From: Ondřej Surý <ondrej@sury.org>
Date: Thu, 27 May 2021 09:04:37 +0000 (+0200)
Subject: Indicate to the kernel that we won't be needing the zone dumps
X-Git-Tag: v9.17.14~13^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e83b6569dabe12024f30184dd54d5c9737a39f6f;p=thirdparty%2Fbind9.git

Indicate to the kernel that we won't be needing the zone dumps

Add a call to posix_fadvise() to indicate to the kernel, that `named`
won't be needing the dumped zone files any time soon with:

 * POSIX_FADV_DONTNEED - The specified data will not be accessed in the
   near future.

Notes:

 POSIX_FADV_DONTNEED attempts to free cached pages associated with the
 specified region. This is useful, for example, while streaming large
 files. A program may periodically request the kernel to free cached
 data that has already been used, so that more useful cached pages are
 not discarded instead.
---

diff --git a/lib/dns/masterdump.c b/lib/dns/masterdump.c
index 0c8a400196e..c5f00bd1c33 100644
--- a/lib/dns/masterdump.c
+++ b/lib/dns/masterdump.c
@@ -1898,6 +1898,11 @@ opentmp(isc_mem_t *mctx, dns_masterformat_t format, const char *file,
 			      isc_result_totext(result));
 		goto cleanup;
 	}
+
+#if defined(POSIX_FADV_DONTNEED)
+	posix_fadvise(fileno(f), 0, 0, POSIX_FADV_DONTNEED);
+#endif
+
 	*tempp = tempname;
 	*fp = f;
 	return (ISC_R_SUCCESS);