Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756103Ab1CBIig (ORCPT ); Wed, 2 Mar 2011 03:38:36 -0500 Received: from mail-yw0-f46.google.com ([209.85.213.46]:51025 "EHLO mail-yw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755903Ab1CBIid (ORCPT ); Wed, 2 Mar 2011 03:38:33 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=from:to:subject:date:message-id:x-mailer:in-reply-to:references; b=BGng6jx/ki54VNOWcySi4xZZNLjgJ/0qBSHepy7JEg+Bqf4QegABHsB98gdUu9M8/j Vg19vg1vIqPbanIUWOOLExIgM1k9JLG51n8dituvg+JkcIpR8+MbgWCH3M9QFDHj2t2N 4HnboDv9+aM4X8j4meWdGPri/AAqcJC3gxFqo= From: Liu Yuan To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, jaxboe@fusionio.com, akpm@linux-foundation.org, fengguang.wu@intel.com Subject: [RFC PATCH 4/5] mm: Add hit/miss accounting for Page Cache Date: Wed, 2 Mar 2011 16:38:09 +0800 Message-Id: <1299055090-23976-4-git-send-email-namei.unix@gmail.com> X-Mailer: git-send-email 1.7.0.4 In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3413 Lines: 116 From: Liu Yuan Hit/Miss accountings are request-centric: that is, single request would either cause one hit or one miss to be accounted for the very first time that kernel query the page cache. In some rare error conditions, kernel would re-query the page cache, but we donnot account for it and ignore it for simplicity. Signed-off-by: Liu Yuan --- mm/filemap.c | 26 ++++++++++++++++++++++---- 1 files changed, 22 insertions(+), 4 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index 83a45d3..5388b2a 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1009,10 +1009,15 @@ static void do_generic_file_read(struct file *filp, loff_t *ppos, pgoff_t end_index; loff_t isize; unsigned long nr, ret; + int retry_find = 0; cond_resched(); find_page: page = find_get_page(mapping, index); + if (likely(!retry_find) && page && PageUptodate(page)) + page_cache_acct_hit(inode->i_sb, READ); + else + page_cache_acct_missed(inode->i_sb, READ); if (!page) { page_cache_sync_readahead(mapping, ra, filp, @@ -1137,6 +1142,7 @@ readpage: if (unlikely(error)) { if (error == AOP_TRUNCATED_PAGE) { page_cache_release(page); + retry_find = 1; goto find_page; } goto readpage_error; @@ -1153,6 +1159,7 @@ readpage: */ unlock_page(page); page_cache_release(page); + retry_find = 1; goto find_page; } unlock_page(page); @@ -1185,8 +1192,10 @@ no_cached_page: index, GFP_KERNEL); if (error) { page_cache_release(page); - if (error == -EEXIST) + if (error == -EEXIST) { + retry_find = 1; goto find_page; + } desc->error = error; goto out; } @@ -1543,6 +1552,7 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) struct page *page; pgoff_t size; int ret = 0; + int rw = !!(vmf->flags & FAULT_FLAG_WRITE); size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; if (offset >= size) @@ -1552,6 +1562,10 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) * Do we have something in the page cache already? */ page = find_get_page(mapping, offset); + if (page && page->mapping && PageUptodate(page)) + page_cache_acct_hit(inode->i_sb, rw); + else + page_cache_acct_missed(inode->i_sb, rw); if (likely(page)) { /* * We found the page, so try async readahead before @@ -2227,20 +2241,24 @@ struct page *grab_cache_page_write_begin(struct address_space *mapping, gfp_notmask = __GFP_FS; repeat: page = find_lock_page(mapping, index); - if (page) + if (page) { + page_cache_acct_hit(mapping->host->i_sb, WRITE); return page; + } page = __page_cache_alloc(mapping_gfp_mask(mapping) & ~gfp_notmask); if (!page) - return NULL; + goto out; status = add_to_page_cache_lru(page, mapping, index, GFP_KERNEL & ~gfp_notmask); if (unlikely(status)) { page_cache_release(page); if (status == -EEXIST) goto repeat; - return NULL; + page = NULL; } +out: + page_cache_acct_missed(mapping->host->i_sb, WRITE); return page; } EXPORT_SYMBOL(grab_cache_page_write_begin); -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/