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| author | Mel Gorman <mel@csn.ul.ie> | 2007-05-06 14:49:30 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-07 12:12:53 -0700 |
| commit | 3b1d92c56514987010bb0201b5c71aeb633fc4f8 (patch) | |
| tree | f31a72692c35eb27fc94590964ba389776c0439f /mm/page_alloc.c | |
| parent | 8da3430d8a7f885c2bf65121181d76c9d290a86e (diff) | |
| download | lwn-3b1d92c56514987010bb0201b5c71aeb633fc4f8.tar.gz lwn-3b1d92c56514987010bb0201b5c71aeb633fc4f8.zip | |
Do not disable interrupts when reading min_free_kbytes
The sysctl handler for min_free_kbytes calls setup_per_zone_pages_min() on
read or write. This function iterates through every zone and calls
spin_lock_irqsave() on the zone LRU lock. When reading min_free_kbytes,
this is a total waste of time that disables interrupts on the local
processor. It might even be noticable machines with large numbers of zones
if a process started constantly reading min_free_kbytes.
This patch only calls setup_per_zone_pages_min() only on write. Tested on
an x86 laptop and it did the right thing.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Christoph Lameter <clameter@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_alloc.c')
| -rw-r--r-- | mm/page_alloc.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index f564717d22f3..542fc088ff50 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3199,7 +3199,8 @@ int min_free_kbytes_sysctl_handler(ctl_table *table, int write, struct file *file, void __user *buffer, size_t *length, loff_t *ppos) { proc_dointvec(table, write, file, buffer, length, ppos); - setup_per_zone_pages_min(); + if (write) + setup_per_zone_pages_min(); return 0; } |