From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-we0-f175.google.com (mail-we0-f175.google.com [74.125.82.175]) by kanga.kvack.org (Postfix) with ESMTP id 5BDD66B010D for ; Sun, 23 Mar 2014 10:09:40 -0400 (EDT) Received: by mail-we0-f175.google.com with SMTP id q58so2722644wes.6 for ; Sun, 23 Mar 2014 07:09:39 -0700 (PDT) Received: from mx2.suse.de (cantor2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id jv1si6389112wjc.171.2014.03.23.07.09.38 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Sun, 23 Mar 2014 07:09:38 -0700 (PDT) Date: Sun, 23 Mar 2014 13:29:13 +0100 From: Jan Kara Subject: Re: [PATCH 2/5] vrange: Add purged page detection on setting memory non-volatile Message-ID: <20140323122913.GC2813@quack.suse.cz> References: <1395436655-21670-1-git-send-email-john.stultz@linaro.org> <1395436655-21670-3-git-send-email-john.stultz@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1395436655-21670-3-git-send-email-john.stultz@linaro.org> Sender: owner-linux-mm@kvack.org List-ID: To: John Stultz Cc: LKML , Andrew Morton , Android Kernel Team , Johannes Weiner , Robert Love , Mel Gorman , Hugh Dickins , Dave Hansen , Rik van Riel , Dmitry Adamushko , Neil Brown , Andrea Arcangeli , Mike Hommey , Taras Glek , Jan Kara , KOSAKI Motohiro , Michel Lespinasse , Minchan Kim , "linux-mm@kvack.org" On Fri 21-03-14 14:17:32, John Stultz wrote: > Users of volatile ranges will need to know if memory was discarded. > This patch adds the purged state tracking required to inform userland > when it marks memory as non-volatile that some memory in that range > was purged and needs to be regenerated. > > This simplified implementation which uses some of the logic from > Minchan's earlier efforts, so credit to Minchan for his work. > > Cc: Andrew Morton > Cc: Android Kernel Team > Cc: Johannes Weiner > Cc: Robert Love > Cc: Mel Gorman > Cc: Hugh Dickins > Cc: Dave Hansen > Cc: Rik van Riel > Cc: Dmitry Adamushko > Cc: Neil Brown > Cc: Andrea Arcangeli > Cc: Mike Hommey > Cc: Taras Glek > Cc: Jan Kara > Cc: KOSAKI Motohiro > Cc: Michel Lespinasse > Cc: Minchan Kim > Cc: linux-mm@kvack.org > Signed-off-by: John Stultz Just one minor nit below. Otherwise the patch looks good to me. So you can add Acked-by: Jan Kara Honza > --- > include/linux/swap.h | 15 ++++++++-- > include/linux/swapops.h | 10 +++++++ > include/linux/vrange.h | 3 ++ > mm/vrange.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++++ > 4 files changed, 101 insertions(+), 2 deletions(-) > > diff --git a/include/linux/swap.h b/include/linux/swap.h > index 46ba0c6..18c12f9 100644 > --- a/include/linux/swap.h > +++ b/include/linux/swap.h > @@ -70,8 +70,19 @@ static inline int current_is_kswapd(void) > #define SWP_HWPOISON_NUM 0 > #endif > > -#define MAX_SWAPFILES \ > - ((1 << MAX_SWAPFILES_SHIFT) - SWP_MIGRATION_NUM - SWP_HWPOISON_NUM) > + > +/* > + * Purged volatile range pages > + */ > +#define SWP_VRANGE_PURGED_NUM 1 > +#define SWP_VRANGE_PURGED (MAX_SWAPFILES + SWP_HWPOISON_NUM + SWP_MIGRATION_NUM) > + > + > +#define MAX_SWAPFILES ((1 << MAX_SWAPFILES_SHIFT) \ > + - SWP_MIGRATION_NUM \ > + - SWP_HWPOISON_NUM \ > + - SWP_VRANGE_PURGED_NUM \ > + ) > > /* > * Magic header for a swap area. The first part of the union is > diff --git a/include/linux/swapops.h b/include/linux/swapops.h > index c0f7526..84f43d9 100644 > --- a/include/linux/swapops.h > +++ b/include/linux/swapops.h > @@ -161,6 +161,16 @@ static inline int is_write_migration_entry(swp_entry_t entry) > > #endif > > +static inline swp_entry_t make_vpurged_entry(void) > +{ > + return swp_entry(SWP_VRANGE_PURGED, 0); > +} > + > +static inline int is_vpurged_entry(swp_entry_t entry) > +{ > + return swp_type(entry) == SWP_VRANGE_PURGED; > +} > + > #ifdef CONFIG_MEMORY_FAILURE > /* > * Support for hardware poisoned pages > diff --git a/include/linux/vrange.h b/include/linux/vrange.h > index 6e5331e..986fa85 100644 > --- a/include/linux/vrange.h > +++ b/include/linux/vrange.h > @@ -1,6 +1,9 @@ > #ifndef _LINUX_VRANGE_H > #define _LINUX_VRANGE_H > > +#include > +#include > + > #define VRANGE_NONVOLATILE 0 > #define VRANGE_VOLATILE 1 > #define VRANGE_VALID_FLAGS (0) /* Don't yet support any flags */ > diff --git a/mm/vrange.c b/mm/vrange.c > index 2f8e2ce..1ff3cbd 100644 > --- a/mm/vrange.c > +++ b/mm/vrange.c > @@ -8,6 +8,76 @@ > #include > #include "internal.h" > > +struct vrange_walker { > + struct vm_area_struct *vma; > + int page_was_purged; > +}; > + > + > +/** > + * vrange_check_purged_pte - Checks ptes for purged pages > + * > + * Iterates over the ptes in the pmd checking if they have > + * purged swap entries. > + * > + * Sets the vrange_walker.pages_purged to 1 if any were purged. ^^^ page_was_purged > + */ > +static int vrange_check_purged_pte(pmd_t *pmd, unsigned long addr, > + unsigned long end, struct mm_walk *walk) > +{ > + struct vrange_walker *vw = walk->private; > + pte_t *pte; > + spinlock_t *ptl; > + > + if (pmd_trans_huge(*pmd)) > + return 0; > + if (pmd_trans_unstable(pmd)) > + return 0; > + > + pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); > + for (; addr != end; pte++, addr += PAGE_SIZE) { > + if (!pte_present(*pte)) { > + swp_entry_t vrange_entry = pte_to_swp_entry(*pte); > + > + if (unlikely(is_vpurged_entry(vrange_entry))) { > + vw->page_was_purged = 1; > + break; > + } > + } > + } > + pte_unmap_unlock(pte - 1, ptl); > + cond_resched(); > + > + return 0; > +} > + > + > +/** > + * vrange_check_purged - Sets up a mm_walk to check for purged pages > + * > + * Sets up and calls wa_page_range() to check for purge pages. > + * > + * Returns 1 if pages in the range were purged, 0 otherwise. > + */ > +static int vrange_check_purged(struct mm_struct *mm, > + struct vm_area_struct *vma, > + unsigned long start, > + unsigned long end) > +{ > + struct vrange_walker vw; > + struct mm_walk vrange_walk = { > + .pmd_entry = vrange_check_purged_pte, > + .mm = vma->vm_mm, > + .private = &vw, > + }; > + vw.page_was_purged = 0; > + vw.vma = vma; > + > + walk_page_range(start, end, &vrange_walk); > + > + return vw.page_was_purged; > + > +} > > /** > * do_vrange - Marks or clears VMAs in the range (start-end) as VM_VOLATILE > @@ -106,6 +176,11 @@ success: > vma = prev->vm_next; > } > out: > + if (count && (mode == VRANGE_NONVOLATILE)) > + *purged = vrange_check_purged(mm, vma, > + orig_start, > + orig_start+count); > + > up_read(&mm->mmap_sem); > > /* report bytes successfully marked, even if we're exiting on error */ > -- > 1.8.3.2 > -- Jan Kara SUSE Labs, CR -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752409AbaCWOJ5 (ORCPT ); Sun, 23 Mar 2014 10:09:57 -0400 Received: from cantor2.suse.de ([195.135.220.15]:42154 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752284AbaCWOJj (ORCPT ); Sun, 23 Mar 2014 10:09:39 -0400 Date: Sun, 23 Mar 2014 13:29:13 +0100 From: Jan Kara To: John Stultz Cc: LKML , Andrew Morton , Android Kernel Team , Johannes Weiner , Robert Love , Mel Gorman , Hugh Dickins , Dave Hansen , Rik van Riel , Dmitry Adamushko , Neil Brown , Andrea Arcangeli , Mike Hommey , Taras Glek , Jan Kara , KOSAKI Motohiro , Michel Lespinasse , Minchan Kim , "linux-mm@kvack.org" Subject: Re: [PATCH 2/5] vrange: Add purged page detection on setting memory non-volatile Message-ID: <20140323122913.GC2813@quack.suse.cz> References: <1395436655-21670-1-git-send-email-john.stultz@linaro.org> <1395436655-21670-3-git-send-email-john.stultz@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1395436655-21670-3-git-send-email-john.stultz@linaro.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 21-03-14 14:17:32, John Stultz wrote: > Users of volatile ranges will need to know if memory was discarded. > This patch adds the purged state tracking required to inform userland > when it marks memory as non-volatile that some memory in that range > was purged and needs to be regenerated. > > This simplified implementation which uses some of the logic from > Minchan's earlier efforts, so credit to Minchan for his work. > > Cc: Andrew Morton > Cc: Android Kernel Team > Cc: Johannes Weiner > Cc: Robert Love > Cc: Mel Gorman > Cc: Hugh Dickins > Cc: Dave Hansen > Cc: Rik van Riel > Cc: Dmitry Adamushko > Cc: Neil Brown > Cc: Andrea Arcangeli > Cc: Mike Hommey > Cc: Taras Glek > Cc: Jan Kara > Cc: KOSAKI Motohiro > Cc: Michel Lespinasse > Cc: Minchan Kim > Cc: linux-mm@kvack.org > Signed-off-by: John Stultz Just one minor nit below. Otherwise the patch looks good to me. So you can add Acked-by: Jan Kara Honza > --- > include/linux/swap.h | 15 ++++++++-- > include/linux/swapops.h | 10 +++++++ > include/linux/vrange.h | 3 ++ > mm/vrange.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++++ > 4 files changed, 101 insertions(+), 2 deletions(-) > > diff --git a/include/linux/swap.h b/include/linux/swap.h > index 46ba0c6..18c12f9 100644 > --- a/include/linux/swap.h > +++ b/include/linux/swap.h > @@ -70,8 +70,19 @@ static inline int current_is_kswapd(void) > #define SWP_HWPOISON_NUM 0 > #endif > > -#define MAX_SWAPFILES \ > - ((1 << MAX_SWAPFILES_SHIFT) - SWP_MIGRATION_NUM - SWP_HWPOISON_NUM) > + > +/* > + * Purged volatile range pages > + */ > +#define SWP_VRANGE_PURGED_NUM 1 > +#define SWP_VRANGE_PURGED (MAX_SWAPFILES + SWP_HWPOISON_NUM + SWP_MIGRATION_NUM) > + > + > +#define MAX_SWAPFILES ((1 << MAX_SWAPFILES_SHIFT) \ > + - SWP_MIGRATION_NUM \ > + - SWP_HWPOISON_NUM \ > + - SWP_VRANGE_PURGED_NUM \ > + ) > > /* > * Magic header for a swap area. The first part of the union is > diff --git a/include/linux/swapops.h b/include/linux/swapops.h > index c0f7526..84f43d9 100644 > --- a/include/linux/swapops.h > +++ b/include/linux/swapops.h > @@ -161,6 +161,16 @@ static inline int is_write_migration_entry(swp_entry_t entry) > > #endif > > +static inline swp_entry_t make_vpurged_entry(void) > +{ > + return swp_entry(SWP_VRANGE_PURGED, 0); > +} > + > +static inline int is_vpurged_entry(swp_entry_t entry) > +{ > + return swp_type(entry) == SWP_VRANGE_PURGED; > +} > + > #ifdef CONFIG_MEMORY_FAILURE > /* > * Support for hardware poisoned pages > diff --git a/include/linux/vrange.h b/include/linux/vrange.h > index 6e5331e..986fa85 100644 > --- a/include/linux/vrange.h > +++ b/include/linux/vrange.h > @@ -1,6 +1,9 @@ > #ifndef _LINUX_VRANGE_H > #define _LINUX_VRANGE_H > > +#include > +#include > + > #define VRANGE_NONVOLATILE 0 > #define VRANGE_VOLATILE 1 > #define VRANGE_VALID_FLAGS (0) /* Don't yet support any flags */ > diff --git a/mm/vrange.c b/mm/vrange.c > index 2f8e2ce..1ff3cbd 100644 > --- a/mm/vrange.c > +++ b/mm/vrange.c > @@ -8,6 +8,76 @@ > #include > #include "internal.h" > > +struct vrange_walker { > + struct vm_area_struct *vma; > + int page_was_purged; > +}; > + > + > +/** > + * vrange_check_purged_pte - Checks ptes for purged pages > + * > + * Iterates over the ptes in the pmd checking if they have > + * purged swap entries. > + * > + * Sets the vrange_walker.pages_purged to 1 if any were purged. ^^^ page_was_purged > + */ > +static int vrange_check_purged_pte(pmd_t *pmd, unsigned long addr, > + unsigned long end, struct mm_walk *walk) > +{ > + struct vrange_walker *vw = walk->private; > + pte_t *pte; > + spinlock_t *ptl; > + > + if (pmd_trans_huge(*pmd)) > + return 0; > + if (pmd_trans_unstable(pmd)) > + return 0; > + > + pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); > + for (; addr != end; pte++, addr += PAGE_SIZE) { > + if (!pte_present(*pte)) { > + swp_entry_t vrange_entry = pte_to_swp_entry(*pte); > + > + if (unlikely(is_vpurged_entry(vrange_entry))) { > + vw->page_was_purged = 1; > + break; > + } > + } > + } > + pte_unmap_unlock(pte - 1, ptl); > + cond_resched(); > + > + return 0; > +} > + > + > +/** > + * vrange_check_purged - Sets up a mm_walk to check for purged pages > + * > + * Sets up and calls wa_page_range() to check for purge pages. > + * > + * Returns 1 if pages in the range were purged, 0 otherwise. > + */ > +static int vrange_check_purged(struct mm_struct *mm, > + struct vm_area_struct *vma, > + unsigned long start, > + unsigned long end) > +{ > + struct vrange_walker vw; > + struct mm_walk vrange_walk = { > + .pmd_entry = vrange_check_purged_pte, > + .mm = vma->vm_mm, > + .private = &vw, > + }; > + vw.page_was_purged = 0; > + vw.vma = vma; > + > + walk_page_range(start, end, &vrange_walk); > + > + return vw.page_was_purged; > + > +} > > /** > * do_vrange - Marks or clears VMAs in the range (start-end) as VM_VOLATILE > @@ -106,6 +176,11 @@ success: > vma = prev->vm_next; > } > out: > + if (count && (mode == VRANGE_NONVOLATILE)) > + *purged = vrange_check_purged(mm, vma, > + orig_start, > + orig_start+count); > + > up_read(&mm->mmap_sem); > > /* report bytes successfully marked, even if we're exiting on error */ > -- > 1.8.3.2 > -- Jan Kara SUSE Labs, CR