Add a new function shrink_page_cache(), it will call do_try_to_free_pages()
to reclaim the page cache.
Signed-off-by: Xishi Qiu <qiuxishi@xxxxxxxxxx>
---
include/linux/swap.h | 2 ++
mm/page_alloc.c | 12 ++++++++++++
mm/vmscan.c | 24 ++++++++++++++++++++++++
3 files changed, 38 insertions(+), 0 deletions(-)
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 7e362d7..dcbe1a3 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -363,6 +363,8 @@ extern int cache_limit_ratio_sysctl_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *length, loff_t *ppos);
extern int cache_limit_mbytes_sysctl_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *length, loff_t *ppos);
+extern unsigned long page_cache_over_limit(void);
+extern void shrink_page_cache(gfp_t mask);
#ifdef CONFIG_NUMA
extern int zone_reclaim_mode;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a9cc034..00707ef 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5829,6 +5829,18 @@ int cache_limit_mbytes_sysctl_handler(struct ctl_table *table, int write,
return 0;
}
+unsigned long page_cache_over_limit(void)
+{
+ unsigned long lru_file, limit;
+
+ limit = vm_cache_limit_mbytes * ((1024 * 1024UL) / PAGE_SIZE);
+ lru_file = global_page_state(NR_ACTIVE_FILE)
+ + global_page_state(NR_INACTIVE_FILE);
+ if (lru_file > limit)
+ return lru_file - limit;
+ return 0;
+}
+
#ifdef CONFIG_NUMA
int sysctl_min_unmapped_ratio_sysctl_handler(ctl_table *table, int write,
void __user *buffer, size_t *length, loff_t *ppos)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 37ea902..ad01ff4 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3389,6 +3389,30 @@ static void shrink_page_cache_init(void)
vm_cache_limit_mbytes_max = totalram_pages;
}
+static unsigned long __shrink_page_cache(gfp_t mask)
+{
+ struct scan_control sc = {
+ .gfp_mask = (mask = memalloc_noio_flags(mask)),
+ .may_writepage = !laptop_mode,
+ .nr_to_reclaim = SWAP_CLUSTER_MAX,
+ .may_unmap = 1,
+ .may_swap = 1,
+ .order = 0,
+ .priority = DEF_PRIORITY,
+ .target_mem_cgroup = NULL,
+ .nodemask = NULL,
+ };
+ struct zonelist *zonelist = node_zonelist(numa_node_id(), mask);
+
+ return do_try_to_free_pages(zonelist, &sc);
+}
+
+void shrink_page_cache(gfp_t mask)
+{
+ /* We reclaim the highmem zone too, it is useful for 32bit arch */
+ __shrink_page_cache(mask | __GFP_HIGHMEM);
+}
+
/* It's optimal to keep kswapds on the same CPUs as their memory, but
not required for correctness. So if the last cpu in a node goes
away, we get changed to run anywhere: as the first one comes back,
--
1.6.0.2
--
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