Tidy up mem_cgroup_charge_common before extending it. Adjust some
comments, but mainly clean up its loop: I've an aversion to loops
full of continues, then a break or a goto at the bottom. And the
is_atomic test should be on the __GFP_WAIT bit, not GFP_ATOMIC bits.
Signed-off-by: Hugh Dickins <[email protected]>
---
mm/memcontrol.c | 44 +++++++++++++++-----------------------------
1 file changed, 15 insertions(+), 29 deletions(-)
--- 2.6.24-rc5-mm1/mm/memcontrol.c 2007-12-05 10:38:45.000000000 +0000
+++ memcgroup1/mm/memcontrol.c 2007-12-06 19:35:52.000000000 +0000
@@ -604,23 +604,22 @@ retry:
goto done;
}
}
-
unlock_page_cgroup(page);
pc = kzalloc(sizeof(struct page_cgroup), gfp_mask);
if (pc == NULL)
goto err;
- rcu_read_lock();
/*
- * We always charge the cgroup the mm_struct belongs to
- * the mm_struct's mem_cgroup changes on task migration if the
+ * We always charge the cgroup the mm_struct belongs to.
+ * The mm_struct's mem_cgroup changes on task migration if the
* thread group leader migrates. It's possible that mm is not
* set, if so charge the init_mm (happens for pagecache usage).
*/
if (!mm)
mm = &init_mm;
+ rcu_read_lock();
mem = rcu_dereference(mm->mem_cgroup);
/*
* For every charge from the cgroup, increment reference
@@ -634,12 +633,8 @@ retry:
* the cgroup limit.
*/
while (res_counter_charge(&mem->res, PAGE_SIZE)) {
- bool is_atomic = gfp_mask & GFP_ATOMIC;
- /*
- * We cannot reclaim under GFP_ATOMIC, fail the charge
- */
- if (is_atomic)
- goto noreclaim;
+ if (!(gfp_mask & __GFP_WAIT))
+ goto out;
if (try_to_free_mem_cgroup_pages(mem, gfp_mask))
continue;
@@ -653,23 +648,12 @@ retry:
*/
if (res_counter_check_under_limit(&mem->res))
continue;
- /*
- * Since we control both RSS and cache, we end up with a
- * very interesting scenario where we end up reclaiming
- * memory (essentially RSS), since the memory is pushed
- * to swap cache, we eventually end up adding those
- * pages back to our list. Hence we give ourselves a
- * few chances before we fail
- */
- else if (nr_retries--) {
- congestion_wait(WRITE, HZ/10);
- continue;
+
+ if (!nr_retries--) {
+ mem_cgroup_out_of_memory(mem, gfp_mask);
+ goto out;
}
-noreclaim:
- css_put(&mem->css);
- if (!is_atomic)
- mem_cgroup_out_of_memory(mem, GFP_KERNEL);
- goto free_pc;
+ congestion_wait(WRITE, HZ/10);
}
atomic_set(&pc->ref_cnt, 1);
@@ -678,10 +662,11 @@ noreclaim:
pc->flags = PAGE_CGROUP_FLAG_ACTIVE;
if (ctype == MEM_CGROUP_CHARGE_TYPE_CACHE)
pc->flags |= PAGE_CGROUP_FLAG_CACHE;
+
if (page_cgroup_assign_new_page_cgroup(page, pc)) {
/*
- * an another charge is added to this page already.
- * we do take lock_page_cgroup(page) again and read
+ * Another charge has been added to this page already.
+ * We take lock_page_cgroup(page) again and read
* page->cgroup, increment refcnt.... just retry is OK.
*/
res_counter_uncharge(&mem->res, PAGE_SIZE);
@@ -698,7 +683,8 @@ noreclaim:
done:
return 0;
-free_pc:
+out:
+ css_put(&mem->css);
kfree(pc);
err:
return -ENOMEM;
--
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