From: Greg Kroah-Hartman Date: Thu, 27 May 2021 09:22:53 +0000 (+0200) Subject: 4.4-stable patches X-Git-Tag: v5.4.123~19 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=f74218b42b8849e104f607dc88a86a08a3bd445d;p=thirdparty%2Fkernel%2Fstable-queue.git 4.4-stable patches added patches: mm-vmstat-drop-zone-lock-in-proc-pagetypeinfo.patch --- diff --git a/queue-4.4/mm-vmstat-drop-zone-lock-in-proc-pagetypeinfo.patch b/queue-4.4/mm-vmstat-drop-zone-lock-in-proc-pagetypeinfo.patch new file mode 100644 index 00000000000..b9686835a43 --- /dev/null +++ b/queue-4.4/mm-vmstat-drop-zone-lock-in-proc-pagetypeinfo.patch @@ -0,0 +1,49 @@ +From foo@baz Thu May 27 11:14:38 AM CEST 2021 +From: Stephen Brennan +Date: Wed, 26 May 2021 10:46:13 -0700 +Subject: mm, vmstat: drop zone->lock in /proc/pagetypeinfo +To: stable@vger.kernel.org +Cc: Stephen Brennan , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Christoph Lameter , Mel Gorman , Andy Whitcroft , Aruna Ramakrishna , Khalid Aziz +Message-ID: <20210526174613.339990-1-stephen.s.brennan@oracle.com> + +From: Stephen Brennan + +Commit 93b3a674485f6a4b8ffff85d1682d5e8b7c51560 upstream + +Commit 93b3a674485f ("mm,vmstat: reduce zone->lock holding time by +/proc/pagetypeinfo") upstream caps the number of iterations over each +free_list at 100,000, and also drops the zone->lock in between each +migrate type. Capping the iteration count alters the file contents in +some cases, which means this approach may not be suitable for stable +backports. + +However, dropping zone->lock in between migrate types (and, as a result, +page orders) will not change the /proc/pagetypeinfo file contents. It +can significantly reduce the length of time spent with IRQs disabled, +which can prevent missed interrupts or soft lockups which we have +observed on systems with particularly large memory. + +Thus, this commit is a modified version of the upstream one which only +drops the lock in between migrate types. + +Fixes: 467c996c1e19 ("Print out statistics in relation to fragmentation avoidance to /proc/pagetypeinfo") +Signed-off-by: Stephen Brennan +Reviewed-by: Aruna Ramakrishna +Reviewed-by: Khalid Aziz +Signed-off-by: Greg Kroah-Hartman +--- + mm/vmstat.c | 3 +++ + 1 file changed, 3 insertions(+) + +--- a/mm/vmstat.c ++++ b/mm/vmstat.c +@@ -973,6 +973,9 @@ static void pagetypeinfo_showfree_print( + list_for_each(curr, &area->free_list[mtype]) + freecount++; + seq_printf(m, "%6lu ", freecount); ++ spin_unlock_irq(&zone->lock); ++ cond_resched(); ++ spin_lock_irq(&zone->lock); + } + seq_putc(m, '\n'); + } diff --git a/queue-4.4/series b/queue-4.4/series new file mode 100644 index 00000000000..45fd229298e --- /dev/null +++ b/queue-4.4/series @@ -0,0 +1 @@ +mm-vmstat-drop-zone-lock-in-proc-pagetypeinfo.patch