Date: Mon, 16 Mar 2015 14:24:48 +0000 (UTC) From: Gleb Smirnoff <glebius@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r280136 - head/sys/vm Message-ID: <201503161424.t2GEOm0D041812@svn.freebsd.org>
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Author: glebius Date: Mon Mar 16 14:24:47 2015 New Revision: 280136 URL: https://svnweb.freebsd.org/changeset/base/280136 Log: Provide a comment explaining r279688. Suggested by: alc Modified: head/sys/vm/vnode_pager.c Modified: head/sys/vm/vnode_pager.c ============================================================================== --- head/sys/vm/vnode_pager.c Mon Mar 16 14:12:41 2015 (r280135) +++ head/sys/vm/vnode_pager.c Mon Mar 16 14:24:47 2015 (r280136) @@ -772,6 +772,14 @@ vnode_pager_generic_getpages(struct vnod bsize = vp->v_mount->mnt_stat.f_iosize; foff = IDX_TO_OFF(m[reqpage]->pindex); + /* + * Synchronous and asynchronous paging operations use different + * free pbuf counters. This is done to avoid asynchronous requests + * to consume all pbufs. + * Allocate the pbuf at the very beginning of the function, so that + * if we are low on certain kind of pbufs don't even proceed to BMAP, + * but sleep. + */ freecnt = iodone != NULL ? &vnode_async_pbuf_freecnt : &vnode_pbuf_freecnt; bp = getpbuf(freecnt);
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