linux-kernel - [PATCH] fadvise: only initiate writeback for specified range with FADV

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 31 Oct 2011 11:16:59 -0500
From:	Shawn Bohrer <sbohrer@...advisors.com>
To:	linux-mm@...ck.org
Cc:	linux-kernel@...r.kernel.org,
	Shawn Bohrer <sbohrer@...advisors.com>
Subject: [PATCH] fadvise: only initiate writeback for specified range with FADV_DONTNEED

Previously POSIX_FADV_DONTNEED would start writeback for the entire file
when the bdi was not write congested.  This negatively impacts
performance if the file contians dirty pages outside of the requested
range.  This change uses __filemap_fdatawrite_range() to only initiate
writeback for the requested range.

Signed-off-by: Shawn Bohrer <sbohrer@...advisors.com>
---
 mm/fadvise.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/mm/fadvise.c b/mm/fadvise.c
index 8d723c9..469491e 100644
--- a/mm/fadvise.c
+++ b/mm/fadvise.c
@@ -117,7 +117,8 @@ SYSCALL_DEFINE(fadvise64_64)(int fd, loff_t offset, loff_t len, int advice)
 		break;
 	case POSIX_FADV_DONTNEED:
 		if (!bdi_write_congested(mapping->backing_dev_info))
-			filemap_flush(mapping);
+			__filemap_fdatawrite_range(mapping, offset, endbyte,
+						   WB_SYNC_NONE);
 
 		/* First and last FULL page! */
 		start_index = (offset+(PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT;
-- 
1.7.6



---------------------------------------------------------------
This email, along with any attachments, is confidential. If you 
believe you received this message in error, please contact the 
sender immediately and delete all copies of the message.  
Thank you.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/