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authorJakub Matěna <matenajakub@gmail.com>2022-06-03 16:57:19 +0200
committerAndrew Morton <akpm@linux-foundation.org>2022-09-26 19:46:28 -0700
commitca3d76b0aa808a06997297d123b66d17b81e5285 (patch)
treecbca7060ab3c097fab66fd9c96ae816e149ed9a0 /mm/mremap.c
parenteef199440df950942b3c7ef2e2de507fd6ced031 (diff)
mm: add merging after mremap resize
When mremap call results in expansion, it might be possible to merge the VMA with the next VMA which might become adjacent. This patch adds vma_merge call after the expansion is done to try and merge. [akpm@linux-foundation.org: coding-style cleanups] Link: https://lkml.kernel.org/r/20220603145719.1012094-3-matenajakub@gmail.com Signed-off-by: Jakub Matěna <matenajakub@gmail.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: "Kirill A . Shutemov" <kirill@shutemov.name> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/mremap.c')
-rw-r--r--mm/mremap.c19
1 files changed, 17 insertions, 2 deletions
diff --git a/mm/mremap.c b/mm/mremap.c
index 8644ff278f02..e465ffe279bb 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -9,6 +9,7 @@
*/
#include <linux/mm.h>
+#include <linux/mm_inline.h>
#include <linux/hugetlb.h>
#include <linux/shm.h>
#include <linux/ksm.h>
@@ -23,6 +24,7 @@
#include <linux/mmu_notifier.h>
#include <linux/uaccess.h>
#include <linux/userfaultfd_k.h>
+#include <linux/mempolicy.h>
#include <asm/cacheflush.h>
#include <asm/tlb.h>
@@ -1012,6 +1014,9 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
/* can we just expand the current mapping? */
if (vma_expandable(vma, new_len - old_len)) {
long pages = (new_len - old_len) >> PAGE_SHIFT;
+ unsigned long extension_start = addr + old_len;
+ unsigned long extension_end = addr + new_len;
+ pgoff_t extension_pgoff = vma->vm_pgoff + (old_len >> PAGE_SHIFT);
if (vma->vm_flags & VM_ACCOUNT) {
if (security_vm_enough_memory_mm(mm, pages)) {
@@ -1020,8 +1025,18 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
}
}
- if (vma_adjust(vma, vma->vm_start, addr + new_len,
- vma->vm_pgoff, NULL)) {
+ /*
+ * Function vma_merge() is called on the extension we are adding to
+ * the already existing vma, vma_merge() will merge this extension with
+ * the already existing vma (expand operation itself) and possibly also
+ * with the next vma if it becomes adjacent to the expanded vma and
+ * otherwise compatible.
+ */
+ vma = vma_merge(mm, vma, extension_start, extension_end,
+ vma->vm_flags, vma->anon_vma, vma->vm_file,
+ extension_pgoff, vma_policy(vma),
+ vma->vm_userfaultfd_ctx, anon_vma_name(vma));
+ if (!vma) {
vm_unacct_memory(pages);
ret = -ENOMEM;
goto out;