page pool becomes exhausted; buyer beware. Signed-off-by: NAndy Whitcroft <apw@shadowen.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Adam Litke <agl@us.ibm.com> Cc: Johannes Weiner <hannes@saeurebad.de> Cc: Andy Whitcroft <apw@shadowen.org> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Andy Whitcroft 提交于
The following patch will require use of the reservation regions support. Move this earlier in the file. No changes have been made to this code. Signed-off-by: NAndy Whitcroft <apw@shadowen.org> Cc: Mel Gorman <mel@csn.ul.ie> Acked-by: NAdam Litke <agl@us.ibm.com> Cc: Johannes Weiner <hannes@saeurebad.de> Cc: Andy Whitcroft <apw@shadowen.org> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Andy Whitcroft 提交于
Create some new accessors for vma private data to cut down on and contain the casts. Encapsulates the huge and small page offset calculations. Also adds a couple of VM_BUG_ONs for consistency. [akpm@linux-foundation.org: Make things static] Signed-off-by: NAndy Whitcroft <apw@shadowen.org> Acked-by: NMel Gorman <mel@csn.ul.ie> Cc: Adam Litke <agl@us.ibm.com> Cc: Johannes Weiner <hannes@saeurebad.de> Cc: Andy Whitcroft <apw@shadowen.org> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Mel Gorman 提交于
hugetlb: guarantee that COW faults for a process that called mmap(MAP_PRIVATE) on hugetlbfs will succeed After patch 2 in this series, a process that successfully calls mmap() for a MAP_PRIVATE mapping will be guaranteed to successfully fault until a process calls fork(). At that point, the next write fault from the parent could fail due to COW if the child still has a reference. We only reserve pages for the parent but a copy must be made to avoid leaking data from the parent to the child after fork(). Reserves could be taken for both parent and child at fork time to guarantee faults but if the mapping is large it is highly likely we will not have sufficient pages for the reservation, and it is common to fork only to exec() immediatly after. A failure here would be very undesirable. Note that the current behaviour of mainline with MAP_PRIVATE pages is pretty bad. The following situation is allowed to occur today. 1. Process calls mmap(MAP_PRIVATE) 2. Process calls mlock() to fault all pages and makes sure it succeeds 3. Process forks() 4. Process writes to MAP_PRIVATE mapping while child still exists 5. If the COW fails at this point, the process gets SIGKILLed even though it had taken care to ensure the pages existed This patch improves the situation by guaranteeing the reliability of the process that successfully calls mmap(). When the parent performs COW, it will try to satisfy the allocation without using reserves. If that fails the parent will steal the page leaving any children without a page. Faults from the child after that point will result in failure. If the child COW happens first, an attempt will be made to allocate the page without reserves and the child will get SIGKILLed on failure. To summarise the new behaviour: 1. If the original mapper performs COW on a private mapping with multiple references, it will attempt to allocate a hugepage from the pool or the buddy allocator without using the existing reserves. On fail, VMAs mapping the same area are traversed and the page being COW'd is unmapped where found. It will then steal the original page as the last mapper in the normal way. 2. The VMAs the pages were unmapped from are flagged to note that pages with data no longer exist. Future no-page faults on those VMAs will terminate the process as otherwise it would appear that data was corrupted. A warning is printed to the console that this situation occured. 2. If the child performs COW first, it will attempt to satisfy the COW from the pool if there are enough pages or via the buddy allocator if overcommit is allowed and the buddy allocator can satisfy the request. If it fails, the child will be killed. If the pool is large enough, existing applications will not notice that the reserves were a factor. Existing applications depending on the no-reserves been set are unlikely to exist as for much of the history of hugetlbfs, pages were prefaulted at mmap(), allocating the pages at that point or failing the mmap(). [npiggin@suse.de: fix CONFIG_HUGETLB=n build] Signed-off-by: NMel Gorman <mel@csn.ul.ie> Acked-by: NAdam Litke <agl@us.ibm.com> Cc: Andy Whitcroft <apw@shadowen.org> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Mel Gorman 提交于
This patch reserves huge pages at mmap() time for MAP_PRIVATE mappings in a similar manner to the reservations taken for MAP_SHARED mappings. The reserve count is accounted both globally and on a per-VMA basis for private mappings. This guarantees that a process that successfully calls mmap() will successfully fault all pages in the future unless fork() is called. The characteristics of private mappings of hugetlbfs files behaviour after this patch are; 1. The process calling mmap() is guaranteed to succeed all future faults until it forks(). 2. On fork(), the parent may die due to SIGKILL on writes to the private mapping if enough pages are not available for the COW. For reasonably reliable behaviour in the face of a small huge page pool, children of hugepage-aware processes should not reference the mappings; such as might occur when fork()ing to exec(). 3. On fork(), the child VMAs inherit no reserves. Reads on pages already faulted by the parent will succeed. Successful writes will depend on enough huge pages being free in the pool. 4. Quotas of the hugetlbfs mount are checked at reserve time for the mapper and at fault time otherwise. Before this patch, all reads or writes in the child potentially needs page allocations that can later lead to the death of the parent. This applies to reads and writes of uninstantiated pages as well as COW. After the patch it is only a write to an instantiated page that causes problems. Signed-off-by: NMel Gorman <mel@csn.ul.ie> Acked-by: NAdam Litke <agl@us.ibm.com> Cc: Andy Whitcroft <apw@shadowen.org> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Mel Gorman 提交于
This is a patchset to give reliable behaviour to a process that successfully calls mmap(MAP_PRIVATE) on a hugetlbfs file. Currently, it is possible for the process to be killed due to a small hugepage pool size even if it calls mlock(). MAP_SHARED mappings on hugetlbfs reserve huge pages at mmap() time. This guarantees all future faults against the mapping will succeed. This allows local allocations at first use improving NUMA locality whilst retaining reliability. MAP_PRIVATE mappings do not reserve pages. This can result in an application being SIGKILLed later if a huge page is not available at fault time. This makes huge pages usage very ill-advised in some cases as the unexpected application failure cannot be detected and handled as it is immediately fatal. Although an application may force instantiation of the pages using mlock(), this may lead to poor memory placement and the process may still be killed when performing COW. This patchset introduces a reliability guarantee for the process which creates a private mapping, i.e. the process that calls mmap() on a hugetlbfs file successfully. The first patch of the set is purely mechanical code move to make later diffs easier to read. The second patch will guarantee faults up until the process calls fork(). After patch two, as long as the child keeps the mappings, the parent is no longer guaranteed to be reliable. Patch 3 guarantees that the parent will always successfully COW by unmapping the pages from the child in the event there are insufficient pages in the hugepage pool in allocate a new page, be it via a static or dynamic pool. Existing hugepage-aware applications are unlikely to be affected by this change. For much of hugetlbfs's history, pages were pre-faulted at mmap() time or mmap() failed which acts in a reserve-like manner. If the pool is sized correctly already so that parent and child can fault reliably, the application will not even notice the reserves. It's only when the pool is too small for the application to function perfectly reliably that the reserves come into play. Credit goes to Andy Whitcroft for cleaning up a number of mistakes during review before the patches were released. This patch: A later patch in this set needs to call hugetlb_acct_memory() before it is defined. This patch moves the function without modification. This makes later diffs easier to read. Signed-off-by: NMel Gorman <mel@csn.ul.ie> Acked-by: NAdam Litke <agl@us.ibm.com> Cc: Andy Whitcroft <apw@shadowen.org> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Adrian Bunk 提交于
It's confusing that set_max_huge_pages() contained two different variables named "ret", and although the code works correctly this should be fixed. The inner of the two variables can simply be removed. Spotted by sparse. Signed-off-by: NAdrian Bunk <bunk@kernel.org> Cc: "KOSAKI Motohiro" <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 07 6月, 2008 1 次提交
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由 Nick Piggin 提交于
============================================= [ INFO: possible recursive locking detected ] 2.6.26-rc4 #30 --------------------------------------------- heap-overflow/2250 is trying to acquire lock: (&mm->page_table_lock){--..}, at: [<c0000000000cf2e8>] .copy_hugetlb_page_range+0x108/0x280 but task is already holding lock: (&mm->page_table_lock){--..}, at: [<c0000000000cf2dc>] .copy_hugetlb_page_range+0xfc/0x280 other info that might help us debug this: 3 locks held by heap-overflow/2250: #0: (&mm->mmap_sem){----}, at: [<c000000000050e44>] .dup_mm+0x134/0x410 #1: (&mm->mmap_sem/1){--..}, at: [<c000000000050e54>] .dup_mm+0x144/0x410 #2: (&mm->page_table_lock){--..}, at: [<c0000000000cf2dc>] .copy_hugetlb_page_range+0xfc/0x280 stack backtrace: Call Trace: [c00000003b2774e0] [c000000000010ce4] .show_stack+0x74/0x1f0 (unreliable) [c00000003b2775a0] [c0000000003f10e0] .dump_stack+0x20/0x34 [c00000003b277620] [c0000000000889bc] .__lock_acquire+0xaac/0x1080 [c00000003b277740] [c000000000089000] .lock_acquire+0x70/0xb0 [c00000003b2777d0] [c0000000003ee15c] ._spin_lock+0x4c/0x80 [c00000003b277870] [c0000000000cf2e8] .copy_hugetlb_page_range+0x108/0x280 [c00000003b277950] [c0000000000bcaa8] .copy_page_range+0x558/0x790 [c00000003b277ac0] [c000000000050fe0] .dup_mm+0x2d0/0x410 [c00000003b277ba0] [c000000000051d24] .copy_process+0xb94/0x1020 [c00000003b277ca0] [c000000000052244] .do_fork+0x94/0x310 [c00000003b277db0] [c000000000011240] .sys_clone+0x60/0x80 [c00000003b277e30] [c0000000000078c4] .ppc_clone+0x8/0xc Fix is the same way that mm/memory.c copy_page_range does the lockdep annotation. Acked-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: NAdam Litke <agl@us.ibm.com> Acked-by: NNishanth Aravamudan <nacc@us.ibm.com> Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 29 4月, 2008 2 次提交
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由 Nishanth Aravamudan 提交于
Add __GFP_REPEAT to hugepage allocations. Do so to not necessitate userspace putting pressure on the VM by repeated echo's into /proc/sys/vm/nr_hugepages to grow the pool. With the previous patch to allow for large-order __GFP_REPEAT attempts to loop for a bit (as opposed to indefinitely), this increases the likelihood of getting hugepages when the system experiences (or recently experienced) load. Mel tested the patchset on an x86_32 laptop. With the patches, it was easier to use the proc interface to grow the hugepage pool. The following is the output of a script that grows the pool as much as possible running on 2.6.25-rc9. Allocating hugepages test ------------------------- Disabling OOM Killer for current test process Starting page count: 0 Attempt 1: 57 pages Progress made with 57 pages Attempt 2: 73 pages Progress made with 16 pages Attempt 3: 74 pages Progress made with 1 pages Attempt 4: 75 pages Progress made with 1 pages Attempt 5: 77 pages Progress made with 2 pages 77 pages was the most it allocated but it took 5 attempts from userspace to get it. With the 3 patches in this series applied, Allocating hugepages test ------------------------- Disabling OOM Killer for current test process Starting page count: 0 Attempt 1: 75 pages Progress made with 75 pages Attempt 2: 76 pages Progress made with 1 pages Attempt 3: 79 pages Progress made with 3 pages And 79 pages was the most it got. Your patches were able to allocate the bulk of possible pages on the first attempt. Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com> Cc: Andy Whitcroft <apw@shadowen.org> Tested-by: NMel Gorman <mel@csn.ul.ie> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Harvey Harrison 提交于
mm/hugetlb.c:207:11: warning: Using plain integer as NULL pointer Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 28 4月, 2008 9 次提交
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由 Gerald Schaefer 提交于
Huge ptes have a special type on s390 and cannot be handled with the standard pte functions in certain cases, e.g. because of a different location of the invalid bit. This patch adds some new architecture- specific functions to hugetlb common code, as a prerequisite for the s390 large page support. This won't affect other architectures in functionality, but I need to add some new dummy inline functions to the headers. Acked-by: NMartin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: NGerald Schaefer <gerald.schaefer@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Gerald Schaefer 提交于
A cow break on a hugetlbfs page with page_count > 1 will set a new pte with set_huge_pte_at(), w/o any tlb flush operation. The old pte will remain in the tlb and subsequent write access to the page will result in a page fault loop, for as long as it may take until the tlb is flushed from somewhere else. This patch introduces an architecture-specific huge_ptep_clear_flush() function, which is called before the the set_huge_pte_at() in hugetlb_cow(). ATTENTION: This is just a nop on all architectures for now, the s390 implementation will come with our large page patch later. Other architectures should define their own huge_ptep_clear_flush() if needed. Acked-by: NMartin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: NGerald Schaefer <gerald.schaefer@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Lee Schermerhorn 提交于
After further discussion with Christoph Lameter, it has become clear that my earlier attempts to clean up the mempolicy reference counting were a bit of overkill in some areas, resulting in superflous ref/unref in what are usually fast paths. In other areas, further inspection reveals that I botched the unref for interleave policies. A separate patch, suitable for upstream/stable trees, fixes up the known errors in the previous attempt to fix reference counting. This patch reworks the memory policy referencing counting and, one hopes, simplifies the code. Maybe I'll get it right this time. See the update to the numa_memory_policy.txt document for a discussion of memory policy reference counting that motivates this patch. Summary: Lookup of mempolicy, based on (vma, address) need only add a reference for shared policy, and we need only unref the policy when finished for shared policies. So, this patch backs out all of the unneeded extra reference counting added by my previous attempt. It then unrefs only shared policies when we're finished with them, using the mpol_cond_put() [conditional put] helper function introduced by this patch. Note that shmem_swapin() calls read_swap_cache_async() with a dummy vma containing just the policy. read_swap_cache_async() can call alloc_page_vma() multiple times, so we can't let alloc_page_vma() unref the shared policy in this case. To avoid this, we make a copy of any non-null shared policy and remove the MPOL_F_SHARED flag from the copy. This copy occurs before reading a page [or multiple pages] from swap, so the overhead should not be an issue here. I introduced a new static inline function "mpol_cond_copy()" to copy the shared policy to an on-stack policy and remove the flags that would require a conditional free. The current implementation of mpol_cond_copy() assumes that the struct mempolicy contains no pointers to dynamically allocated structures that must be duplicated or reference counted during copy. Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com> Cc: Christoph Lameter <clameter@sgi.com> Cc: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Andi Kleen <ak@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Lee Schermerhorn 提交于
This is a change that was requested some time ago by Mel Gorman. Makes sense to me, so here it is. Note: I retain the name "mpol_free_shared_policy()" because it actually does free the shared_policy, which is NOT a reference counted object. However, ... The mempolicy object[s] referenced by the shared_policy are reference counted, so mpol_put() is used to release the reference held by the shared_policy. The mempolicy might not be freed at this time, because some task attached to the shared object associated with the shared policy may be in the process of allocating a page based on the mempolicy. In that case, the task performing the allocation will hold a reference on the mempolicy, obtained via mpol_shared_policy_lookup(). The mempolicy will be freed when all tasks holding such a reference have called mpol_put() for the mempolicy. Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com> Cc: Christoph Lameter <clameter@sgi.com> Cc: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Andi Kleen <ak@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Adam Litke 提交于
Allocating huge pages directly from the buddy allocator is not guaranteed to succeed. Success depends on several factors (such as the amount of physical memory available and the level of fragmentation). With the addition of dynamic hugetlb pool resizing, allocations can occur much more frequently. For these reasons it is desirable to keep track of huge page allocation successes and failures. Add two new vmstat entries to track huge page allocations that succeed and fail. The presence of the two entries is contingent upon CONFIG_HUGETLB_PAGE being enabled. [akpm@linux-foundation.org: reduced ifdeffery] Signed-off-by: NAdam Litke <agl@us.ibm.com> Signed-off-by: NEric Munson <ebmunson@us.ibm.com> Tested-by: NMel Gorman <mel@csn.ul.ie> Reviewed-by: NAndy Whitcroft <apw@shadowen.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Adam Litke 提交于
To reduce hugetlb_lock acquisitions and releases when freeing excess surplus pages, scan the page list in two parts. First, transfer the needed pages to the hugetlb pool. Then drop the lock and free the remaining pages back to the buddy allocator. In the common case there are zero excess pages and no lock operations are required. Thanks Mel Gorman for this improvement. Signed-off-by: NAdam Litke <agl@us.ibm.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Andy Whitcroft <apw@shadowen.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Mel Gorman 提交于
The MPOL_BIND policy creates a zonelist that is used for allocations controlled by that mempolicy. As the per-node zonelist is already being filtered based on a zone id, this patch adds a version of __alloc_pages() that takes a nodemask for further filtering. This eliminates the need for MPOL_BIND to create a custom zonelist. A positive benefit of this is that allocations using MPOL_BIND now use the local node's distance-ordered zonelist instead of a custom node-id-ordered zonelist. I.e., pages will be allocated from the closest allowed node with available memory. [Lee.Schermerhorn@hp.com: Mempolicy: update stale documentation and comments] [Lee.Schermerhorn@hp.com: Mempolicy: make dequeue_huge_page_vma() obey MPOL_BIND nodemask] [Lee.Schermerhorn@hp.com: Mempolicy: make dequeue_huge_page_vma() obey MPOL_BIND nodemask rework] Signed-off-by: NMel Gorman <mel@csn.ul.ie> Acked-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Mel Gorman 提交于
Filtering zonelists requires very frequent use of zone_idx(). This is costly as it involves a lookup of another structure and a substraction operation. As the zone_idx is often required, it should be quickly accessible. The node idx could also be stored here if it was found that accessing zone->node is significant which may be the case on workloads where nodemasks are heavily used. This patch introduces a struct zoneref to store a zone pointer and a zone index. The zonelist then consists of an array of these struct zonerefs which are looked up as necessary. Helpers are given for accessing the zone index as well as the node index. [kamezawa.hiroyu@jp.fujitsu.com: Suggested struct zoneref instead of embedding information in pointers] [hugh@veritas.com: mm-have-zonelist: fix memcg ooms] [hugh@veritas.com: just return do_try_to_free_pages] [hugh@veritas.com: do_try_to_free_pages gfp_mask redundant] Signed-off-by: NMel Gorman <mel@csn.ul.ie> Acked-by: NChristoph Lameter <clameter@sgi.com> Acked-by: NDavid Rientjes <rientjes@google.com> Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <clameter@sgi.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: NHugh Dickins <hugh@veritas.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Mel Gorman 提交于
Currently a node has two sets of zonelists, one for each zone type in the system and a second set for GFP_THISNODE allocations. Based on the zones allowed by a gfp mask, one of these zonelists is selected. All of these zonelists consume memory and occupy cache lines. This patch replaces the multiple zonelists per-node with two zonelists. The first contains all populated zones in the system, ordered by distance, for fallback allocations when the target/preferred node has no free pages. The second contains all populated zones in the node suitable for GFP_THISNODE allocations. An iterator macro is introduced called for_each_zone_zonelist() that interates through each zone allowed by the GFP flags in the selected zonelist. Signed-off-by: NMel Gorman <mel@csn.ul.ie> Acked-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <clameter@sgi.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 27 3月, 2008 2 次提交
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由 Nishanth Aravamudan 提交于
Running the counters testcase from libhugetlbfs results in on 2.6.25-rc5 and 2.6.25-rc5-mm1: BUG: soft lockup - CPU#3 stuck for 61s! [counters:10531] NIP: c0000000000d1f3c LR: c0000000000d1f2c CTR: c0000000001b5088 REGS: c000005db12cb360 TRAP: 0901 Not tainted (2.6.25-rc5-autokern1) MSR: 8000000000009032 <EE,ME,IR,DR> CR: 48008448 XER: 20000000 TASK = c000005dbf3d6000[10531] 'counters' THREAD: c000005db12c8000 CPU: 3 GPR00: 0000000000000004 c000005db12cb5e0 c000000000879228 0000000000000004 GPR04: 0000000000000010 0000000000000000 0000000000200200 0000000000100100 GPR08: c0000000008aba10 000000000000ffff 0000000000000004 0000000000000000 GPR12: 0000000028000442 c000000000770080 NIP [c0000000000d1f3c] .return_unused_surplus_pages+0x84/0x18c LR [c0000000000d1f2c] .return_unused_surplus_pages+0x74/0x18c Call Trace: [c000005db12cb5e0] [c000005db12cb670] 0xc000005db12cb670 (unreliable) [c000005db12cb670] [c0000000000d24c4] .hugetlb_acct_memory+0x2e0/0x354 [c000005db12cb740] [c0000000001b5048] .truncate_hugepages+0x1d4/0x214 [c000005db12cb890] [c0000000001b50a4] .hugetlbfs_delete_inode+0x1c/0x3c [c000005db12cb920] [c000000000103fd8] .generic_delete_inode+0xf8/0x1c0 [c000005db12cb9b0] [c0000000001b5100] .hugetlbfs_drop_inode+0x3c/0x24c [c000005db12cba50] [c00000000010287c] .iput+0xdc/0xf8 [c000005db12cbad0] [c0000000000fee54] .dentry_iput+0x12c/0x194 [c000005db12cbb60] [c0000000000ff050] .d_kill+0x6c/0xa4 [c000005db12cbbf0] [c0000000000ffb74] .dput+0x18c/0x1b0 [c000005db12cbc70] [c0000000000e9e98] .__fput+0x1a4/0x1e8 [c000005db12cbd10] [c0000000000e61ec] .filp_close+0xb8/0xe0 [c000005db12cbda0] [c0000000000e62d0] .sys_close+0xbc/0x134 [c000005db12cbe30] [c00000000000872c] syscall_exit+0x0/0x40 Instruction dump: ebbe8038 38800010 e8bf0002 3bbd0008 7fa3eb78 38a50001 7ca507b4 4818df25 60000000 38800010 38a00000 7c601b78 <7fa3eb78> 2f800010 409d0008 38000010 This was tracked down to a potential livelock in return_unused_surplus_hugepages(). In the case where we have surplus pages on some node, but no free pages on the same node, we may never break out of the loop. To avoid this livelock, terminate the search if we iterate a number of times equal to the number of online nodes without freeing a page. Thanks to Andy Whitcroft and Adam Litke for helping with debugging and the patch. Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Nishanth Aravamudan 提交于
Currently we show the surplus hugetlb pool state in /proc/meminfo, but not in the per-node meminfo files, even though we track the information on a per-node basis. Printing it there can help track down dynamic pool bugs including the one in the follow-on patch. Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 11 3月, 2008 1 次提交
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由 Adam Litke 提交于
Free pages in the hugetlb pool are free and as such have a reference count of zero. Regular allocations into the pool from the buddy are "freed" into the pool which results in their page_count dropping to zero. However, surplus pages can be directly utilized by the caller without first being freed to the pool. Therefore, a call to put_page_testzero() is in order so that such a page will be handed to the caller with a correct count. This has not affected end users because the bad page count is reset before the page is handed off. However, under CONFIG_DEBUG_VM this triggers a BUG when the page count is validated. Thanks go to Mel for first spotting this issue and providing an initial fix. Signed-off-by: NAdam Litke <agl@us.ibm.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Andy Whitcroft <apw@shadowen.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 05 3月, 2008 2 次提交
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由 Nishanth Aravamudan 提交于
Adam Litke noticed that currently we grow the hugepage pool independent of any cpuset the running process may be in, but when shrinking the pool, the cpuset is checked. This leads to inconsistency when shrinking the pool in a restricted cpuset -- an administrator may have been able to grow the pool on a node restricted by a containing cpuset, but they cannot shrink it there. There are two options: either prevent growing of the pool outside of the cpuset or allow shrinking outside of the cpuset. >From previous discussions on linux-mm, /proc/sys/vm/nr_hugepages is an administrative interface that should not be restricted by cpusets. So allow shrinking the pool by removing pages from nodes outside of current's cpuset. Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com> Acked-by: NAdam Litke <agl@us.ibm.com> Cc: William Irwin <wli@holomorphy.com> Cc: Lee Schermerhorn <Lee.Schermerhonr@hp.com> Cc: Christoph Lameter <clameter@sgi.com> Cc: Paul Jackson <pj@sgi.com> Cc: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Adam Litke 提交于
A hugetlb reservation may be inadequately backed in the event of racing allocations and frees when utilizing surplus huge pages. Consider the following series of events in processes A and B: A) Allocates some surplus pages to satisfy a reservation B) Frees some huge pages A) A notices the extra free pages and drops hugetlb_lock to free some of its surplus pages back to the buddy allocator. B) Allocates some huge pages A) Reacquires hugetlb_lock and returns from gather_surplus_huge_pages() Avoid this by commiting the reservation after pages have been allocated but before dropping the lock to free excess pages. For parity, release the reservation in return_unused_surplus_pages(). This patch also corrects the cpuset_mems_nr() error path in hugetlb_acct_memory(). If the cpuset check fails, uncommit the reservation, but also be sure to return any surplus huge pages that may have been allocated to back the failed reservation. Thanks to Andy Whitcroft for discovering this. Signed-off-by: NAdam Litke <agl@us.ibm.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Andy Whitcroft <apw@shadowen.org> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Andy Whitcroft <apw@shadowen.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 24 2月, 2008 1 次提交
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由 Andy Whitcroft 提交于
When we free a page via free_huge_page and we detect that we are in surplus the page will be returned to the buddy. After this we no longer own the page. However at the end free_huge_page we clear out our mapping pointer from page private. Even where the page is not a surplus we free the page to the hugepage pool, drop the pool locks and then clear page private. In either case the page may have been reallocated. BAD. Make sure we clear out page private before we free the page. Signed-off-by: NAndy Whitcroft <apw@shadowen.org> Acked-by: NAdam Litke <agl@us.ibm.com> Cc: <stable@kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 14 2月, 2008 1 次提交
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由 Nishanth Aravamudan 提交于
proc_doulongvec_minmax() calls copy_to_user()/copy_from_user(), so we can't hold hugetlb_lock over the call. Use a dummy variable to store the sysctl result, like in hugetlb_sysctl_handler(), then grab the lock to update nr_overcommit_huge_pages. Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com> Reported-by: NMiles Lane <miles.lane@gmail.com> Cc: Adam Litke <agl@us.ibm.com> Cc: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 09 2月, 2008 1 次提交
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由 Nishanth Aravamudan 提交于
When I replaced hugetlb_dynamic_pool with nr_overcommit_hugepages I used proc_doulongvec_minmax() directly. However, hugetlb.c's locking rules require that all counter modifications occur under the hugetlb_lock. Add a callback into the hugetlb code similar to the one for nr_hugepages. Grab the lock around the manipulation of nr_overcommit_hugepages in proc_doulongvec_minmax(). Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com> Acked-by: NAdam Litke <agl@us.ibm.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: <stable@kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 06 2月, 2008 1 次提交
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由 Nick Piggin 提交于
After running SetPageUptodate, preceeding stores to the page contents to actually bring it uptodate may not be ordered with the store to set the page uptodate. Therefore, another CPU which checks PageUptodate is true, then reads the page contents can get stale data. Fix this by having an smp_wmb before SetPageUptodate, and smp_rmb after PageUptodate. Many places that test PageUptodate, do so with the page locked, and this would be enough to ensure memory ordering in those places if SetPageUptodate were only called while the page is locked. Unfortunately that is not always the case for some filesystems, but it could be an idea for the future. Also bring the handling of anonymous page uptodateness in line with that of file backed page management, by marking anon pages as uptodate when they _are_ uptodate, rather than when our implementation requires that they be marked as such. Doing allows us to get rid of the smp_wmb's in the page copying functions, which were especially added for anonymous pages for an analogous memory ordering problem. Both file and anonymous pages are handled with the same barriers. FAQ: Q. Why not do this in flush_dcache_page? A. Firstly, flush_dcache_page handles only one side (the smb side) of the ordering protocol; we'd still need smp_rmb somewhere. Secondly, hiding away memory barriers in a completely unrelated function is nasty; at least in the PageUptodate macros, they are located together with (half) the operations involved in the ordering. Thirdly, the smp_wmb is only required when first bringing the page uptodate, wheras flush_dcache_page should be called each time it is written to through the kernel mapping. It is logically the wrong place to put it. Q. Why does this increase my text size / reduce my performance / etc. A. Because it is adding the necessary instructions to eliminate the data-race. Q. Can it be improved? A. Yes, eg. if you were to create a rule that all SetPageUptodate operations run under the page lock, we could avoid the smp_rmb places where PageUptodate is queried under the page lock. Requires audit of all filesystems and at least some would need reworking. That's great you're interested, I'm eagerly awaiting your patches. Signed-off-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 25 1月, 2008 1 次提交
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由 Larry Woodman 提交于
The shared page table code for hugetlb memory on x86 and x86_64 is causing a leak. When a user of hugepages exits using this code the system leaks some of the hugepages. ------------------------------------------------------- Part of /proc/meminfo just before database startup: HugePages_Total: 5500 HugePages_Free: 5500 HugePages_Rsvd: 0 Hugepagesize: 2048 kB Just before shutdown: HugePages_Total: 5500 HugePages_Free: 4475 HugePages_Rsvd: 0 Hugepagesize: 2048 kB After shutdown: HugePages_Total: 5500 HugePages_Free: 4988 HugePages_Rsvd: 0 Hugepagesize: 2048 kB ---------------------------------------------------------- The problem occurs durring a fork, in copy_hugetlb_page_range(). It locates the dst_pte using huge_pte_alloc(). Since huge_pte_alloc() calls huge_pmd_share() it will share the pmd page if can, yet the main loop in copy_hugetlb_page_range() does a get_page() on every hugepage. This is a violation of the shared hugepmd pagetable protocol and creates additional referenced to the hugepages causing a leak when the unmap of the VMA occurs. We can skip the entire replication of the ptes when the hugepage pagetables are shared. The attached patch skips copying the ptes and the get_page() calls if the hugetlbpage pagetable is shared. [akpm@linux-foundation.org: coding-style cleanups] Signed-off-by: NLarry Woodman <lwoodman@redhat.com> Signed-off-by: NAdam Litke <agl@us.ibm.com> Cc: Badari Pulavarty <pbadari@us.ibm.com> Cc: Ken Chen <kenchen@google.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: William Lee Irwin III <wli@holomorphy.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 15 1月, 2008 1 次提交
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由 Ken Chen 提交于
In the error path of both shared and private hugetlb page allocation, the file system quota is never undone, leading to fs quota leak. Fix them up. [akpm@linux-foundation.org: cleanup, micro-optimise] Signed-off-by: NKen Chen <kenchen@google.com> Acked-by: NAdam Litke <agl@us.ibm.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: William Lee Irwin III <wli@holomorphy.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 18 12月, 2007 2 次提交
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由 Nishanth Aravamudan 提交于
This reverts commit 54f9f80d ("hugetlb: Add hugetlb_dynamic_pool sysctl") Given the new sysctl nr_overcommit_hugepages, the boolean dynamic pool sysctl is not needed, as its semantics can be expressed by 0 in the overcommit sysctl (no dynamic pool) and non-0 in the overcommit sysctl (pool enabled). (Needed in 2.6.24 since it reverts a post-2.6.23 userspace-visible change) Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com> Acked-by: NAdam Litke <agl@us.ibm.com> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Nishanth Aravamudan 提交于
hugetlb: introduce nr_overcommit_hugepages sysctl While examining the code to support /proc/sys/vm/hugetlb_dynamic_pool, I became convinced that having a boolean sysctl was insufficient: 1) To support per-node control of hugepages, I have previously submitted patches to add a sysfs attribute related to nr_hugepages. However, with a boolean global value and per-mount quota enforcement constraining the dynamic pool, adding corresponding control of the dynamic pool on a per-node basis seems inconsistent to me. 2) Administration of the hugetlb dynamic pool with multiple hugetlbfs mount points is, arguably, more arduous than it needs to be. Each quota would need to be set separately, and the sum would need to be monitored. To ease the administration, and to help make the way for per-node control of the static & dynamic hugepage pool, I added a separate sysctl, nr_overcommit_hugepages. This value serves as a high watermark for the overall hugepage pool, while nr_hugepages serves as a low watermark. The boolean sysctl can then be removed, as the condition nr_overcommit_hugepages > 0 indicates the same administrative setting as hugetlb_dynamic_pool == 1 Quotas still serve as local enforcement of the size of the pool on a per-mount basis. A few caveats: 1) There is a race whereby the global surplus huge page counter is incremented before a hugepage has allocated. Another process could then try grow the pool, and fail to convert a surplus huge page to a normal huge page and instead allocate a fresh huge page. I believe this is benign, as no memory is leaked (the actual pages are still tracked correctly) and the counters won't go out of sync. 2) Shrinking the static pool while a surplus is in effect will allow the number of surplus huge pages to exceed the overcommit value. As long as this condition holds, however, no more surplus huge pages will be allowed on the system until one of the two sysctls are increased sufficiently, or the surplus huge pages go out of use and are freed. Successfully tested on x86_64 with the current libhugetlbfs snapshot, modified to use the new sysctl. Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com> Acked-by: NAdam Litke <agl@us.ibm.com> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 11 12月, 2007 1 次提交
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由 Adam Litke 提交于
The follow_hugetlb_page() fix I posted (merged as git commit 5b23dbe8) missed one case. If the pte is present, but not writable and write access is requested by the caller to get_user_pages(), the code will do the wrong thing. Rather than calling hugetlb_fault to make the pte writable, it notes the presence of the pte and continues. This simple one-liner makes sure we also fault on the pte for this case. Please apply. Signed-off-by: NAdam Litke <agl@us.ibm.com> Acked-by: NDave Kleikamp <shaggy@us.ibm.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 15 11月, 2007 1 次提交
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由 Ken Chen 提交于
For administrative purpose, we want to query actual block usage for hugetlbfs file via fstat. Currently, hugetlbfs always return 0. Fix that up since kernel already has all the information to track it properly. Signed-off-by: NKen Chen <kenchen@google.com> Acked-by: NAdam Litke <agl@us.ibm.com> Cc: Badari Pulavarty <pbadari@us.ibm.com> Cc: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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