From: Feng Tang <feng.tang@intel.com>
To: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@kernel.org>,
David Rientjes <rientjes@google.com>,
Dave Hansen <dave.hansen@intel.com>,
Ben Widawsky <ben.widawsky@intel.com>
Cc: linux-kernel@vger.kernel.org,
Andrea Arcangeli <aarcange@redhat.com>,
Mel Gorman <mgorman@techsingularity.net>,
Mike Kravetz <mike.kravetz@oracle.com>,
Randy Dunlap <rdunlap@infradead.org>,
Vlastimil Babka <vbabka@suse.cz>, Andi Kleen <ak@linux.intel.com>,
Dan Williams <dan.j.williams@intel.com>,
ying.huang@intel.com, Feng Tang <feng.tang@intel.com>
Subject: [v3 PATCH 1/3] mm/mempolicy: cleanup nodemask intersection check for oom
Date: Mon, 31 May 2021 22:05:54 +0800 [thread overview]
Message-ID: <1622469956-82897-2-git-send-email-feng.tang@intel.com> (raw)
In-Reply-To: <1622469956-82897-1-git-send-email-feng.tang@intel.com>
mempolicy_nodemask_intersects() is used in oom case to check if a
task may have memory allocated on some memory nodes.
As it's only used by OOM check, rename it to mempolicy_in_oom_domain()
to reduce confusion.
As only for 'bind' policy, the nodemask is a force requirement for
from where to allocate memory, only do the intesection check for it,
and return true for all other policies.
Suggested-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Feng Tang <feng.tang@intel.com>
---
include/linux/mempolicy.h | 2 +-
mm/mempolicy.c | 34 +++++++++-------------------------
mm/oom_kill.c | 2 +-
3 files changed, 11 insertions(+), 27 deletions(-)
diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
index 5f1c74d..8773c55 100644
--- a/include/linux/mempolicy.h
+++ b/include/linux/mempolicy.h
@@ -150,7 +150,7 @@ extern int huge_node(struct vm_area_struct *vma,
unsigned long addr, gfp_t gfp_flags,
struct mempolicy **mpol, nodemask_t **nodemask);
extern bool init_nodemask_of_mempolicy(nodemask_t *mask);
-extern bool mempolicy_nodemask_intersects(struct task_struct *tsk,
+extern bool mempolicy_in_oom_domain(struct task_struct *tsk,
const nodemask_t *mask);
extern nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy);
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index d79fa29..6795a6a 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2094,16 +2094,16 @@ bool init_nodemask_of_mempolicy(nodemask_t *mask)
#endif
/*
- * mempolicy_nodemask_intersects
+ * mempolicy_in_oom_domain
*
- * If tsk's mempolicy is "default" [NULL], return 'true' to indicate default
- * policy. Otherwise, check for intersection between mask and the policy
- * nodemask for 'bind' or 'interleave' policy. For 'preferred' or 'local'
- * policy, always return true since it may allocate elsewhere on fallback.
+ * If tsk's mempolicy is "bind", check for intersection between mask and
+ * the policy nodemask. Otherwise, return true for all other policies
+ * including "interleave", as a tsk with "interleave" policy may have
+ * memory allocated from all nodes in system.
*
* Takes task_lock(tsk) to prevent freeing of its mempolicy.
*/
-bool mempolicy_nodemask_intersects(struct task_struct *tsk,
+bool mempolicy_in_oom_domain(struct task_struct *tsk,
const nodemask_t *mask)
{
struct mempolicy *mempolicy;
@@ -2111,29 +2111,13 @@ bool mempolicy_nodemask_intersects(struct task_struct *tsk,
if (!mask)
return ret;
+
task_lock(tsk);
mempolicy = tsk->mempolicy;
- if (!mempolicy)
- goto out;
-
- switch (mempolicy->mode) {
- case MPOL_PREFERRED:
- /*
- * MPOL_PREFERRED and MPOL_F_LOCAL are only preferred nodes to
- * allocate from, they may fallback to other nodes when oom.
- * Thus, it's possible for tsk to have allocated memory from
- * nodes in mask.
- */
- break;
- case MPOL_BIND:
- case MPOL_INTERLEAVE:
+ if (mempolicy && mempolicy->mode == MPOL_BIND)
ret = nodes_intersects(mempolicy->v.nodes, *mask);
- break;
- default:
- BUG();
- }
-out:
task_unlock(tsk);
+
return ret;
}
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index eefd3f5..fcc29e9 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -104,7 +104,7 @@ static bool oom_cpuset_eligible(struct task_struct *start,
* mempolicy intersects current, otherwise it may be
* needlessly killed.
*/
- ret = mempolicy_nodemask_intersects(tsk, mask);
+ ret = mempolicy_in_oom_domain(tsk, mask);
} else {
/*
* This is not a mempolicy constrained oom, so only
--
2.7.4
next prev parent reply other threads:[~2021-05-31 15:15 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-31 14:05 [v3 PATCH 0/3] mm/mempolicy: some fix and semantics cleanup Feng Tang
2021-05-31 14:05 ` Feng Tang [this message]
2021-06-01 8:19 ` [v3 PATCH 1/3] mm/mempolicy: cleanup nodemask intersection check for oom Michal Hocko
2021-06-01 11:08 ` Feng Tang
2021-06-01 23:56 ` Andrew Morton
2021-05-31 14:05 ` [v3 PATCH 2/3] mm/mempolicy: don't handle MPOL_LOCAL like a fake MPOL_PREFERRED policy Feng Tang
2021-06-01 8:44 ` Michal Hocko
2021-06-01 11:29 ` Feng Tang
2021-05-31 14:05 ` [v3 PATCH 3/3] mm/mempolicy: unify the parameter sanity check for mbind and set_mempolicy Feng Tang
2021-06-01 8:46 ` Michal Hocko
2021-05-31 21:41 ` [v3 PATCH 0/3] mm/mempolicy: some fix and semantics cleanup Andrew Morton
2021-06-01 0:55 ` Feng Tang
2021-06-01 8:48 ` Michal Hocko
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