From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: "Theodore Ts'o" <tytso@mit.edu>
Cc: linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org,
Mingming Cao <cmm@us.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 01/42] percpu counter: clean up percpu_counter_sum_and_set()
Date: Thu, 09 Oct 2008 10:52:52 +0200 [thread overview]
Message-ID: <1223542372.7382.30.camel@lappy.programming.kicks-ass.net> (raw)
In-Reply-To: <1223525160-9887-2-git-send-email-tytso@mit.edu>
On Thu, 2008-10-09 at 00:05 -0400, Theodore Ts'o wrote:
> From: Mingming Cao <cmm@us.ibm.com>
>
> percpu_counter_sum_and_set() and percpu_counter_sum() is the same except
> the former updates the global counter after accounting. Since we are
> taking the fbc->lock to calculate the precise value of the counter in
> percpu_counter_sum() anyway, it should simply set fbc->count too, as the
> percpu_counter_sum_and_set() does.
>
> This patch merge these two interfaces into one.
I totally missed the patch introducing this _and_set() horror, but this
does look like a good cleanup.
Thanks Mingming!
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Signed-off-by: Mingming Cao <cmm@us.ibm.com>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Cc: <linux-ext4@vger.kernel.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
> ---
> fs/ext4/balloc.c | 2 +-
> include/linux/percpu_counter.h | 12 +++---------
> lib/percpu_counter.c | 8 +++-----
> 3 files changed, 7 insertions(+), 15 deletions(-)
>
> diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
> index e9fa960..00a94d5 100644
> --- a/fs/ext4/balloc.c
> +++ b/fs/ext4/balloc.c
> @@ -1624,7 +1624,7 @@ ext4_fsblk_t ext4_has_free_blocks(struct ext4_sb_info *sbi,
> #ifdef CONFIG_SMP
> if (free_blocks - root_blocks < FBC_BATCH)
> free_blocks =
> - percpu_counter_sum_and_set(&sbi->s_freeblocks_counter);
> + percpu_counter_sum(&sbi->s_freeblocks_counter);
> #endif
> if (free_blocks <= root_blocks)
> /* we don't have free space */
> diff --git a/include/linux/percpu_counter.h b/include/linux/percpu_counter.h
> index 2083888..9007ccd 100644
> --- a/include/linux/percpu_counter.h
> +++ b/include/linux/percpu_counter.h
> @@ -35,7 +35,7 @@ int percpu_counter_init_irq(struct percpu_counter *fbc, s64 amount);
> void percpu_counter_destroy(struct percpu_counter *fbc);
> void percpu_counter_set(struct percpu_counter *fbc, s64 amount);
> void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch);
> -s64 __percpu_counter_sum(struct percpu_counter *fbc, int set);
> +s64 __percpu_counter_sum(struct percpu_counter *fbc);
>
> static inline void percpu_counter_add(struct percpu_counter *fbc, s64 amount)
> {
> @@ -44,19 +44,13 @@ static inline void percpu_counter_add(struct percpu_counter *fbc, s64 amount)
>
> static inline s64 percpu_counter_sum_positive(struct percpu_counter *fbc)
> {
> - s64 ret = __percpu_counter_sum(fbc, 0);
> + s64 ret = __percpu_counter_sum(fbc);
> return ret < 0 ? 0 : ret;
> }
>
> -static inline s64 percpu_counter_sum_and_set(struct percpu_counter *fbc)
> -{
> - return __percpu_counter_sum(fbc, 1);
> -}
> -
> -
> static inline s64 percpu_counter_sum(struct percpu_counter *fbc)
> {
> - return __percpu_counter_sum(fbc, 0);
> + return __percpu_counter_sum(fbc);
> }
>
> static inline s64 percpu_counter_read(struct percpu_counter *fbc)
> diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
> index 4a8ba4b..a866389 100644
> --- a/lib/percpu_counter.c
> +++ b/lib/percpu_counter.c
> @@ -52,7 +52,7 @@ EXPORT_SYMBOL(__percpu_counter_add);
> * Add up all the per-cpu counts, return the result. This is a more accurate
> * but much slower version of percpu_counter_read_positive()
> */
> -s64 __percpu_counter_sum(struct percpu_counter *fbc, int set)
> +s64 __percpu_counter_sum(struct percpu_counter *fbc)
> {
> s64 ret;
> int cpu;
> @@ -62,11 +62,9 @@ s64 __percpu_counter_sum(struct percpu_counter *fbc, int set)
> for_each_online_cpu(cpu) {
> s32 *pcount = per_cpu_ptr(fbc->counters, cpu);
> ret += *pcount;
> - if (set)
> - *pcount = 0;
> + *pcount = 0;
> }
> - if (set)
> - fbc->count = ret;
> + fbc->count = ret;
>
> spin_unlock(&fbc->lock);
> return ret;
next prev parent reply other threads:[~2008-10-09 8:54 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-09 4:05 [PATCH 0/42] Ext4 patches queued up for the 2.6.28 merge window Theodore Ts'o
2008-10-09 4:05 ` [PATCH 01/42] percpu counter: clean up percpu_counter_sum_and_set() Theodore Ts'o
2008-10-09 4:05 ` [PATCH 02/42] ext4: Add printk priority levels to clean up checkpatch warnings Theodore Ts'o
2008-10-09 4:05 ` [PATCH 03/42] ext4: Fix long long " Theodore Ts'o
2008-10-09 4:05 ` [PATCH 04/42] ext4: Fix whitespace checkpatch warnings/errors Theodore Ts'o
2008-10-09 4:05 ` [PATCH 05/42] ext4: invalidate pages if delalloc block allocation fails Theodore Ts'o
2008-10-09 4:05 ` [PATCH 06/42] ext4: Make sure all the block allocation paths reserve blocks Theodore Ts'o
2008-10-09 4:05 ` [PATCH 07/42] ext4: Retry block reservation Theodore Ts'o
2008-10-09 4:05 ` [PATCH 08/42] ext4: Add percpu dirty block accounting Theodore Ts'o
2008-10-09 4:05 ` [PATCH 09/42] ext4: Switch to non delalloc mode when we are low on free blocks count Theodore Ts'o
2008-10-09 4:05 ` [PATCH 10/42] ext4: Signed arithmetic fix Theodore Ts'o
2008-10-09 4:05 ` [PATCH 11/42] ext4: Fix ext4 nomballoc allocator for ENOSPC Theodore Ts'o
2008-10-09 4:05 ` [PATCH 12/42] ext4: Don't add the inode to journal handle until after the block is allocated Theodore Ts'o
2008-10-09 4:05 ` [PATCH 13/42] ext4: Retry block allocation if we have free blocks left Theodore Ts'o
2008-10-09 4:05 ` [PATCH 14/42] ext4: truncate block allocated on a failed ext4_write_begin Theodore Ts'o
2008-10-09 4:05 ` [PATCH 15/42] ext4: Properly update i_disksize Theodore Ts'o
2008-10-09 4:05 ` [PATCH 16/42] ext4: Avoid printk floods in the face of directory corruption Theodore Ts'o
2008-10-09 4:05 ` [PATCH 17/42] Update flex_bg free blocks and free inodes counters when resizing Theodore Ts'o
2008-10-09 4:05 ` [PATCH 18/42] ext4: fix #11321: create /proc/ext4/*/stats more carefully Theodore Ts'o
2008-10-09 4:05 ` [PATCH 19/42] jbd2: clean up how the journal device name is printed Theodore Ts'o
2008-10-09 4:05 ` [PATCH 20/42] ext4: add missing unlock in ext4_check_descriptors() on error path Theodore Ts'o
2008-10-09 4:05 ` [PATCH 21/42] ext4: elevate write count for migrate ioctl Theodore Ts'o
2008-10-09 4:05 ` [PATCH 22/42] ext4: hook the ext3 migration interface to the EXT4_IOC_SETFLAGS ioctl Theodore Ts'o
2008-10-09 4:05 ` [PATCH 23/42] ext4: Renumber EXT4_IOC_MIGRATE Theodore Ts'o
2008-10-09 4:05 ` [PATCH 24/42] ext4: use percpu data structures for lg_prealloc_list Theodore Ts'o
2008-10-09 4:05 ` [PATCH 25/42] ext4/jbd2: Avoid WARN() messages when failing to write to the superblock Theodore Ts'o
2008-10-09 4:05 ` [PATCH 26/42] ext4: Don't use 'struct dentry' for internal lookups Theodore Ts'o
2008-10-09 4:05 ` [PATCH 27/42] ext4: move /proc setup and teardown out of mballoc.c Theodore Ts'o
2008-10-09 4:05 ` [PATCH 28/42] ext4: Combine proc file handling into a single set of functions Theodore Ts'o
2008-10-09 4:05 ` [PATCH 29/42] ext4: Use readahead when reading an inode from the inode table Theodore Ts'o
2008-10-09 4:05 ` [PATCH 30/42] ext4: Remove old legacy block allocator Theodore Ts'o
2008-10-09 4:05 ` [PATCH 31/42] ext4: fix initialization of UNINIT bitmap blocks Theodore Ts'o
2008-10-09 4:05 ` [PATCH 32/42] jbd2: abort instead of waiting for nonexistent transaction Theodore Ts'o
2008-10-09 4:05 ` [PATCH 33/42] ext4: Add debugging markers that can be used by systemtap Theodore Ts'o
2008-10-09 4:05 ` [PATCH 34/42] jbd2: Fix buffer head leak when writing the commit block Theodore Ts'o
2008-10-09 4:05 ` [PATCH 35/42] ext4: fix xattr deadlock Theodore Ts'o
2008-10-09 4:05 ` [PATCH 36/42] vfs: vfs-level fiemap interface Theodore Ts'o
2008-10-09 4:05 ` [PATCH 37/42] ocfs2: fiemap support Theodore Ts'o
2008-10-09 4:05 ` [PATCH 38/42] generic block based fiemap implementation Theodore Ts'o
2008-10-09 4:05 ` [PATCH 39/42] Hook ext4 to the vfs fiemap interface Theodore Ts'o
2008-10-09 4:05 ` [PATCH 40/42] Update ext4 MAINTAINERS file Theodore Ts'o
2008-10-09 4:05 ` [PATCH 41/42] ext4: Avoid double dirtying of super block in ext4_put_super() Theodore Ts'o
2008-10-09 4:06 ` [PATCH 42/42] ext4: Rename ext4dev to ext4 Theodore Ts'o
2008-10-11 22:04 ` Jeremy Fitzhardinge
2008-10-11 22:09 ` Eric Sandeen
2008-10-11 22:54 ` Jeremy Fitzhardinge
2008-10-11 22:58 ` Theodore Tso
2008-10-11 23:08 ` Grant Coady
2008-10-12 1:06 ` Eric Sandeen
2008-10-09 8:18 ` [PATCH 29/42] ext4: Use readahead when reading an inode from the inode table Aneesh Kumar K.V
2008-10-09 8:52 ` Peter Zijlstra [this message]
2008-10-09 16:52 ` [PATCH 01/42] percpu counter: clean up percpu_counter_sum_and_set() Theodore Tso
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1223542372.7382.30.camel@lappy.programming.kicks-ass.net \
--to=a.p.zijlstra@chello.nl \
--cc=akpm@linux-foundation.org \
--cc=cmm@us.ibm.com \
--cc=linux-ext4@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=tytso@mit.edu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
Powered by JetHome