From mboxrd@z Thu Jan 1 00:00:00 1970 From: Olaf Hering Subject: [PATCH 08/12] xenpaging: drop paged pages in guest_remove_page Date: Mon, 10 Jan 2011 17:43:53 +0100 Message-ID: <20110110164348.394538387@aepfle.de> References: <20110110164345.521919826@aepfle.de> Return-path: Content-Disposition: inline; filename=xen-unstable.xenpaging.guest_remove_page.patch List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org Simply drop paged-pages in guest_remove_page(), and notify xenpaging to drop its reference to the gfn. If the ring is full, the page will remain in paged-out state in xenpaging. This is not an issue, it just means this gfn will not be nominated again. Signed-off-by: Olaf Hering --- v3: send one-way notification to pager to release page use new mem_event_check_ring() feature to not pause vcpu when ring is full v2: resume dropped page to unpause vcpus tools/xenpaging/xenpaging.c | 39 ++++++++++++++++++++------------ xen/arch/x86/mm/p2m.c | 49 ++++++++++++++++++++++++++++++----------- xen/common/memory.c | 6 +++++ xen/include/asm-x86/p2m.h | 4 +++ xen/include/public/mem_event.h | 1 5 files changed, 72 insertions(+), 27 deletions(-) --- xen-unstable.hg-4.1.22694.orig/tools/xenpaging/xenpaging.c +++ xen-unstable.hg-4.1.22694/tools/xenpaging/xenpaging.c @@ -638,25 +638,34 @@ int main(int argc, char *argv[]) goto out; } - /* Populate the page */ - rc = xenpaging_populate_page(paging, &req.gfn, fd, i); - if ( rc != 0 ) + if ( req.flags & MEM_EVENT_FLAG_DROP_PAGE ) { - ERROR("Error populating page"); - goto out; + DPRINTF("drop_page ^ gfn %"PRIx64" pageslot %d\n", req.gfn, i); + /* Notify policy of page being dropped */ + policy_notify_paged_in(req.gfn); } + else + { + /* Populate the page */ + rc = xenpaging_populate_page(paging, &req.gfn, fd, i); + if ( rc != 0 ) + { + ERROR("Error populating page"); + goto out; + } - /* Prepare the response */ - rsp.gfn = req.gfn; - rsp.p2mt = req.p2mt; - rsp.vcpu_id = req.vcpu_id; - rsp.flags = req.flags; + /* Prepare the response */ + rsp.gfn = req.gfn; + rsp.p2mt = req.p2mt; + rsp.vcpu_id = req.vcpu_id; + rsp.flags = req.flags; - rc = xenpaging_resume_page(paging, &rsp, 1); - if ( rc != 0 ) - { - ERROR("Error resuming page"); - goto out; + rc = xenpaging_resume_page(paging, &rsp, 1); + if ( rc != 0 ) + { + ERROR("Error resuming page"); + goto out; + } } /* Evict a new page to replace the one we just paged in */ --- xen-unstable.hg-4.1.22694.orig/xen/arch/x86/mm/p2m.c +++ xen-unstable.hg-4.1.22694/xen/arch/x86/mm/p2m.c @@ -2211,12 +2211,15 @@ p2m_remove_page(struct p2m_domain *p2m, P2M_DEBUG("removing gfn=%#lx mfn=%#lx\n", gfn, mfn); - for ( i = 0; i < (1UL << page_order); i++ ) + if ( mfn_valid(_mfn(mfn)) ) { - mfn_return = p2m->get_entry(p2m, gfn + i, &t, &a, p2m_query); - if ( !p2m_is_grant(t) ) - set_gpfn_from_mfn(mfn+i, INVALID_M2P_ENTRY); - ASSERT( !p2m_is_valid(t) || mfn + i == mfn_x(mfn_return) ); + for ( i = 0; i < (1UL << page_order); i++ ) + { + mfn_return = p2m->get_entry(p2m, gfn + i, &t, &a, p2m_query); + if ( !p2m_is_grant(t) ) + set_gpfn_from_mfn(mfn+i, INVALID_M2P_ENTRY); + ASSERT( !p2m_is_valid(t) || mfn + i == mfn_x(mfn_return) ); + } } set_p2m_entry(p2m, gfn, _mfn(INVALID_MFN), page_order, p2m_invalid, p2m->default_access); } @@ -2772,6 +2775,25 @@ int p2m_mem_paging_evict(struct p2m_doma return 0; } +void p2m_mem_paging_drop_page(struct p2m_domain *p2m, unsigned long gfn) +{ + struct vcpu *v = current; + mem_event_request_t req; + struct domain *d = p2m->domain; + + /* Check that there's space on the ring for this request */ + if ( mem_event_check_ring(d) == 0) + { + /* Send release notification to pager */ + memset(&req, 0, sizeof(req)); + req.flags |= MEM_EVENT_FLAG_DROP_PAGE; + req.gfn = gfn; + req.vcpu_id = v->vcpu_id; + + mem_event_put_request(d, &req); + } +} + void p2m_mem_paging_populate(struct p2m_domain *p2m, unsigned long gfn) { struct vcpu *v = current; @@ -2846,13 +2868,16 @@ void p2m_mem_paging_resume(struct p2m_do /* Pull the response off the ring */ mem_event_get_response(d, &rsp); - /* Fix p2m entry */ - mfn = gfn_to_mfn(p2m, rsp.gfn, &p2mt); - p2m_lock(p2m); - set_p2m_entry(p2m, rsp.gfn, mfn, 0, p2m_ram_rw, p2m->default_access); - set_gpfn_from_mfn(mfn_x(mfn), gfn); - audit_p2m(p2m, 1); - p2m_unlock(p2m); + /* Fix p2m entry if the page was not dropped */ + if ( !(rsp.flags & MEM_EVENT_FLAG_DROP_PAGE) ) + { + mfn = gfn_to_mfn(p2m, rsp.gfn, &p2mt); + p2m_lock(p2m); + set_p2m_entry(p2m, rsp.gfn, mfn, 0, p2m_ram_rw, p2m->default_access); + set_gpfn_from_mfn(mfn_x(mfn), rsp.gfn); + audit_p2m(p2m, 1); + p2m_unlock(p2m); + } /* Unpause domain */ if ( rsp.flags & MEM_EVENT_FLAG_VCPU_PAUSED ) --- xen-unstable.hg-4.1.22694.orig/xen/common/memory.c +++ xen-unstable.hg-4.1.22694/xen/common/memory.c @@ -163,6 +163,12 @@ int guest_remove_page(struct domain *d, #ifdef CONFIG_X86 mfn = mfn_x(gfn_to_mfn(p2m_get_hostp2m(d), gmfn, &p2mt)); + if ( unlikely(p2m_is_paging(p2mt)) ) + { + guest_physmap_remove_page(d, gmfn, mfn, 0); + p2m_mem_paging_drop_page(p2m_get_hostp2m(d), gmfn); + return 1; + } #else mfn = gmfn_to_mfn(d, gmfn); #endif --- xen-unstable.hg-4.1.22694.orig/xen/include/asm-x86/p2m.h +++ xen-unstable.hg-4.1.22694/xen/include/asm-x86/p2m.h @@ -511,6 +511,8 @@ int set_shared_p2m_entry(struct p2m_doma int p2m_mem_paging_nominate(struct p2m_domain *p2m, unsigned long gfn); /* Evict a frame */ int p2m_mem_paging_evict(struct p2m_domain *p2m, unsigned long gfn); +/* Tell xenpaging to drop a paged out frame */ +void p2m_mem_paging_drop_page(struct p2m_domain *p2m, unsigned long gfn); /* Start populating a paged out frame */ void p2m_mem_paging_populate(struct p2m_domain *p2m, unsigned long gfn); /* Prepare the p2m for paging a frame in */ @@ -518,6 +520,8 @@ int p2m_mem_paging_prep(struct p2m_domai /* Resume normal operation (in case a domain was paused) */ void p2m_mem_paging_resume(struct p2m_domain *p2m); #else +static inline void p2m_mem_paging_drop_page(struct p2m_domain *p2m, unsigned long gfn) +{ } static inline void p2m_mem_paging_populate(struct p2m_domain *p2m, unsigned long gfn) { } #endif --- xen-unstable.hg-4.1.22694.orig/xen/include/public/mem_event.h +++ xen-unstable.hg-4.1.22694/xen/include/public/mem_event.h @@ -33,6 +33,7 @@ /* Memory event flags */ #define MEM_EVENT_FLAG_VCPU_PAUSED (1 << 0) +#define MEM_EVENT_FLAG_DROP_PAGE (1 << 1) /* Reasons for the memory event request */ #define MEM_EVENT_REASON_UNKNOWN 0 /* typical reason */