| Message ID | 20250224012005.689549-1-wozizhi@huawei.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | ext4: Modify the comment about mb_optimize_scan | expand |
On 2025/2/24 9:20, Zizhi Wo wrote: > Commit 196e402adf2e ("ext4: improve cr 0 / cr 1 group scanning") introduces > the sysfs control interface "mb_max_linear_groups" to address the problem > that rotational devices performance degrades when the "mb_optimize_scan" > feature is enabled, which may result in distant block group allocation. > > However, the name of the interface was incorrect in the comment to the > ext4/mballoc.c file, and this patch fixes it, without further changes. > > Signed-off-by: Zizhi Wo <wozizhi@huawei.com> Looks good to me. Reviewed-by: Zhang Yi <yi.zhang@huawei.com> > --- > fs/ext4/mballoc.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c > index b25a27c86696..68b54afc78c7 100644 > --- a/fs/ext4/mballoc.c > +++ b/fs/ext4/mballoc.c > @@ -187,7 +187,7 @@ > * /sys/fs/ext4/<partition>/mb_min_to_scan > * /sys/fs/ext4/<partition>/mb_max_to_scan > * /sys/fs/ext4/<partition>/mb_order2_req > - * /sys/fs/ext4/<partition>/mb_linear_limit > + * /sys/fs/ext4/<partition>/mb_max_linear_groups > * > * The regular allocator uses buddy scan only if the request len is power of > * 2 blocks and the order of allocation is >= sbi->s_mb_order2_reqs. The > @@ -209,7 +209,7 @@ > * get traversed linearly. That may result in subsequent allocations being not > * close to each other. And so, the underlying device may get filled up in a > * non-linear fashion. While that may not matter on non-rotational devices, for > - * rotational devices that may result in higher seek times. "mb_linear_limit" > + * rotational devices that may result in higher seek times. "mb_max_linear_groups" > * tells mballoc how many groups mballoc should search linearly before > * performing consulting above data structures for more efficient lookups. For > * non rotational devices, this value defaults to 0 and for rotational devices
On Mon, Feb 24, 2025 at 09:20:05AM +0800, Zizhi Wo wrote: > Commit 196e402adf2e ("ext4: improve cr 0 / cr 1 group scanning") introduces > the sysfs control interface "mb_max_linear_groups" to address the problem > that rotational devices performance degrades when the "mb_optimize_scan" > feature is enabled, which may result in distant block group allocation. > > However, the name of the interface was incorrect in the comment to the > ext4/mballoc.c file, and this patch fixes it, without further changes. Looks good Zizhi, feel free to add: Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> IIRC the documentation above mballoc is a bit outdated and it might be a good idea to see if we can make more improvements there. Maybe something worth exploring Regards, ojaswin > > Signed-off-by: Zizhi Wo <wozizhi@huawei.com> > --- > fs/ext4/mballoc.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c > index b25a27c86696..68b54afc78c7 100644 > --- a/fs/ext4/mballoc.c > +++ b/fs/ext4/mballoc.c > @@ -187,7 +187,7 @@ > * /sys/fs/ext4/<partition>/mb_min_to_scan > * /sys/fs/ext4/<partition>/mb_max_to_scan > * /sys/fs/ext4/<partition>/mb_order2_req > - * /sys/fs/ext4/<partition>/mb_linear_limit > + * /sys/fs/ext4/<partition>/mb_max_linear_groups > * > * The regular allocator uses buddy scan only if the request len is power of > * 2 blocks and the order of allocation is >= sbi->s_mb_order2_reqs. The > @@ -209,7 +209,7 @@ > * get traversed linearly. That may result in subsequent allocations being not > * close to each other. And so, the underlying device may get filled up in a > * non-linear fashion. While that may not matter on non-rotational devices, for > - * rotational devices that may result in higher seek times. "mb_linear_limit" > + * rotational devices that may result in higher seek times. "mb_max_linear_groups" > * tells mballoc how many groups mballoc should search linearly before > * performing consulting above data structures for more efficient lookups. For > * non rotational devices, this value defaults to 0 and for rotational devices > -- > 2.39.2 >
On 2025/2/24 9:20, Zizhi Wo wrote: > Commit 196e402adf2e ("ext4: improve cr 0 / cr 1 group scanning") introduces > the sysfs control interface "mb_max_linear_groups" to address the problem > that rotational devices performance degrades when the "mb_optimize_scan" > feature is enabled, which may result in distant block group allocation. > > However, the name of the interface was incorrect in the comment to the > ext4/mballoc.c file, and this patch fixes it, without further changes. > > Signed-off-by: Zizhi Wo <wozizhi@huawei.com> Looks good. Reviewed-by: Baokun Li <libaokun1@huawei.com> > --- > fs/ext4/mballoc.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c > index b25a27c86696..68b54afc78c7 100644 > --- a/fs/ext4/mballoc.c > +++ b/fs/ext4/mballoc.c > @@ -187,7 +187,7 @@ > * /sys/fs/ext4/<partition>/mb_min_to_scan > * /sys/fs/ext4/<partition>/mb_max_to_scan > * /sys/fs/ext4/<partition>/mb_order2_req > - * /sys/fs/ext4/<partition>/mb_linear_limit > + * /sys/fs/ext4/<partition>/mb_max_linear_groups > * > * The regular allocator uses buddy scan only if the request len is power of > * 2 blocks and the order of allocation is >= sbi->s_mb_order2_reqs. The > @@ -209,7 +209,7 @@ > * get traversed linearly. That may result in subsequent allocations being not > * close to each other. And so, the underlying device may get filled up in a > * non-linear fashion. While that may not matter on non-rotational devices, for > - * rotational devices that may result in higher seek times. "mb_linear_limit" > + * rotational devices that may result in higher seek times. "mb_max_linear_groups" > * tells mballoc how many groups mballoc should search linearly before > * performing consulting above data structures for more efficient lookups. For > * non rotational devices, this value defaults to 0 and for rotational devices
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index b25a27c86696..68b54afc78c7 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -187,7 +187,7 @@ * /sys/fs/ext4/<partition>/mb_min_to_scan * /sys/fs/ext4/<partition>/mb_max_to_scan * /sys/fs/ext4/<partition>/mb_order2_req - * /sys/fs/ext4/<partition>/mb_linear_limit + * /sys/fs/ext4/<partition>/mb_max_linear_groups * * The regular allocator uses buddy scan only if the request len is power of * 2 blocks and the order of allocation is >= sbi->s_mb_order2_reqs. The @@ -209,7 +209,7 @@ * get traversed linearly. That may result in subsequent allocations being not * close to each other. And so, the underlying device may get filled up in a * non-linear fashion. While that may not matter on non-rotational devices, for - * rotational devices that may result in higher seek times. "mb_linear_limit" + * rotational devices that may result in higher seek times. "mb_max_linear_groups" * tells mballoc how many groups mballoc should search linearly before * performing consulting above data structures for more efficient lookups. For * non rotational devices, this value defaults to 0 and for rotational devices
Commit 196e402adf2e ("ext4: improve cr 0 / cr 1 group scanning") introduces the sysfs control interface "mb_max_linear_groups" to address the problem that rotational devices performance degrades when the "mb_optimize_scan" feature is enabled, which may result in distant block group allocation. However, the name of the interface was incorrect in the comment to the ext4/mballoc.c file, and this patch fixes it, without further changes. Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/ext4/mballoc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)