hugetlb: fix pool shrinking while in restricted cpuset (348e1e04) · Commits · 戴 / test

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:

Nishanth Aravamudan <nacc@us.ibm.com> Acked-by:

Adam 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:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/hugetlb.c

+22 −4

Original line number	Diff line number	Diff line
		@@ -71,7 +71,25 @@ static void enqueue_huge_page(struct page *page)
		free_huge_pages_node[nid]++;
		}

		static struct page dequeue_huge_page(struct vm_area_struct vma,
		static struct page *dequeue_huge_page(void)
		{
		int nid;
		struct page *page = NULL;

		for (nid = 0; nid < MAX_NUMNODES; ++nid) {
		if (!list_empty(&hugepage_freelists[nid])) {
		page = list_entry(hugepage_freelists[nid].next,
		struct page, lru);
		list_del(&page->lru);
		free_huge_pages--;
		free_huge_pages_node[nid]--;
		break;
		}
		}
		return page;
		}

		static struct page dequeue_huge_page_vma(struct vm_area_struct vma,
		unsigned long address)
		{
		int nid;
		@@ -410,7 +428,7 @@ static struct page alloc_huge_page_shared(struct vm_area_struct vma,
		struct page *page;

		spin_lock(&hugetlb_lock);
		page = dequeue_huge_page(vma, addr);
		page = dequeue_huge_page_vma(vma, addr);
		spin_unlock(&hugetlb_lock);
		return page ? page : ERR_PTR(-VM_FAULT_OOM);
		}
		@@ -425,7 +443,7 @@ static struct page alloc_huge_page_private(struct vm_area_struct vma,

		spin_lock(&hugetlb_lock);
		if (free_huge_pages > resv_huge_pages)
		page = dequeue_huge_page(vma, addr);
		page = dequeue_huge_page_vma(vma, addr);
		spin_unlock(&hugetlb_lock);
		if (!page) {
		page = alloc_buddy_huge_page(vma, addr);
		@@ -578,7 +596,7 @@ static unsigned long set_max_huge_pages(unsigned long count)
		min_count = max(count, min_count);
		try_to_free_low(min_count);
		while (min_count < persistent_huge_pages) {
		struct page *page = dequeue_huge_page(NULL, 0);
		struct page *page = dequeue_huge_page();
		if (!page)
		break;
		update_and_free_page(page);

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