Date: Sun, 14 Jun 2015 05:23:40 +0000 (UTC) From: Alan Cox <alc@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r284376 - head/sys/vm Message-ID: <201506140523.t5E5NebT059452@svn.freebsd.org>
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Author: alc Date: Sun Jun 14 05:23:39 2015 New Revision: 284376 URL: https://svnweb.freebsd.org/changeset/base/284376 Log: As the next step in eliminating PG_CACHE pages, free rather than cache pages in vm_pageout_scan(). The reactivation rate of cache pages created by vm_pageout_scan() is extremely low; typically no more than 0.5% to 2.25% of the pages are ever reactivated. At the same time, caching pages is more expensive than freeing them. For example, in a test with PostgreSQL, this change reduced the amount of time spent in the inactive queue scan by 1/6. Differential Revision: https://reviews.freebsd.org/D2805 Reviewed by: kib Sponsored by: EMC / Isilon Storage Division Modified: head/sys/vm/vm_pageout.c Modified: head/sys/vm/vm_pageout.c ============================================================================== --- head/sys/vm/vm_pageout.c Sun Jun 14 05:12:48 2015 (r284375) +++ head/sys/vm/vm_pageout.c Sun Jun 14 05:23:39 2015 (r284376) @@ -1233,10 +1233,10 @@ vm_pageout_scan(struct vm_domain *vmd, i --page_shortage; } else if (m->dirty == 0) { /* - * Clean pages can be placed onto the cache queue. - * This effectively frees them. + * Clean pages can be freed. */ - vm_page_cache(m); + vm_page_free(m); + PCPU_INC(cnt.v_dfree); --page_shortage; } else if ((m->flags & PG_WINATCFLS) == 0 && pass < 2) { /*
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