| Message ID | 20190916101803.30726-14-jarkko.sakkinen@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Fixes and updates for v23 | expand |
On Mon, Sep 16, 2019 at 01:17:59PM +0300, Jarkko Sakkinen wrote: > Make sgx_reclaim_evict() idempotennt and rename it to sgx_can_reclaim() and > set SGX_ENCL_PAGE_RECLAIMED in the call site. > > Cc: Sean Christopherson <sean.j.christopherson@intel.com> > Cc: Shay Katz-zamir <shay.katz-zamir@intel.com> > Cc: Serge Ayoun <serge.ayoun@intel.com> > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> > --- > arch/x86/kernel/cpu/sgx/reclaim.c | 32 +++++++++++++++++-------------- > 1 file changed, 18 insertions(+), 14 deletions(-) > > diff --git a/arch/x86/kernel/cpu/sgx/reclaim.c b/arch/x86/kernel/cpu/sgx/reclaim.c > index 5a4d44dd02d7..cc3155b61513 100644 > --- a/arch/x86/kernel/cpu/sgx/reclaim.c > +++ b/arch/x86/kernel/cpu/sgx/reclaim.c > @@ -121,7 +121,19 @@ void sgx_mark_page_reclaimable(struct sgx_epc_page *page) > spin_unlock(&sgx_active_page_list_lock); > } > > -static bool sgx_reclaimer_evict(struct sgx_epc_page *epc_page) > +/** > + * sgx_can_reclaim() - Filter out the pages that should not be reclaimed > + * @epc_page: a candidate EPC page > + * > + * Do not reclaim this page if it has been recently accessed by any mm_struct > + * *and* if the enclave is still alive. No need to take the enclave's lock, > + * worst case scenario reclaiming pages from a dead enclave is delayed slightly. > + * A live enclave with a recently accessed page is more common and avoiding lock > + * contention in that case is a boon to performance. > + * > + * Return: true if the page should be reclaimed > + */ > +static bool sgx_can_reclaim(struct sgx_epc_page *epc_page) > { > struct sgx_encl_page *page = epc_page->owner; > struct sgx_encl *encl = page->encl; > @@ -147,21 +159,9 @@ static bool sgx_reclaimer_evict(struct sgx_epc_page *epc_page) > > srcu_read_unlock(&encl->srcu, idx); > > - /* > - * Do not reclaim this page if it has been recently accessed by any > - * mm_struct *and* if the enclave is still alive. No need to take > - * the enclave's lock, worst case scenario reclaiming pages from a > - * dead enclave is delayed slightly. A live enclave with a recently > - * accessed page is more common and avoiding lock contention in that > - * case is a boon to performance. > - */ > if (!ret && !(atomic_read(&encl->flags) & SGX_ENCL_DEAD)) > return false; > > - mutex_lock(&encl->lock); > - page->desc |= SGX_ENCL_PAGE_RECLAIMED; > - mutex_unlock(&encl->lock); > - > return true; > } > > @@ -405,8 +405,12 @@ void sgx_reclaim_pages(void) > epc_page = chunk[i]; > encl_page = epc_page->owner; > > - if (sgx_reclaimer_evict(epc_page)) > + if (sgx_can_reclaim(epc_page)) { > + mutex_lock(&encl_page->encl->lock); > + encl_page->desc |= SGX_ENCL_PAGE_RECLAIMED; If we move setting SGX_ENCL_PAGE_RECLAIMED here, then we should also move the clearing (currently in sgx_encl_ewb()) into the loop that calls sgx_reclaimer_write(). That would also fix the issue of SGX_ENCL_PAGE_RECLAIMED being left set when the enclave is dead. > + mutex_unlock(&encl_page->encl->lock); > continue; > + } > > kref_put(&encl_page->encl->refcount, sgx_encl_release); > > -- > 2.20.1 >
On Mon, Sep 16, 2019 at 01:17:59PM +0300, Jarkko Sakkinen wrote: > Make sgx_reclaim_evict() idempotennt and rename it to sgx_can_reclaim() and > set SGX_ENCL_PAGE_RECLAIMED in the call site. > > Cc: Sean Christopherson <sean.j.christopherson@intel.com> > Cc: Shay Katz-zamir <shay.katz-zamir@intel.com> > Cc: Serge Ayoun <serge.ayoun@intel.com> > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> > --- > arch/x86/kernel/cpu/sgx/reclaim.c | 32 +++++++++++++++++-------------- > 1 file changed, 18 insertions(+), 14 deletions(-) > > diff --git a/arch/x86/kernel/cpu/sgx/reclaim.c b/arch/x86/kernel/cpu/sgx/reclaim.c > index 5a4d44dd02d7..cc3155b61513 100644 > --- a/arch/x86/kernel/cpu/sgx/reclaim.c > +++ b/arch/x86/kernel/cpu/sgx/reclaim.c > @@ -121,7 +121,19 @@ void sgx_mark_page_reclaimable(struct sgx_epc_page *page) > spin_unlock(&sgx_active_page_list_lock); > } > > -static bool sgx_reclaimer_evict(struct sgx_epc_page *epc_page) > +/** > + * sgx_can_reclaim() - Filter out the pages that should not be reclaimed > + * @epc_page: a candidate EPC page > + * > + * Do not reclaim this page if it has been recently accessed by any mm_struct > + * *and* if the enclave is still alive. No need to take the enclave's lock, > + * worst case scenario reclaiming pages from a dead enclave is delayed slightly. > + * A live enclave with a recently accessed page is more common and avoiding lock > + * contention in that case is a boon to performance. > + * > + * Return: true if the page should be reclaimed > + */ > +static bool sgx_can_reclaim(struct sgx_epc_page *epc_page) Belated thought. The param can be 'struct sgx_encl_page *encl_page'. The caller already has the encl_page, and the function only uses the epc_page to retrieve the encl_page.
On Wed, Sep 25, 2019 at 11:28:27AM -0700, Sean Christopherson wrote: > On Mon, Sep 16, 2019 at 01:17:59PM +0300, Jarkko Sakkinen wrote: > > Make sgx_reclaim_evict() idempotennt and rename it to sgx_can_reclaim() and > > set SGX_ENCL_PAGE_RECLAIMED in the call site. > > > > Cc: Sean Christopherson <sean.j.christopherson@intel.com> > > Cc: Shay Katz-zamir <shay.katz-zamir@intel.com> > > Cc: Serge Ayoun <serge.ayoun@intel.com> > > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> > > --- > > arch/x86/kernel/cpu/sgx/reclaim.c | 32 +++++++++++++++++-------------- > > 1 file changed, 18 insertions(+), 14 deletions(-) > > > > diff --git a/arch/x86/kernel/cpu/sgx/reclaim.c b/arch/x86/kernel/cpu/sgx/reclaim.c > > index 5a4d44dd02d7..cc3155b61513 100644 > > --- a/arch/x86/kernel/cpu/sgx/reclaim.c > > +++ b/arch/x86/kernel/cpu/sgx/reclaim.c > > @@ -121,7 +121,19 @@ void sgx_mark_page_reclaimable(struct sgx_epc_page *page) > > spin_unlock(&sgx_active_page_list_lock); > > } > > > > -static bool sgx_reclaimer_evict(struct sgx_epc_page *epc_page) > > +/** > > + * sgx_can_reclaim() - Filter out the pages that should not be reclaimed > > + * @epc_page: a candidate EPC page > > + * > > + * Do not reclaim this page if it has been recently accessed by any mm_struct > > + * *and* if the enclave is still alive. No need to take the enclave's lock, > > + * worst case scenario reclaiming pages from a dead enclave is delayed slightly. > > + * A live enclave with a recently accessed page is more common and avoiding lock > > + * contention in that case is a boon to performance. > > + * > > + * Return: true if the page should be reclaimed > > + */ > > +static bool sgx_can_reclaim(struct sgx_epc_page *epc_page) > > Belated thought. The param can be 'struct sgx_encl_page *encl_page'. The > caller already has the encl_page, and the function only uses the epc_page > to retrieve the encl_page. I used sgx_reclaimer_age() for the function when I merged. Agree that the function name was not right because it is not a pure query but also changes state. /Jarkko
diff --git a/arch/x86/kernel/cpu/sgx/reclaim.c b/arch/x86/kernel/cpu/sgx/reclaim.c index 5a4d44dd02d7..cc3155b61513 100644 --- a/arch/x86/kernel/cpu/sgx/reclaim.c +++ b/arch/x86/kernel/cpu/sgx/reclaim.c @@ -121,7 +121,19 @@ void sgx_mark_page_reclaimable(struct sgx_epc_page *page) spin_unlock(&sgx_active_page_list_lock); } -static bool sgx_reclaimer_evict(struct sgx_epc_page *epc_page) +/** + * sgx_can_reclaim() - Filter out the pages that should not be reclaimed + * @epc_page: a candidate EPC page + * + * Do not reclaim this page if it has been recently accessed by any mm_struct + * *and* if the enclave is still alive. No need to take the enclave's lock, + * worst case scenario reclaiming pages from a dead enclave is delayed slightly. + * A live enclave with a recently accessed page is more common and avoiding lock + * contention in that case is a boon to performance. + * + * Return: true if the page should be reclaimed + */ +static bool sgx_can_reclaim(struct sgx_epc_page *epc_page) { struct sgx_encl_page *page = epc_page->owner; struct sgx_encl *encl = page->encl; @@ -147,21 +159,9 @@ static bool sgx_reclaimer_evict(struct sgx_epc_page *epc_page) srcu_read_unlock(&encl->srcu, idx); - /* - * Do not reclaim this page if it has been recently accessed by any - * mm_struct *and* if the enclave is still alive. No need to take - * the enclave's lock, worst case scenario reclaiming pages from a - * dead enclave is delayed slightly. A live enclave with a recently - * accessed page is more common and avoiding lock contention in that - * case is a boon to performance. - */ if (!ret && !(atomic_read(&encl->flags) & SGX_ENCL_DEAD)) return false; - mutex_lock(&encl->lock); - page->desc |= SGX_ENCL_PAGE_RECLAIMED; - mutex_unlock(&encl->lock); - return true; } @@ -405,8 +405,12 @@ void sgx_reclaim_pages(void) epc_page = chunk[i]; encl_page = epc_page->owner; - if (sgx_reclaimer_evict(epc_page)) + if (sgx_can_reclaim(epc_page)) { + mutex_lock(&encl_page->encl->lock); + encl_page->desc |= SGX_ENCL_PAGE_RECLAIMED; + mutex_unlock(&encl_page->encl->lock); continue; + } kref_put(&encl_page->encl->refcount, sgx_encl_release);
Make sgx_reclaim_evict() idempotennt and rename it to sgx_can_reclaim() and set SGX_ENCL_PAGE_RECLAIMED in the call site. Cc: Sean Christopherson <sean.j.christopherson@intel.com> Cc: Shay Katz-zamir <shay.katz-zamir@intel.com> Cc: Serge Ayoun <serge.ayoun@intel.com> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> --- arch/x86/kernel/cpu/sgx/reclaim.c | 32 +++++++++++++++++-------------- 1 file changed, 18 insertions(+), 14 deletions(-)