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From: Wu Fengguang <fengguang.wu@intel.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Andi Kleen <andi@firstfloor.org>, Jan Kara <jack@suse.cz>,
	Wu Fengguang <fengguang.wu@intel.com>
Cc: Linux Memory Management List <linux-mm@kvack.org>,
	<linux-fsdevel@vger.kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH 3/9] readahead: tag mmap page fault call sites
Date: Fri, 27 Jan 2012 11:05:27 +0800	[thread overview]
Message-ID: <20120127031326.752229208@intel.com> (raw)
In-Reply-To: 20120127030524.854259561@intel.com

[-- Attachment #1: readahead-for-mmap --]
[-- Type: text/plain, Size: 2068 bytes --]

Introduce a bit field ra->for_mmap for tagging mmap reads.
The tag will be cleared immediate after submitting the IO.

Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
 include/linux/fs.h |    1 +
 mm/filemap.c       |    6 +++++-
 mm/readahead.c     |    1 +
 3 files changed, 7 insertions(+), 1 deletion(-)

--- linux-next.orig/include/linux/fs.h	2012-01-25 15:57:50.000000000 +0800
+++ linux-next/include/linux/fs.h	2012-01-25 15:57:51.000000000 +0800
@@ -954,6 +954,7 @@ struct file_ra_state {
 	unsigned int ra_pages;		/* Maximum readahead window */
 	u16 mmap_miss;			/* Cache miss stat for mmap accesses */
 	u8 pattern;			/* one of RA_PATTERN_* */
+	unsigned int for_mmap:1;	/* readahead for mmap accesses */
 
 	loff_t prev_pos;		/* Cache last read() position */
 };
--- linux-next.orig/mm/filemap.c	2012-01-25 15:57:50.000000000 +0800
+++ linux-next/mm/filemap.c	2012-01-25 15:57:51.000000000 +0800
@@ -1578,6 +1578,7 @@ static void do_sync_mmap_readahead(struc
 		return;
 
 	if (VM_SequentialReadHint(vma)) {
+		ra->for_mmap = 1;
 		page_cache_sync_readahead(mapping, ra, file, offset,
 					  ra->ra_pages);
 		return;
@@ -1597,6 +1598,7 @@ static void do_sync_mmap_readahead(struc
 	/*
 	 * mmap read-around
 	 */
+	ra->for_mmap = 1;
 	ra->pattern = RA_PATTERN_MMAP_AROUND;
 	ra_pages = max_sane_readahead(ra->ra_pages);
 	ra->start = max_t(long, 0, offset - ra_pages / 2);
@@ -1622,9 +1624,11 @@ static void do_async_mmap_readahead(stru
 		return;
 	if (ra->mmap_miss > 0)
 		ra->mmap_miss--;
-	if (PageReadahead(page))
+	if (PageReadahead(page)) {
+		ra->for_mmap = 1;
 		page_cache_async_readahead(mapping, ra, file,
 					   page, offset, ra->ra_pages);
+	}
 }
 
 /**
--- linux-next.orig/mm/readahead.c	2012-01-25 15:57:50.000000000 +0800
+++ linux-next/mm/readahead.c	2012-01-25 15:57:51.000000000 +0800
@@ -259,6 +259,7 @@ unsigned long ra_submit(struct file_ra_s
 	actual = __do_page_cache_readahead(mapping, filp,
 					ra->start, ra->size, ra->async_size);
 
+	ra->for_mmap = 0;
 	return actual;
 }
 



  parent reply	other threads:[~2012-01-27  3:41 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-27  3:05 [PATCH 0/9] readahead stats/tracing, backwards prefetching and more (v4) Wu Fengguang
2012-01-27  3:05 ` [PATCH 1/9] readahead: make context readahead more conservative Wu Fengguang
2012-01-27  3:05 ` [PATCH 2/9] readahead: record readahead patterns Wu Fengguang
2012-01-27  3:05 ` Wu Fengguang [this message]
2012-01-27  3:05 ` [PATCH 4/9] readahead: tag metadata call sites Wu Fengguang
2012-01-27  3:05 ` [PATCH 5/9] readahead: add vfs/readahead tracing event Wu Fengguang
2012-01-27  3:05 ` [PATCH 6/9] readahead: add /debug/readahead/stats Wu Fengguang
2012-01-27 16:21   ` Christoph Lameter
2012-01-27 20:15     ` Andrew Morton
2012-01-29  5:07       ` Wu Fengguang
2012-01-30  4:02       ` Dave Chinner
2012-01-27  3:05 ` [PATCH 7/9] readahead: basic support for backwards prefetching Wu Fengguang
2012-01-27  3:05 ` [PATCH 8/9] readahead: dont do start-of-file readahead after lseek() Wu Fengguang
2012-01-27  3:05 ` [PATCH 9/9] readahead: snap readahead request to EOF Wu Fengguang
2012-02-09  3:22 ` [PATCH 6/9 update changelog] readahead: add /debug/readahead/stats Wu Fengguang
2012-02-11  4:31 [PATCH 0/9] readahead stats/tracing, backwards prefetching and more (v5) Wu Fengguang
2012-02-11  4:31 ` [PATCH 3/9] readahead: tag mmap page fault call sites Wu Fengguang

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