Re: [RFC 4/4] mm: Enhance per process reclaim

From: Michael Kerrisk (man-pages)
Date: Wed Apr 03 2013 - 02:16:49 EST

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In reply to: Minchan Kim: "Re: [RFC 4/4] mm: Enhance per process reclaim"
Next in thread: Michael Kerrisk (man-pages): "Re: [RFC 4/4] mm: Enhance per process reclaim"
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Hello Minchan

On Wed, Apr 3, 2013 at 2:23 AM, Minchan Kim <minchan@xxxxxxxxxx> wrote:
> Hey Michael,
>
> On Tue, Apr 02, 2013 at 03:25:25PM +0200, Michael Kerrisk wrote:
>> Minchan,
>>
>> On Mon, Mar 25, 2013 at 7:21 AM, Minchan Kim <minchan@xxxxxxxxxx> wrote:
>> >
>> > Some pages could be shared by several processes. (ex, libc)
>> > In case of that, it's too bad to reclaim them from the beginnig.
>> >
>> > This patch causes VM to keep them on memory until last task
>> > try to reclaim them so shared pages will be reclaimed only if
>> > all of task has gone swapping out.
>> >
>> > This feature doesn't handle non-linear mapping on ramfs because
>> > it's very time-consuming and doesn't make sure of reclaiming and
>> > not common.
>>
>> Against what tree does this patch apply? I've tries various trees,
>> including MMOTM of 26 March, and encounter this error:
>>
>> CC mm/ksm.o
>> mm/ksm.c: In function ‘try_to_unmap_ksm’:
>> mm/ksm.c:1970:32: error: ‘vma’ undeclared (first use in this function)
>> mm/ksm.c:1970:32: note: each undeclared identifier is reported only
>> once for each function it appears in
>> make[1]: *** [mm/ksm.o] Error 1
>> make: *** [mm] Error 2
>
> I did it based on mmotm-2013-03-22-15-21 and you found build problem.
> Could you apply below patch? I will fix up below in next spin.
> Thanks for the testing!

This is getting confusing. Was that a patch on top of the other 4
patches? I assume so. I applied all 5 patches on
mmotm-2013-03-22-15-21, but still get a build error:

mm/memcontrol.c: In function ‘mem_cgroup_move_parent’:
mm/memcontrol.c:3868:2: error: implicit declaration of function
‘isolate_lru_page’ [-Werror=implicit-function-declaration]
mm/memcontrol.c:3892:2: error: implicit declaration of function
‘putback_lru_page’ [-Werror=implicit-function-declaration]
cc1: some warnings being treated as errors
make[1]: *** [mm/memcontrol.o] Error 1
make[1]: *** Waiting for unfinished jobs....
make: *** [mm] Error 2
make: *** Waiting for unfinished jobs....

Cheers,

Michael

> From 0934270618ccd4883d6bb05653c664a385fb9441 Mon Sep 17 00:00:00 2001
> From: Minchan Kim <minchan@xxxxxxxxxx>
> Date: Wed, 3 Apr 2013 09:19:49 +0900
> Subject: [PATCH] fix: compile error for CONFIG_KSM
>
> Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
> ---
> include/linux/rmap.h | 2 ++
> mm/ksm.c | 2 +-
> 2 files changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/rmap.h b/include/linux/rmap.h
> index 6c7d030..7bcf090 100644
> --- a/include/linux/rmap.h
> +++ b/include/linux/rmap.h
> @@ -14,6 +14,8 @@ extern int isolate_lru_page(struct page *page);
> extern void putback_lru_page(struct page *page);
> extern unsigned long reclaim_pages_from_list(struct list_head *page_list,
> struct vm_area_struct *vma);
> +extern unsigned long vma_address(struct page *page,
> + struct vm_area_struct *vma);
>
> /*
> * The anon_vma heads a list of private "related" vmas, to scan if
> diff --git a/mm/ksm.c b/mm/ksm.c
> index 1a90d13..44de936 100644
> --- a/mm/ksm.c
> +++ b/mm/ksm.c
> @@ -1967,7 +1967,7 @@ int try_to_unmap_ksm(struct page *page, enum ttu_flags flags,
>
> if (target_vma) {
> unsigned long address = vma_address(page, target_vma);
> - ret = try_to_unmap_one(page, vma, address, flags);
> + ret = try_to_unmap_one(page, target_vma, address, flags);
> goto out;
> }
> again:
> --
> 1.8.2
>
>>
>> Cheers,
>>
>> Michael
>>
>>
>> > Signed-off-by: Sangseok Lee <sangseok.lee@xxxxxxx>
>> > Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
>> > ---
>> > fs/proc/task_mmu.c | 2 +-
>> > include/linux/ksm.h | 6 ++++--
>> > include/linux/rmap.h | 8 +++++---
>> > mm/ksm.c | 9 +++++++-
>> > mm/memory-failure.c | 2 +-
>> > mm/migrate.c | 6 ++++--
>> > mm/rmap.c | 58 +++++++++++++++++++++++++++++++++++++---------------
>> > mm/vmscan.c | 14 +++++++++++--
>> > 8 files changed, 77 insertions(+), 28 deletions(-)
>> >
>> > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
>> > index c3713a4..7f6aaf5 100644
>> > --- a/fs/proc/task_mmu.c
>> > +++ b/fs/proc/task_mmu.c
>> > @@ -1154,7 +1154,7 @@ cont:
>> > break;
>> > }
>> > pte_unmap_unlock(pte - 1, ptl);
>> > - reclaim_pages_from_list(&page_list);
>> > + reclaim_pages_from_list(&page_list, vma);
>> > if (addr != end)
>> > goto cont;
>> >
>> > diff --git a/include/linux/ksm.h b/include/linux/ksm.h
>> > index 45c9b6a..d8e556b 100644
>> > --- a/include/linux/ksm.h
>> > +++ b/include/linux/ksm.h
>> > @@ -75,7 +75,8 @@ struct page *ksm_might_need_to_copy(struct page *page,
>> >
>> > int page_referenced_ksm(struct page *page,
>> > struct mem_cgroup *memcg, unsigned long *vm_flags);
>> > -int try_to_unmap_ksm(struct page *page, enum ttu_flags flags);
>> > +int try_to_unmap_ksm(struct page *page,
>> > + enum ttu_flags flags, struct vm_area_struct *vma);
>> > int rmap_walk_ksm(struct page *page, int (*rmap_one)(struct page *,
>> > struct vm_area_struct *, unsigned long, void *), void *arg);
>> > void ksm_migrate_page(struct page *newpage, struct page *oldpage);
>> > @@ -115,7 +116,8 @@ static inline int page_referenced_ksm(struct page *page,
>> > return 0;
>> > }
>> >
>> > -static inline int try_to_unmap_ksm(struct page *page, enum ttu_flags flags)
>> > +static inline int try_to_unmap_ksm(struct page *page,
>> > + enum ttu_flags flags, struct vm_area_struct *target_vma)
>> > {
>> > return 0;
>> > }
>> > diff --git a/include/linux/rmap.h b/include/linux/rmap.h
>> > index a24e34e..6c7d030 100644
>> > --- a/include/linux/rmap.h
>> > +++ b/include/linux/rmap.h
>> > @@ -12,7 +12,8 @@
>> >
>> > extern int isolate_lru_page(struct page *page);
>> > extern void putback_lru_page(struct page *page);
>> > -extern unsigned long reclaim_pages_from_list(struct list_head *page_list);
>> > +extern unsigned long reclaim_pages_from_list(struct list_head *page_list,
>> > + struct vm_area_struct *vma);
>> >
>> > /*
>> > * The anon_vma heads a list of private "related" vmas, to scan if
>> > @@ -192,7 +193,8 @@ int page_referenced_one(struct page *, struct vm_area_struct *,
>> >
>> > #define TTU_ACTION(x) ((x) & TTU_ACTION_MASK)
>> >
>> > -int try_to_unmap(struct page *, enum ttu_flags flags);
>> > +int try_to_unmap(struct page *, enum ttu_flags flags,
>> > + struct vm_area_struct *vma);
>> > int try_to_unmap_one(struct page *, struct vm_area_struct *,
>> > unsigned long address, enum ttu_flags flags);
>> >
>> > @@ -259,7 +261,7 @@ static inline int page_referenced(struct page *page, int is_locked,
>> > return 0;
>> > }
>> >
>> > -#define try_to_unmap(page, refs) SWAP_FAIL
>> > +#define try_to_unmap(page, refs, vma) SWAP_FAIL
>> >
>> > static inline int page_mkclean(struct page *page)
>> > {
>> > diff --git a/mm/ksm.c b/mm/ksm.c
>> > index 7f629e4..1a90d13 100644
>> > --- a/mm/ksm.c
>> > +++ b/mm/ksm.c
>> > @@ -1949,7 +1949,8 @@ out:
>> > return referenced;
>> > }
>> >
>> > -int try_to_unmap_ksm(struct page *page, enum ttu_flags flags)
>> > +int try_to_unmap_ksm(struct page *page, enum ttu_flags flags,
>> > + struct vm_area_struct *target_vma)
>> > {
>> > struct stable_node *stable_node;
>> > struct hlist_node *hlist;
>> > @@ -1963,6 +1964,12 @@ int try_to_unmap_ksm(struct page *page, enum ttu_flags flags)
>> > stable_node = page_stable_node(page);
>> > if (!stable_node)
>> > return SWAP_FAIL;
>> > +
>> > + if (target_vma) {
>> > + unsigned long address = vma_address(page, target_vma);
>> > + ret = try_to_unmap_one(page, vma, address, flags);
>> > + goto out;
>> > + }
>> > again:
>> > hlist_for_each_entry(rmap_item, hlist, &stable_node->hlist, hlist) {
>> > struct anon_vma *anon_vma = rmap_item->anon_vma;
>> > diff --git a/mm/memory-failure.c b/mm/memory-failure.c
>> > index ceb0c7f..f3928e4 100644
>> > --- a/mm/memory-failure.c
>> > +++ b/mm/memory-failure.c
>> > @@ -955,7 +955,7 @@ static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
>> > if (hpage != ppage)
>> > lock_page(ppage);
>> >
>> > - ret = try_to_unmap(ppage, ttu);
>> > + ret = try_to_unmap(ppage, ttu, NULL);
>> > if (ret != SWAP_SUCCESS)
>> > printk(KERN_ERR "MCE %#lx: failed to unmap page (mapcount=%d)\n",
>> > pfn, page_mapcount(ppage));
>> > diff --git a/mm/migrate.c b/mm/migrate.c
>> > index 6fa4ebc..aafbc66 100644
>> > --- a/mm/migrate.c
>> > +++ b/mm/migrate.c
>> > @@ -820,7 +820,8 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
>> > }
>> >
>> > /* Establish migration ptes or remove ptes */
>> > - try_to_unmap(page, TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS);
>> > + try_to_unmap(page, TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS,
>> > + NULL);
>> >
>> > skip_unmap:
>> > if (!page_mapped(page))
>> > @@ -947,7 +948,8 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
>> > if (PageAnon(hpage))
>> > anon_vma = page_get_anon_vma(hpage);
>> >
>> > - try_to_unmap(hpage, TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS);
>> > + try_to_unmap(hpage, TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS,
>> > + NULL);
>> >
>> > if (!page_mapped(hpage))
>> > rc = move_to_new_page(new_hpage, hpage, 1, mode);
>> > diff --git a/mm/rmap.c b/mm/rmap.c
>> > index 6280da8..a880f24 100644
>> > --- a/mm/rmap.c
>> > +++ b/mm/rmap.c
>> > @@ -1435,13 +1435,16 @@ bool is_vma_temporary_stack(struct vm_area_struct *vma)
>> >
>> > /**
>> > * try_to_unmap_anon - unmap or unlock anonymous page using the object-based
>> > - * rmap method
>> > + * rmap method if @vma is NULL
>> > * @page: the page to unmap/unlock
>> > * @flags: action and flags
>> > + * @target_vma: vma for unmapping a @page
>> > *
>> > * Find all the mappings of a page using the mapping pointer and the vma chains
>> > * contained in the anon_vma struct it points to.
>> > *
>> > + * If @target_vma isn't NULL, this function unmap a page from the vma
>> > + *
>> > * This function is only called from try_to_unmap/try_to_munlock for
>> > * anonymous pages.
>> > * When called from try_to_munlock(), the mmap_sem of the mm containing the vma
>> > @@ -1449,12 +1452,19 @@ bool is_vma_temporary_stack(struct vm_area_struct *vma)
>> > * vm_flags for that VMA. That should be OK, because that vma shouldn't be
>> > * 'LOCKED.
>> > */
>> > -static int try_to_unmap_anon(struct page *page, enum ttu_flags flags)
>> > +static int try_to_unmap_anon(struct page *page, enum ttu_flags flags,
>> > + struct vm_area_struct *target_vma)
>> > {
>> > + int ret = SWAP_AGAIN;
>> > + unsigned long address;
>> > struct anon_vma *anon_vma;
>> > pgoff_t pgoff;
>> > struct anon_vma_chain *avc;
>> > - int ret = SWAP_AGAIN;
>> > +
>> > + if (target_vma) {
>> > + address = vma_address(page, target_vma);
>> > + return try_to_unmap_one(page, target_vma, address, flags);
>> > + }
>> >
>> > anon_vma = page_lock_anon_vma_read(page);
>> > if (!anon_vma)
>> > @@ -1463,7 +1473,6 @@ static int try_to_unmap_anon(struct page *page, enum ttu_flags flags)
>> > pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
>> > anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
>> > struct vm_area_struct *vma = avc->vma;
>> > - unsigned long address;
>> >
>> > /*
>> > * During exec, a temporary VMA is setup and later moved.
>> > @@ -1491,6 +1500,7 @@ static int try_to_unmap_anon(struct page *page, enum ttu_flags flags)
>> > * try_to_unmap_file - unmap/unlock file page using the object-based rmap method
>> > * @page: the page to unmap/unlock
>> > * @flags: action and flags
>> > + * @target_vma: vma for unmapping @page
>> > *
>> > * Find all the mappings of a page using the mapping pointer and the vma chains
>> > * contained in the address_space struct it points to.
>> > @@ -1502,7 +1512,8 @@ static int try_to_unmap_anon(struct page *page, enum ttu_flags flags)
>> > * vm_flags for that VMA. That should be OK, because that vma shouldn't be
>> > * 'LOCKED.
>> > */
>> > -static int try_to_unmap_file(struct page *page, enum ttu_flags flags)
>> > +static int try_to_unmap_file(struct page *page, enum ttu_flags flags,
>> > + struct vm_area_struct *target_vma)
>> > {
>> > struct address_space *mapping = page->mapping;
>> > pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
>> > @@ -1512,16 +1523,27 @@ static int try_to_unmap_file(struct page *page, enum ttu_flags flags)
>> > unsigned long max_nl_cursor = 0;
>> > unsigned long max_nl_size = 0;
>> > unsigned int mapcount;
>> > + unsigned long address;
>> >
>> > if (PageHuge(page))
>> > pgoff = page->index << compound_order(page);
>> >
>> > mutex_lock(&mapping->i_mmap_mutex);
>> > - vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
>> > - unsigned long address = vma_address(page, vma);
>> > - ret = try_to_unmap_one(page, vma, address, flags);
>> > - if (ret != SWAP_AGAIN || !page_mapped(page))
>> > + if (target_vma) {
>> > + /* We don't handle non-linear vma on ramfs */
>> > + if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
>> > goto out;
>> > +
>> > + address = vma_address(page, target_vma);
>> > + ret = try_to_unmap_one(page, target_vma, address, flags);
>> > + goto out;
>> > + } else {
>> > + vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
>> > + address = vma_address(page, vma);
>> > + ret = try_to_unmap_one(page, vma, address, flags);
>> > + if (ret != SWAP_AGAIN || !page_mapped(page))
>> > + goto out;
>> > + }
>> > }
>> >
>> > if (list_empty(&mapping->i_mmap_nonlinear))
>> > @@ -1602,9 +1624,12 @@ out:
>> > * try_to_unmap - try to remove all page table mappings to a page
>> > * @page: the page to get unmapped
>> > * @flags: action and flags
>> > + * @vma : target vma for reclaim
>> > *
>> > * Tries to remove all the page table entries which are mapping this
>> > * page, used in the pageout path. Caller must hold the page lock.
>> > + * If @vma is not NULL, this function try to remove @page from only @vma
>> > + * without peeking all mapped vma for @page.
>> > * Return values are:
>> > *
>> > * SWAP_SUCCESS - we succeeded in removing all mappings
>> > @@ -1612,7 +1637,8 @@ out:
>> > * SWAP_FAIL - the page is unswappable
>> > * SWAP_MLOCK - page is mlocked.
>> > */
>> > -int try_to_unmap(struct page *page, enum ttu_flags flags)
>> > +int try_to_unmap(struct page *page, enum ttu_flags flags,
>> > + struct vm_area_struct *vma)
>> > {
>> > int ret;
>> >
>> > @@ -1620,11 +1646,11 @@ int try_to_unmap(struct page *page, enum ttu_flags flags)
>> > VM_BUG_ON(!PageHuge(page) && PageTransHuge(page));
>> >
>> > if (unlikely(PageKsm(page)))
>> > - ret = try_to_unmap_ksm(page, flags);
>> > + ret = try_to_unmap_ksm(page, flags, vma);
>> > else if (PageAnon(page))
>> > - ret = try_to_unmap_anon(page, flags);
>> > + ret = try_to_unmap_anon(page, flags, vma);
>> > else
>> > - ret = try_to_unmap_file(page, flags);
>> > + ret = try_to_unmap_file(page, flags, vma);
>> > if (ret != SWAP_MLOCK && !page_mapped(page))
>> > ret = SWAP_SUCCESS;
>> > return ret;
>> > @@ -1650,11 +1676,11 @@ int try_to_munlock(struct page *page)
>> > VM_BUG_ON(!PageLocked(page) || PageLRU(page));
>> >
>> > if (unlikely(PageKsm(page)))
>> > - return try_to_unmap_ksm(page, TTU_MUNLOCK);
>> > + return try_to_unmap_ksm(page, TTU_MUNLOCK, NULL);
>> > else if (PageAnon(page))
>> > - return try_to_unmap_anon(page, TTU_MUNLOCK);
>> > + return try_to_unmap_anon(page, TTU_MUNLOCK, NULL);
>> > else
>> > - return try_to_unmap_file(page, TTU_MUNLOCK);
>> > + return try_to_unmap_file(page, TTU_MUNLOCK, NULL);
>> > }
>> >
>> > void __put_anon_vma(struct anon_vma *anon_vma)
>> > diff --git a/mm/vmscan.c b/mm/vmscan.c
>> > index 367d0f4..df9c4d3 100644
>> > --- a/mm/vmscan.c
>> > +++ b/mm/vmscan.c
>> > @@ -92,6 +92,13 @@ struct scan_control {
>> > * are scanned.
>> > */
>> > nodemask_t *nodemask;
>> > +
>> > + /*
>> > + * Reclaim pages from a vma. If the page is shared by other tasks
>> > + * it is zapped from a vma without reclaim so it ends up remaining
>> > + * on memory until last task zap it.
>> > + */
>> > + struct vm_area_struct *target_vma;
>> > };
>> >
>> > #define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru))
>> > @@ -793,7 +800,8 @@ static unsigned long shrink_page_list(struct list_head *page_list,
>> > * processes. Try to unmap it here.
>> > */
>> > if (page_mapped(page) && mapping) {
>> > - switch (try_to_unmap(page, ttu_flags)) {
>> > + switch (try_to_unmap(page,
>> > + ttu_flags, sc->target_vma)) {
>> > case SWAP_FAIL:
>> > goto activate_locked;
>> > case SWAP_AGAIN:
>> > @@ -1000,13 +1008,15 @@ unsigned long reclaim_clean_pages_from_list(struct zone *zone,
>> > }
>> >
>> > #ifdef CONFIG_PROCESS_RECLAIM
>> > -unsigned long reclaim_pages_from_list(struct list_head *page_list)
>> > +unsigned long reclaim_pages_from_list(struct list_head *page_list,
>> > + struct vm_area_struct *vma)
>> > {
>> > struct scan_control sc = {
>> > .gfp_mask = GFP_KERNEL,
>> > .priority = DEF_PRIORITY,
>> > .may_unmap = 1,
>> > .may_swap = 1,
>> > + .target_vma = vma,
>> > };
>> >
>> > unsigned long nr_reclaimed;
>> > --
>> > 1.8.2
>> >
>> > --
>> > To unsubscribe, send a message with 'unsubscribe linux-mm' in
>> > the body to majordomo@xxxxxxxxxx For more info on Linux MM,
>> > see: http://www.linux-mm.org/ .
>> > Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
>>
>> --
>> To unsubscribe, send a message with 'unsubscribe linux-mm' in
>> the body to majordomo@xxxxxxxxxx For more info on Linux MM,
>> see: http://www.linux-mm.org/ .
>> Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
>
> --
> Kind regards,
> Minchan Kim

--
Michael Kerrisk
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Author of "The Linux Programming Interface"; http://man7.org/tlpi/
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