From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adam Litke Subject: [PATCH 3/5] hugetlb: Debit quota in alloc_huge_page Date: Tue, 30 Oct 2007 13:46:27 -0700 Message-Id: <20071030204627.16585.26983.stgit@kernel> In-Reply-To: <20071030204554.16585.80588.stgit@kernel> References: <20071030204554.16585.80588.stgit@kernel> Content-Type: text/plain; charset=utf-8; format=fixed Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@kvack.org, Ken Chen , Andy Whitcroft , Dave Hansen , Adam Litke List-ID: Now that quota is credited by free_huge_page(), calls to hugetlb_get_quota() seem out of place. The alloc/free API is unbalanced because we handle the hugetlb_put_quota() but expect the caller to open-code hugetlb_get_quota(). Move the get inside alloc_huge_page to clean up this disparity. This patch has been kept apart from the previous patch because of the somewhat dodgy ERR_PTR() use herein. Moving the quota logic means that alloc_huge_page() has two failure modes. Quota failure must result in a SIGBUS while a standard allocation failure is OOM. Unfortunately, ERR_PTR() doesn't like the small positive errnos we have in VM_FAULT_* so they must be negated before they are used. Does anyone take issue with the way I am using PTR_ERR. If so, what are your thoughts on how to clean this up (without needing an if,else if,else block at each alloc_huge_page() callsite)? Signed-off-by: Adam Litke STG: Please edit the description for patch "get-quota-on-alloc-V2" above. STG: Lines prefixed with "STG:" will be automatically removed. STG: Trailing empty lines will be automatically removed. STG: vi: set textwidth=75 filetype=diff nobackup: --- mm/hugetlb.c | 24 ++++++++++++------------ 1 files changed, 12 insertions(+), 12 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 0b09ef2..5eacee8 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -388,6 +388,10 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma, unsigned long addr) { struct page *page; + struct address_space *mapping = vma->vm_file->f_mapping; + + if (hugetlb_get_quota(mapping)) + return ERR_PTR(-VM_FAULT_SIGBUS); if (vma->vm_flags & VM_MAYSHARE) page = alloc_huge_page_shared(vma, addr); @@ -395,9 +399,10 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma, page = alloc_huge_page_private(vma, addr); if (page) { set_page_refcounted(page); - set_page_private(page, (unsigned long) vma->vm_file->f_mapping); - } - return page; + set_page_private(page, (unsigned long) mapping); + return page; + } else + return ERR_PTR(-VM_FAULT_OOM); } static int __init hugetlb_init(void) @@ -737,15 +742,13 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, set_huge_ptep_writable(vma, address, ptep); return 0; } - if (hugetlb_get_quota(vma->vm_file->f_mapping)) - return VM_FAULT_SIGBUS; page_cache_get(old_page); new_page = alloc_huge_page(vma, address); - if (!new_page) { + if (IS_ERR(new_page)) { page_cache_release(old_page); - return VM_FAULT_OOM; + return -PTR_ERR(new_page); } spin_unlock(&mm->page_table_lock); @@ -789,12 +792,9 @@ retry: size = i_size_read(mapping->host) >> HPAGE_SHIFT; if (idx >= size) goto out; - if (hugetlb_get_quota(mapping)) - goto out; page = alloc_huge_page(vma, address); - if (!page) { - hugetlb_put_quota(mapping); - ret = VM_FAULT_OOM; + if (IS_ERR(page)) { + ret = -PTR_ERR(page); goto out; } clear_huge_page(page, address); -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org