From: Zhang Boyang <zhangboyang.id@gmail.com>
Date: Sat, 15 Oct 2022 14:15:11 +0000 (+0800)
Subject: mm: Try invalidate disk caches last when out of memory
X-Git-Tag: grub-2.12-rc1~248
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=17975d10a80e2457e5237f87fa58a7943031983e;p=thirdparty%2Fgrub.git

mm: Try invalidate disk caches last when out of memory

Every heap grow will cause all disk caches invalidated which decreases
performance severely. This patch moves disk cache invalidation code to
the last of memory squeezing measures. So, disk caches are released only
when there are no other ways to get free memory.

Signed-off-by: Zhang Boyang <zhangboyang.id@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Patrick Steinhardt <ps@pks.im>
---

diff --git a/grub-core/kern/mm.c b/grub-core/kern/mm.c
index 75f6eacbe..ae2279133 100644
--- a/grub-core/kern/mm.c
+++ b/grub-core/kern/mm.c
@@ -443,12 +443,6 @@ grub_memalign (grub_size_t align, grub_size_t size)
   switch (count)
     {
     case 0:
-      /* Invalidate disk caches.  */
-      grub_disk_cache_invalidate_all ();
-      count++;
-      goto again;
-
-    case 1:
       /* Request additional pages, contiguous */
       count++;
 
@@ -458,7 +452,7 @@ grub_memalign (grub_size_t align, grub_size_t size)
 
       /* fallthrough  */
 
-    case 2:
+    case 1:
       /* Request additional pages, anything at all */
       count++;
 
@@ -474,6 +468,12 @@ grub_memalign (grub_size_t align, grub_size_t size)
 
       /* fallthrough */
 
+    case 2:
+      /* Invalidate disk caches.  */
+      grub_disk_cache_invalidate_all ();
+      count++;
+      goto again;
+
     default:
       break;
     }