Date: Wed, 6 Apr 2022 02:07:47 +0000 From: HAGIO KAZUHITO(?????) <k-hagio-ab(a)nec.com&gt; To: Huang Shijie <shijie(a)os.amperecomputing.com&gt;, &quot;lijiang(a)redhat.com&quot; <lijiang(a)redhat.com&gt; Cc: &quot;patches(a)amperecomputing.com&quot; <patches(a)amperecomputing.com&gt;, &quot;zwang(a)amperecomputing.com&quot; <zwang(a)amperecomputing.com&gt;, &quot;darren(a)os.amperecomputing.com&quot; <darren(a)os.amperecomputing.com&gt;, &quot;crash-utility(a)redhat.com&quot; <crash-utility(a)redhat.com&gt; Subject: Re: [Crash-utility] [PATCH v2] diskdump: use mmap/madvise to improve the start-up Message-ID: < TYYPR01MB67776D37C6B5F947EBAE6750DDE79(a)TYYPR01MB6777.jpnprd01.prod.outlook.com > Content-Type: text/plain; charset="iso-2022-jp" -----Original Message----- > 1.) The bitmap of vmcore file can be very big in the server kernel panic, > such as over 256M. > > This patch uses mmap/madvise to improve the read speed > of the bitmap in the non-FLAT_FORMAT code path. > > Use MADV_WILLNEED for madvise, it will trigger read ahead for > reading the bitmap. Thanks for the update. With removing the unused variables (will be fixed when merging), Acked-by: Kazuhito Hagio <k-hagio-ab(a)nec.com&gt; $ make clean ; make warn diskdump.c: In function ?read_dump_header?: diskdump.c:543:10: warning: unused variable ?bytes_read? [-Wunused-variable] ssize_t bytes_read; ^~~~~~~~~~ diskdump.c:542:9: warning: unused variable ?len? [-Wunused-variable] size_t len; ^~~ diskdump.c:541:8: warning: unused variable ?bufptr? [-Wunused-variable] char *bufptr; ^~~~~~

As for a second ack, please wait for a while. Lianbo is taking a leave and will be back soon. Thanks, Kazu