From 571640cad3fda6475da45d91cf86076f1f86bd9b Mon Sep 17 00:00:00 2001 From: Eric Sandeen Date: Mon, 26 May 2008 12:29:46 -0400 Subject: ext4: enable barriers by default I can't think of any valid reason for ext4 to not use barriers when they are available; I believe this is necessary for filesystem integrity in the face of a volatile write cache on storage. An administrator who trusts that the cache is sufficiently battery- backed (and power supplies are sufficiently redundant, etc...) can always turn it back off again. SuSE has carried such a patch for ext3 for quite some time now. Also document the mount option while we're at it. Signed-off-by: Eric Sandeen Signed-off-by: Mingming Cao Signed-off-by: "Theodore Ts'o" --- Documentation/filesystems/ext4.txt | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'Documentation/filesystems') diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt index 560f88dc709..0c5086db835 100644 --- a/Documentation/filesystems/ext4.txt +++ b/Documentation/filesystems/ext4.txt @@ -139,8 +139,16 @@ commit=nrsec (*) Ext4 can be told to sync all its data and metadata Setting it to very large values will improve performance. -barrier=1 This enables/disables barriers. barrier=0 disables - it, barrier=1 enables it. +barrier=<0|1(*)> This enables/disables the use of write barriers in + the jbd code. barrier=0 disables, barrier=1 enables. + This also requires an IO stack which can support + barriers, and if jbd gets an error on a barrier + write, it will disable again with a warning. + Write barriers enforce proper on-disk ordering + of journal commits, making volatile disk write caches + safe to use, at some performance penalty. If + your disks are battery-backed in one way or another, + disabling barriers may safely improve performance. orlov (*) This enables the new Orlov block allocator. It is enabled by default. -- cgit v1.2.3 From 45aec1ae72fc592f231e9e73ed9ed4d10cfbc0b5 Mon Sep 17 00:00:00 2001 From: "venkatesh.pallipadi@intel.com" Date: Tue, 18 Mar 2008 17:00:22 -0700 Subject: x86: PAT export resource_wc in pci sysfs For the ranges with IORESOURCE_PREFETCH, export a new resource_wc interface in pci /sysfs along with resource (which is uncached). Signed-off-by: Venkatesh Pallipadi Signed-off-by: Suresh Siddha Acked-by: Jesse Barnes Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- Documentation/filesystems/sysfs-pci.txt | 1 + 1 file changed, 1 insertion(+) (limited to 'Documentation/filesystems') diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt index 5daa2aaec2c..68ef48839c0 100644 --- a/Documentation/filesystems/sysfs-pci.txt +++ b/Documentation/filesystems/sysfs-pci.txt @@ -36,6 +36,7 @@ files, each with their own function. local_cpus nearby CPU mask (cpumask, ro) resource PCI resource host addresses (ascii, ro) resource0..N PCI resource N, if present (binary, mmap) + resource0_wc..N_wc PCI WC map resource N, if prefetchable (binary, mmap) rom PCI ROM resource, if present (binary, ro) subsystem_device PCI subsystem device (ascii, ro) subsystem_vendor PCI subsystem vendor (ascii, ro) -- cgit v1.2.3