From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: miklos@szeredi.hu, akpm@linux-foundation.org, neilb@suse.de,
dgc@sgi.com, tomoki.sekiyama.qu@hitachi.com,
a.p.zijlstra@chello.nl, nikita@clusterfs.com,
trond.myklebust@fys.uio.no, yingchao.zhou@gmail.com,
richard@rsk.demon.co.uk, torvalds@linux-foundation.org,
Hugh Dickins <hugh@veritas.com>
Subject: [PATCH 03/23] lib: percpu_counter_sub
Date: Tue, 11 Sep 2007 21:53:53 +0200 [thread overview]
Message-ID: <20070911200012.216056000@chello.nl> (raw)
In-Reply-To: <20070911195350.825778000@chello.nl>
[-- Attachment #1: percpu_counter_sub.patch --]
[-- Type: text/plain, Size: 3065 bytes --]
Hugh spotted that some code does:
percpu_counter_add(&counter, -unsignedlong)
which, when the amount argument is of type s32, sort-of works thanks to
two's-complement. However when we'd change the type to s64 this breaks on 32bit
machines, because the promotion rules zero extend the unsigned number.
Provide percpu_counter_sub() to hide the s64 cast. That is:
percpu_counter_sub(&counter, foo)
is equal to:
percpu_counter_add(&counter, -(s64)foo);
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Hugh Dickins <hugh@veritas.com>
---
fs/ext2/balloc.c | 2 +-
fs/ext3/balloc.c | 2 +-
fs/ext4/balloc.c | 2 +-
include/linux/percpu_counter.h | 5 +++++
4 files changed, 8 insertions(+), 3 deletions(-)
Index: linux-2.6/fs/ext2/balloc.c
===================================================================
--- linux-2.6.orig/fs/ext2/balloc.c
+++ linux-2.6/fs/ext2/balloc.c
@@ -1367,7 +1367,7 @@ allocated:
}
group_adjust_blocks(sb, group_no, gdp, gdp_bh, -num);
- percpu_counter_add(&sbi->s_freeblocks_counter, -num);
+ percpu_counter_sub(&sbi->s_freeblocks_counter, num);
mark_buffer_dirty(bitmap_bh);
if (sb->s_flags & MS_SYNCHRONOUS)
Index: linux-2.6/fs/ext3/balloc.c
===================================================================
--- linux-2.6.orig/fs/ext3/balloc.c
+++ linux-2.6/fs/ext3/balloc.c
@@ -1672,7 +1672,7 @@ allocated:
gdp->bg_free_blocks_count =
cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count)-num);
spin_unlock(sb_bgl_lock(sbi, group_no));
- percpu_counter_add(&sbi->s_freeblocks_counter, -num);
+ percpu_counter_sub(&sbi->s_freeblocks_counter, num);
BUFFER_TRACE(gdp_bh, "journal_dirty_metadata for group descriptor");
err = ext3_journal_dirty_metadata(handle, gdp_bh);
Index: linux-2.6/fs/ext4/balloc.c
===================================================================
--- linux-2.6.orig/fs/ext4/balloc.c
+++ linux-2.6/fs/ext4/balloc.c
@@ -1697,7 +1697,7 @@ allocated:
gdp->bg_free_blocks_count =
cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count)-num);
spin_unlock(sb_bgl_lock(sbi, group_no));
- percpu_counter_add(&sbi->s_freeblocks_counter, -num);
+ percpu_counter_sub(&sbi->s_freeblocks_counter, num);
BUFFER_TRACE(gdp_bh, "journal_dirty_metadata for group descriptor");
err = ext4_journal_dirty_metadata(handle, gdp_bh);
Index: linux-2.6/include/linux/percpu_counter.h
===================================================================
--- linux-2.6.orig/include/linux/percpu_counter.h
+++ linux-2.6/include/linux/percpu_counter.h
@@ -105,4 +105,9 @@ static inline void percpu_counter_dec(st
percpu_counter_add(fbc, -1);
}
+static inline void percpu_counter_sub(struct percpu_counter *fbc, s64 amount)
+{
+ percpu_counter_add(fbc, -amount);
+}
+
#endif /* _LINUX_PERCPU_COUNTER_H */
--
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next prev parent reply other threads:[~2007-09-11 19:53 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-11 19:53 [PATCH 00/23] per device dirty throttling -v10 Peter Zijlstra
2007-09-11 19:53 ` [PATCH 01/23] nfs: remove congestion_end() Peter Zijlstra
2007-09-11 19:53 ` [PATCH 02/23] lib: percpu_counter_add Peter Zijlstra
2007-09-11 19:53 ` Peter Zijlstra [this message]
2007-09-11 19:53 ` [PATCH 04/23] lib: percpu_counter variable batch Peter Zijlstra
2007-09-11 19:53 ` [PATCH 05/23] lib: make percpu_counter_add take s64 Peter Zijlstra
2007-09-11 19:53 ` [PATCH 06/23] lib: percpu_counter_set Peter Zijlstra
2007-09-11 19:53 ` [PATCH 07/23] lib: percpu_counter_sum_positive Peter Zijlstra
2007-09-11 19:53 ` [PATCH 08/23] lib: percpu_count_sum() Peter Zijlstra
2007-09-11 19:53 ` [PATCH 09/23] lib: percpu_counter_init error handling Peter Zijlstra
2007-09-11 19:54 ` [PATCH 10/23] lib: percpu_counter_init_irq Peter Zijlstra
2007-09-11 19:54 ` [PATCH 11/23] mm: bdi init hooks Peter Zijlstra
2007-09-11 19:54 ` [PATCH 12/23] containers: " Peter Zijlstra
2007-09-11 19:54 ` [PATCH 13/23] mtd: " Peter Zijlstra
2007-09-11 19:54 ` [PATCH 14/23] mtd: clean up the backing_dev_info usage Peter Zijlstra
2007-09-11 19:54 ` [PATCH 15/23] mtd: give mtdconcat devices their own backing_dev_info Peter Zijlstra
2007-09-11 19:54 ` [PATCH 16/23] mm: scalable bdi statistics counters Peter Zijlstra
2007-09-11 19:54 ` [PATCH 17/23] mm: count reclaimable pages per BDI Peter Zijlstra
2007-09-11 19:54 ` [PATCH 18/23] mm: count writeback " Peter Zijlstra
2007-09-11 19:54 ` [PATCH 19/23] mm: expose BDI statistics in sysfs Peter Zijlstra
2007-09-11 19:54 ` [PATCH 20/23] lib: floating proportions Peter Zijlstra
2007-09-11 19:54 ` [PATCH 21/23] mm: per device dirty threshold Peter Zijlstra
2007-09-12 2:36 ` John Stoffel
2007-09-12 8:45 ` Peter Zijlstra
2007-09-11 19:54 ` [PATCH 22/23] mm: dirty balancing for tasks Peter Zijlstra
2007-09-11 19:54 ` [PATCH 23/23] debug: sysfs files for the current ratio/size/total Peter Zijlstra
2007-09-12 2:31 ` [PATCH 00/23] per device dirty throttling -v10 John Stoffel
2007-09-12 9:00 ` Peter Zijlstra
-- strict thread matches above, loose matches on Subject: below --
2007-08-16 7:45 [PATCH 00/23] per device dirty throttling -v9 Peter Zijlstra
2007-08-16 7:45 ` [PATCH 03/23] lib: percpu_counter_sub Peter Zijlstra
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