From owner-svn-src-user@FreeBSD.ORG Tue Apr 20 21:51:28 2010 Return-Path: Delivered-To: svn-src-user@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id BC2AE106564A; Tue, 20 Apr 2010 21:51:28 +0000 (UTC) (envelope-from kmacy@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c]) by mx1.freebsd.org (Postfix) with ESMTP id ABB4A8FC13; Tue, 20 Apr 2010 21:51:28 +0000 (UTC) Received: from svn.freebsd.org (localhost [127.0.0.1]) by svn.freebsd.org (8.14.3/8.14.3) with ESMTP id o3KLpSYF054995; Tue, 20 Apr 2010 21:51:28 GMT (envelope-from kmacy@svn.freebsd.org) Received: (from kmacy@localhost) by svn.freebsd.org (8.14.3/8.14.3/Submit) id o3KLpSU3054992; Tue, 20 Apr 2010 21:51:28 GMT (envelope-from kmacy@svn.freebsd.org) Message-Id: <201004202151.o3KLpSU3054992@svn.freebsd.org> From: Kip Macy Date: Tue, 20 Apr 2010 21:51:28 +0000 (UTC) To: src-committers@freebsd.org, svn-src-user@freebsd.org X-SVN-Group: user MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: Subject: svn commit: r206936 - in user/kmacy/head_page_lock_2/sys/amd64: amd64 include X-BeenThere: svn-src-user@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the experimental " user" src tree" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 20 Apr 2010 21:51:28 -0000 Author: kmacy Date: Tue Apr 20 21:51:28 2010 New Revision: 206936 URL: http://svn.freebsd.org/changeset/base/206936 Log: - comment "XXX" on functions that may drop the pmap lock opening us up to race conditions - add generation counter to pmap to allow caller to know that the pmap lock was dropped Modified: user/kmacy/head_page_lock_2/sys/amd64/amd64/pmap.c user/kmacy/head_page_lock_2/sys/amd64/include/pmap.h Modified: user/kmacy/head_page_lock_2/sys/amd64/amd64/pmap.c ============================================================================== --- user/kmacy/head_page_lock_2/sys/amd64/amd64/pmap.c Tue Apr 20 21:48:48 2010 (r206935) +++ user/kmacy/head_page_lock_2/sys/amd64/amd64/pmap.c Tue Apr 20 21:51:28 2010 (r206936) @@ -566,6 +566,7 @@ pa_tryrelock(pmap_t pmap, vm_paddr_t pa, atomic_add_int((volatile int *)&pmap_tryrelock_restart, 1); PA_LOCK(pa); PMAP_LOCK(pmap); + pmap->pm_gen_count++; return (EAGAIN); } @@ -2707,23 +2708,17 @@ pmap_remove_pde(pmap_t pmap, pd_entry_t pvh = pa_to_pvh(oldpde & PG_PS_FRAME); pmap_pvh_free(pvh, pmap, sva); eva = sva + NBPDR; + panic("XXX - not properly locked"); for (va = sva, m = PHYS_TO_VM_PAGE(oldpde & PG_PS_FRAME); va < eva; va += PAGE_SIZE, m++) { - if ((oldpde & (PG_M | PG_RW | PG_A)) || - (TAILQ_EMPTY(&m->md.pv_list) && - TAILQ_EMPTY(&pvh->pv_list))) { - vm_page_lock(m); - - if ((oldpde & (PG_M | PG_RW)) == (PG_M | PG_RW)) - vm_page_dirty(m); - if (oldpde & PG_A) - vm_page_flag_set(m, PG_REFERENCED); - if (TAILQ_EMPTY(&m->md.pv_list) && - TAILQ_EMPTY(&pvh->pv_list)) - vm_page_flag_clear(m, PG_WRITEABLE); - vm_page_unlock(m); - } + if ((oldpde & (PG_M | PG_RW)) == (PG_M | PG_RW)) + vm_page_dirty(m); + if (oldpde & PG_A) + vm_page_flag_set(m, PG_REFERENCED); + if (TAILQ_EMPTY(&m->md.pv_list) && + TAILQ_EMPTY(&pvh->pv_list)) + vm_page_flag_clear(m, PG_WRITEABLE); } } if (pmap == kernel_pmap) { @@ -2991,6 +2986,11 @@ restart: continue; } else ptpaddr = *pde; + + /* + * XXX do we need to check if pmap_demote_pde dropped the lock? + * + */ } /* @@ -3017,6 +3017,10 @@ restart: */ if ((*pte & PG_G) == 0) anyvalid = 1; + /* + * XXX check if the pmap lock was dropped - maybe we need + * to restart + */ if (pmap_remove_pte(pmap, pte, sva, ptpaddr, &free)) break; } @@ -3091,7 +3095,13 @@ pmap_remove_all(vm_page_t m) if ((tpte & (PG_M | PG_RW)) == (PG_M | PG_RW)) vm_page_dirty(m); free = NULL; + + /* + * XXX pmap_unuse_pt can drop the pmap lock + * + */ pmap_unuse_pt(pmap, pv->pv_va, *pde, &free); + pmap_invalidate_page(pmap, pv->pv_va); pmap_free_zero_pages(free); TAILQ_REMOVE(&m->md.pv_list, pv, pv_list); @@ -4004,6 +4014,9 @@ retry: } if ((*pde & PG_PS) != 0) { if (!wired != ((*pde & PG_W) == 0)) { + /* + * XXX do we need to check if the pmap lock was dropped + */ if (!pmap_demote_pde(pmap, pde, va, &pv_list)) panic("pmap_change_wiring: demotion failed"); } else @@ -4460,6 +4473,10 @@ restart: vm_page_flag_clear(m, PG_WRITEABLE); } } + /* + * + * XXX check if the pmap lock has been dropped + */ pmap_unuse_pt(pmap, pv->pv_va, ptepde, &free); } } @@ -5104,6 +5121,10 @@ pmap_change_attr_locked(vm_offset_t va, tmpva += NBPDR; continue; } + /* + * XXX do we need to check if the lock was dropped + * + */ if (!pmap_demote_pde(kernel_pmap, pde, tmpva, &pv_list)) return (ENOMEM); } Modified: user/kmacy/head_page_lock_2/sys/amd64/include/pmap.h ============================================================================== --- user/kmacy/head_page_lock_2/sys/amd64/include/pmap.h Tue Apr 20 21:48:48 2010 (r206935) +++ user/kmacy/head_page_lock_2/sys/amd64/include/pmap.h Tue Apr 20 21:51:28 2010 (r206936) @@ -246,6 +246,7 @@ struct pmap { pml4_entry_t *pm_pml4; /* KVA of level 4 page table */ TAILQ_HEAD(,pv_chunk) pm_pvchunk; /* list of mappings in pmap */ u_int pm_active; /* active on cpus */ + u_int pm_gen_count; /* generation count (pmap lock dropped) */ /* spare u_int here due to padding */ struct pmap_statistics pm_stats; /* pmap statistics */ vm_page_t pm_root; /* spare page table pages */