Date: Tue, 25 Feb 2020 12:02:29 -0800 From: Ravi Pokala <rpokala@freebsd.org> To: Gleb Smirnoff <glebius@FreeBSD.org>, <src-committers@freebsd.org>, <svn-src-all@freebsd.org>, <svn-src-head@freebsd.org> Subject: Re: svn commit: r358317 - head/sys/kern Message-ID: <23A820B4-2E13-4E3E-B734-C7950298C286@panasas.com> In-Reply-To: <202002251911.01PJBLDP091875@repo.freebsd.org> References: <202002251911.01PJBLDP091875@repo.freebsd.org>
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-----Original Message-----
From: <owner-src-committers@freebsd.org> on behalf of Gleb Smirnoff <glebius@FreeBSD.org>
Date: 2020-02-25, Tuesday at 11:11
To: <src-committers@freebsd.org>, <svn-src-all@freebsd.org>, <svn-src-head@freebsd.org>
Subject: svn commit: r358317 - head/sys/kern
Author: glebius
Date: Tue Feb 25 19:11:20 2020
New Revision: 358317
URL: https://svnweb.freebsd.org/changeset/base/358317
Log:
When sendfile_swapin() sweeps through pages in search for a bogus page
skip first and last pages. This is a micro optimisation.
Yes, but *why* skip the first and last pages?
-Ravi
Modified:
head/sys/kern/kern_sendfile.c
Modified: head/sys/kern/kern_sendfile.c
==============================================================================
--- head/sys/kern/kern_sendfile.c Tue Feb 25 19:04:39 2020 (r358316)
+++ head/sys/kern/kern_sendfile.c Tue Feb 25 19:11:20 2020 (r358317)
@@ -462,7 +462,7 @@ sendfile_swapin(vm_object_t obj, struct sf_io *sfio, i
* Restore the valid page pointers. They are already
* unbusied, but still wired.
*/
- for (j = i; j < i + count; j++)
+ for (j = i + 1; j < i + count - 1; j++)
if (pa[j] == bogus_page) {
pa[j] = vm_page_lookup(obj,
OFF_TO_IDX(vmoff(j, off)));
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