Date: Thu, 19 Oct 2017 06:08:32 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 223059] [patch] consider skipped 2 pages in sw_nblks and add size check before blist_alloc Message-ID: <bug-223059-8-Z6BXBUhnYN@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-223059-8@https.bugs.freebsd.org/bugzilla/> References: <bug-223059-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=223059 --- Comment #1 from Alan Cox <alc@FreeBSD.org> --- Testing "(sp->sw_nblks - sp->sw_used >= npages)" before every call to blist_alloc() is of no real benefit. In the common case, where there is available swap space, it is added overhead, albeit a tiny amount of overhead. Only in the rare case, where there is no swap space available will it be of any benefit. But, in that case, the gain is minimal. The hinting mechanism in the blist code will quickly conclude that there is no available space, and return failure. In summary, the tiny amount of overhead in the common case is going to outweigh the gain in the rare case. -- You are receiving this mail because: You are the assignee for the bug.
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