5.15-stable patches

added patches:
	mm-page_alloc-unreserve-highatomic-page-blocks-before-oom.patch

diff --git a/queue-5.15/mm-page_alloc-unreserve-highatomic-page-blocks-before-oom.patch b/queue-5.15/mm-page_alloc-unreserve-highatomic-page-blocks-before-oom.patch
new file mode 100644 (file)
index 0000000..44af3ce
--- /dev/null
+++ b/queue-5.15/mm-page_alloc-unreserve-highatomic-page-blocks-before-oom.patch
@@ -0,0 +1,104 @@
+From ac3f3b0a55518056bc80ed32a41931c99e1f7d81 Mon Sep 17 00:00:00 2001
+From: Charan Teja Kalla <quic_charante@quicinc.com>
+Date: Fri, 24 Nov 2023 16:27:25 +0530
+Subject: mm: page_alloc: unreserve highatomic page blocks before oom
+
+From: Charan Teja Kalla <quic_charante@quicinc.com>
+
+commit ac3f3b0a55518056bc80ed32a41931c99e1f7d81 upstream.
+
+__alloc_pages_direct_reclaim() is called from slowpath allocation where
+high atomic reserves can be unreserved after there is a progress in
+reclaim and yet no suitable page is found.  Later should_reclaim_retry()
+gets called from slow path allocation to decide if the reclaim needs to be
+retried before OOM kill path is taken.
+
+should_reclaim_retry() checks the available(reclaimable + free pages)
+memory against the min wmark levels of a zone and returns:
+
+a) true, if it is above the min wmark so that slow path allocation will
+   do the reclaim retries.
+
+b) false, thus slowpath allocation takes oom kill path.
+
+should_reclaim_retry() can also unreserves the high atomic reserves **but
+only after all the reclaim retries are exhausted.**
+
+In a case where there are almost none reclaimable memory and free pages
+contains mostly the high atomic reserves but allocation context can't use
+these high atomic reserves, makes the available memory below min wmark
+levels hence false is returned from should_reclaim_retry() leading the
+allocation request to take OOM kill path.  This can turn into a early oom
+kill if high atomic reserves are holding lot of free memory and
+unreserving of them is not attempted.
+
+(early)OOM is encountered on a VM with the below state:
+[  295.998653] Normal free:7728kB boost:0kB min:804kB low:1004kB
+high:1204kB reserved_highatomic:8192KB active_anon:4kB inactive_anon:0kB
+active_file:24kB inactive_file:24kB unevictable:1220kB writepending:0kB
+present:70732kB managed:49224kB mlocked:0kB bounce:0kB free_pcp:688kB
+local_pcp:492kB free_cma:0kB
+[  295.998656] lowmem_reserve[]: 0 32
+[  295.998659] Normal: 508*4kB (UMEH) 241*8kB (UMEH) 143*16kB (UMEH)
+33*32kB (UH) 7*64kB (UH) 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB
+0*4096kB = 7752kB
+
+Per above log, the free memory of ~7MB exist in the high atomic reserves
+is not freed up before falling back to oom kill path.
+
+Fix it by trying to unreserve the high atomic reserves in
+should_reclaim_retry() before __alloc_pages_direct_reclaim() can fallback
+to oom kill path.
+
+Link: https://lkml.kernel.org/r/1700823445-27531-1-git-send-email-quic_charante@quicinc.com
+Fixes: 0aaa29a56e4f ("mm, page_alloc: reserve pageblocks for high-order atomic allocations on demand")
+Signed-off-by: Charan Teja Kalla <quic_charante@quicinc.com>
+Reported-by: Chris Goldsworthy <quic_cgoldswo@quicinc.com>
+Suggested-by: Michal Hocko <mhocko@suse.com>
+Acked-by: Michal Hocko <mhocko@suse.com>
+Acked-by: David Rientjes <rientjes@google.com>
+Cc: Chris Goldsworthy <quic_cgoldswo@quicinc.com>
+Cc: David Hildenbrand <david@redhat.com>
+Cc: Johannes Weiner <hannes@cmpxchg.org>
+Cc: Mel Gorman <mgorman@techsingularity.net>
+Cc: Pavankumar Kondeti <quic_pkondeti@quicinc.com>
+Cc: Vlastimil Babka <vbabka@suse.cz>
+Cc: Joakim Tjernlund <Joakim.Tjernlund@infinera.com>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ mm/page_alloc.c |   16 ++++++++--------
+ 1 file changed, 8 insertions(+), 8 deletions(-)
+
+--- a/mm/page_alloc.c
++++ b/mm/page_alloc.c
+@@ -4793,14 +4793,9 @@ should_reclaim_retry(gfp_t gfp_mask, uns
+       else
+               (*no_progress_loops)++;
+ 
+-      /*
+-       * Make sure we converge to OOM if we cannot make any progress
+-       * several times in the row.
+-       */
+-      if (*no_progress_loops > MAX_RECLAIM_RETRIES) {
+-              /* Before OOM, exhaust highatomic_reserve */
+-              return unreserve_highatomic_pageblock(ac, true);
+-      }
++      if (*no_progress_loops > MAX_RECLAIM_RETRIES)
++              goto out;
++
+ 
+       /*
+        * Keep reclaiming pages while there is a chance this will lead
+@@ -4862,6 +4857,11 @@ out:
+               schedule_timeout_uninterruptible(1);
+       else
+               cond_resched();
++out:
++      /* Before OOM, exhaust highatomic_reserve */
++      if (!ret)
++              return unreserve_highatomic_pageblock(ac, true);
++
+       return ret;
+ }
+ 

diff --git a/queue-5.15/series b/queue-5.15/series
index 533cadc0642bfc4ef4aeb7dfb92a9e6b86f47356..6328559d43c9d20564426d466c4bf407c2dbf4e5 100644 (file)
--- a/queue-5.15/series
+++ b/queue-5.15/series
@@ -40,3 +40,4 @@ rtc-adjust-failure-return-code-for-cmos_set_alarm.patch
 nouveau-vmm-don-t-set-addr-on-the-fail-path-to-avoid-warning.patch
 ubifs-ubifs_symlink-fix-memleak-of-inode-i_link-in-error-path.patch
 rename-fix-the-locking-of-subdirectories.patch
+mm-page_alloc-unreserve-highatomic-page-blocks-before-oom.patch