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authorDave Hansen <dave.hansen@linux.intel.com>2021-05-05 03:36:04 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2021-05-05 20:27:23 +0200
commit202e35db5e719ee8af6028183403f475e243f82d (patch)
tree2d0c7f0c9d70036a3c5bc39056a51264ac3ac1c0
parentmm/vmscan: move RECLAIM* bits to uapi header (diff)
downloadlinux-202e35db5e719ee8af6028183403f475e243f82d.tar.xz
linux-202e35db5e719ee8af6028183403f475e243f82d.zip
mm/vmscan: replace implicit RECLAIM_ZONE checks with explicit checks
RECLAIM_ZONE was assumed to be unused because it was never explicitly used in the kernel. However, there were a number of places where it was checked implicitly by checking 'node_reclaim_mode' for a zero value. These zero checks are not great because it is not obvious what a zero mode *means* in the code. Replace them with a helper which makes it more obvious: node_reclaim_enabled(). This helper also provides a handy place to explicitly check the RECLAIM_ZONE bit itself. Check it explicitly there to make it more obvious where the bit can affect behavior. This should have no functional impact. Link: https://lkml.kernel.org/r/20210219172559.BF589C44@viggo.jf.intel.com Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Ben Widawsky <ben.widawsky@intel.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Acked-by: Christoph Lameter <cl@linux.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Alex Shi <alex.shi@linux.alibaba.com> Cc: "Tobin C. Harding" <tobin@kernel.org> Cc: Huang Ying <ying.huang@intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Qian Cai <cai@lca.pw> Cc: Daniel Wagner <dwagner@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/swap.h7
-rw-r--r--mm/khugepaged.c2
-rw-r--r--mm/page_alloc.c2
3 files changed, 9 insertions, 2 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 4cc6ec3bf0ab..42191da1bdc9 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -12,6 +12,7 @@
#include <linux/fs.h>
#include <linux/atomic.h>
#include <linux/page-flags.h>
+#include <uapi/linux/mempolicy.h>
#include <asm/page.h>
struct notifier_block;
@@ -378,6 +379,12 @@ extern int sysctl_min_slab_ratio;
#define node_reclaim_mode 0
#endif
+static inline bool node_reclaim_enabled(void)
+{
+ /* Is any node_reclaim_mode bit set? */
+ return node_reclaim_mode & (RECLAIM_ZONE|RECLAIM_WRITE|RECLAIM_UNMAP);
+}
+
extern void check_move_unevictable_pages(struct pagevec *pvec);
extern int kswapd_run(int nid);
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index a03569eda183..ea74da3232ab 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -809,7 +809,7 @@ static bool khugepaged_scan_abort(int nid)
* If node_reclaim_mode is disabled, then no extra effort is made to
* allocate memory locally.
*/
- if (!node_reclaim_mode)
+ if (!node_reclaim_enabled())
return false;
/* If there is a count for this node already, it must be acceptable */
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 80fa6e0f9ed9..19cdd8a829dc 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3968,7 +3968,7 @@ retry:
if (alloc_flags & ALLOC_NO_WATERMARKS)
goto try_this_zone;
- if (node_reclaim_mode == 0 ||
+ if (!node_reclaim_enabled() ||
!zone_allows_reclaim(ac->preferred_zoneref->zone, zone))
continue;