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From: Hugh Dickins <hughd@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Andi Kleen <ak@linux.intel.com>, Christoph Lameter <cl@linux.com>,
	 Matthew Wilcox <willy@infradead.org>,
	 Mike Kravetz <mike.kravetz@oracle.com>,
	 David Hildenbrand <david@redhat.com>,
	 Suren Baghdasaryan <surenb@google.com>,
	Yang Shi <shy828301@gmail.com>,
	 Sidhartha Kumar <sidhartha.kumar@oracle.com>,
	 Vishal Moola <vishal.moola@gmail.com>,
	 Kefeng Wang <wangkefeng.wang@huawei.com>,
	 Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Tejun Heo <tj@kernel.org>,
	 Mel Gorman <mgorman@techsingularity.net>,
	Michal Hocko <mhocko@suse.com>,
	 "Huang, Ying" <ying.huang@intel.com>,
	linux-kernel@vger.kernel.org,  linux-mm@kvack.org
Subject: [PATCH v2 06/12] mempolicy trivia: use pgoff_t in shared mempolicy tree
Date: Tue, 3 Oct 2023 02:21:34 -0700 (PDT)	[thread overview]
Message-ID: <5451157-3818-4af5-fd2c-5d26a5d1dc53@google.com> (raw)
In-Reply-To: <ebc0987e-beff-8bfb-9283-234c2cbd17c5@google.com>

Prefer the more explicit "pgoff_t" to "unsigned long" when dealing with
a shared mempolicy tree.  Delete confusing comment about pseudo mm vmas.

Signed-off-by: Hugh Dickins <hughd@google.com>
---
 include/linux/mempolicy.h | 20 +++++++-------------
 mm/mempolicy.c            | 12 ++++++------
 2 files changed, 13 insertions(+), 19 deletions(-)

diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
index 325b7200c311..c69f9480d5e4 100644
--- a/include/linux/mempolicy.h
+++ b/include/linux/mempolicy.h
@@ -107,22 +107,16 @@ static inline bool mpol_equal(struct mempolicy *a, struct mempolicy *b)
 
 /*
  * Tree of shared policies for a shared memory region.
- * Maintain the policies in a pseudo mm that contains vmas. The vmas
- * carry the policy. As a special twist the pseudo mm is indexed in pages, not
- * bytes, so that we can work with shared memory segments bigger than
- * unsigned long.
  */
-
-struct sp_node {
-	struct rb_node nd;
-	unsigned long start, end;
-	struct mempolicy *policy;
-};
-
 struct shared_policy {
 	struct rb_root root;
 	rwlock_t lock;
 };
+struct sp_node {
+	struct rb_node nd;
+	pgoff_t start, end;
+	struct mempolicy *policy;
+};
 
 int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst);
 void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol);
@@ -130,7 +124,7 @@ int mpol_set_shared_policy(struct shared_policy *sp,
 			   struct vm_area_struct *vma, struct mempolicy *mpol);
 void mpol_free_shared_policy(struct shared_policy *sp);
 struct mempolicy *mpol_shared_policy_lookup(struct shared_policy *sp,
-					    unsigned long idx);
+					    pgoff_t idx);
 
 struct mempolicy *get_task_policy(struct task_struct *p);
 struct mempolicy *__get_vma_policy(struct vm_area_struct *vma,
@@ -216,7 +210,7 @@ static inline void mpol_free_shared_policy(struct shared_policy *sp)
 }
 
 static inline struct mempolicy *
-mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
+mpol_shared_policy_lookup(struct shared_policy *sp, pgoff_t idx)
 {
 	return NULL;
 }
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index c7906a034959..1d3f9e1ecbb8 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2448,8 +2448,8 @@ bool __mpol_equal(struct mempolicy *a, struct mempolicy *b)
  * lookup first element intersecting start-end.  Caller holds sp->lock for
  * reading or for writing
  */
-static struct sp_node *
-sp_lookup(struct shared_policy *sp, unsigned long start, unsigned long end)
+static struct sp_node *sp_lookup(struct shared_policy *sp,
+					pgoff_t start, pgoff_t end)
 {
 	struct rb_node *n = sp->root.rb_node;
 
@@ -2503,8 +2503,8 @@ static void sp_insert(struct shared_policy *sp, struct sp_node *new)
 }
 
 /* Find shared policy intersecting idx */
-struct mempolicy *
-mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
+struct mempolicy *mpol_shared_policy_lookup(struct shared_policy *sp,
+						pgoff_t idx)
 {
 	struct mempolicy *pol = NULL;
 	struct sp_node *sn;
@@ -2672,8 +2672,8 @@ static struct sp_node *sp_alloc(unsigned long start, unsigned long end,
 }
 
 /* Replace a policy range. */
-static int shared_policy_replace(struct shared_policy *sp, unsigned long start,
-				 unsigned long end, struct sp_node *new)
+static int shared_policy_replace(struct shared_policy *sp, pgoff_t start,
+				 pgoff_t end, struct sp_node *new)
 {
 	struct sp_node *n;
 	struct sp_node *n_new = NULL;
-- 
2.35.3



  parent reply	other threads:[~2023-10-03  9:21 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-03  9:12 [PATCH v2 00/12] mempolicy: cleanups leading to NUMA mpol without vma Hugh Dickins
2023-10-03  9:15 ` [PATCH v2 01/12] hugetlbfs: drop shared NUMA mempolicy pretence Hugh Dickins
2023-10-03  9:16 ` [PATCH v2 02/12] kernfs: drop shared NUMA mempolicy hooks Hugh Dickins
2023-10-03  9:17 ` [PATCH v2 03/12] mempolicy: fix migrate_pages(2) syscall return nr_failed Hugh Dickins
2023-10-07  7:27   ` Huang, Ying
2023-10-03  9:19 ` [PATCH v2 04/12] mempolicy trivia: delete those ancient pr_debug()s Hugh Dickins
2023-10-03  9:20 ` [PATCH v2 05/12] mempolicy trivia: slightly more consistent naming Hugh Dickins
2023-10-03  9:21 ` Hugh Dickins [this message]
2023-10-03  9:22 ` [PATCH v2 07/12] mempolicy: mpol_shared_policy_init() without pseudo-vma Hugh Dickins
2023-10-03  9:24 ` [PATCH v2 08/12] mempolicy: remove confusing MPOL_MF_LAZY dead code Hugh Dickins
2023-10-03 22:28   ` Yang Shi
2023-10-03  9:25 ` [PATCH v2 09/12] mm: add page_rmappable_folio() wrapper Hugh Dickins
2023-10-03  9:26 ` [PATCH v2 10/12] mempolicy: alloc_pages_mpol() for NUMA policy without vma Hugh Dickins
2023-10-19 20:39   ` [PATCH v3 " Hugh Dickins
2023-10-23 16:53     ` domenico cerasuolo
2023-10-23 17:53       ` Andrew Morton
2023-10-23 18:10         ` domenico cerasuolo
2023-10-23 19:05           ` Johannes Weiner
2023-10-23 19:48             ` Hugh Dickins
2023-10-24  6:44             ` [PATCH] mempolicy: alloc_pages_mpol() for NUMA policy without vma: fix Hugh Dickins
2023-10-24  8:17               ` kernel test robot
2023-10-24 15:56                 ` Hugh Dickins
2023-10-24 16:09               ` [PATCH v2] " Hugh Dickins
2023-10-23 18:34     ` [PATCH v3 10/12] mempolicy: alloc_pages_mpol() for NUMA policy without vma Zi Yan
2023-10-23 21:10       ` Hugh Dickins
2023-10-23 21:13         ` Zi Yan
2023-10-03  9:27 ` [PATCH v2 11/12] mempolicy: mmap_lock is not needed while migrating folios Hugh Dickins
2023-10-03  9:29 ` [PATCH v2 12/12] mempolicy: migration attempt to match interleave nodes Hugh Dickins
2023-10-24  6:50   ` [PATCH] mempolicy: migration attempt to match interleave nodes: fix Hugh Dickins
2023-10-24 15:18     ` Liam R. Howlett
2023-10-24 16:32       ` Hugh Dickins
2023-10-24 16:45         ` Matthew Wilcox

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