Re: Merge swap-backed and object-backed inactive lists
> Date: Mon, 2 May 2022 18:39:17 +0200
> From: Martin Pieuchot
>
> Let's simplify the existing logic and use a single list for inactive
> pages. uvmpd_scan_inactive() already does a lot of check if it finds
> a page which is swap-backed. This will be improved in a next change.
So NetBSD did this in 2001. The commit message doesn't say why
though. The simplification is nice and the diff does what it says.
> ok?
ok kettenis@
> Index: uvm/uvm.h
> ===
> RCS file: /cvs/src/sys/uvm/uvm.h,v
> retrieving revision 1.68
> diff -u -p -r1.68 uvm.h
> --- uvm/uvm.h 24 Nov 2020 13:49:09 - 1.68
> +++ uvm/uvm.h 2 May 2022 16:32:16 -
> @@ -53,8 +53,7 @@ struct uvm {
>
> /* vm_page queues */
> struct pglist page_active; /* [Q] allocated pages, in use */
> - struct pglist page_inactive_swp;/* [Q] pages inactive (reclaim/free) */
> - struct pglist page_inactive_obj;/* [Q] pages inactive (reclaim/free) */
> + struct pglist page_inactive;/* [Q] pages inactive (reclaim/free) */
> /* Lock order: pageqlock, then fpageqlock. */
> struct mutex pageqlock; /* [] lock for active/inactive page q */
> struct mutex fpageqlock;/* [] lock for free page q + pdaemon */
> Index: uvm/uvm_map.c
> ===
> RCS file: /cvs/src/sys/uvm/uvm_map.c,v
> retrieving revision 1.290
> diff -u -p -r1.290 uvm_map.c
> --- uvm/uvm_map.c 12 Mar 2022 08:11:07 - 1.290
> +++ uvm/uvm_map.c 2 May 2022 16:32:16 -
> @@ -3281,8 +3281,7 @@ uvm_page_printit(struct vm_page *pg, boo
> (*pr)(" >>> page not found in uvm_pmemrange <<<\n");
> pgl = NULL;
> } else if (pg->pg_flags & PQ_INACTIVE) {
> - pgl = (pg->pg_flags & PQ_SWAPBACKED) ?
> - &uvm.page_inactive_swp : &uvm.page_inactive_obj;
> + pgl = &uvm.page_inactive;
> } else if (pg->pg_flags & PQ_ACTIVE) {
> pgl = &uvm.page_active;
> } else {
> Index: uvm/uvm_page.c
> ===
> RCS file: /cvs/src/sys/uvm/uvm_page.c,v
> retrieving revision 1.164
> diff -u -p -r1.164 uvm_page.c
> --- uvm/uvm_page.c28 Apr 2022 09:59:28 - 1.164
> +++ uvm/uvm_page.c2 May 2022 16:32:16 -
> @@ -185,8 +185,7 @@ uvm_page_init(vaddr_t *kvm_startp, vaddr
>*/
>
> TAILQ_INIT(&uvm.page_active);
> - TAILQ_INIT(&uvm.page_inactive_swp);
> - TAILQ_INIT(&uvm.page_inactive_obj);
> + TAILQ_INIT(&uvm.page_inactive);
> mtx_init(&uvm.pageqlock, IPL_VM);
> mtx_init(&uvm.fpageqlock, IPL_VM);
> uvm_pmr_init();
> @@ -994,10 +993,7 @@ uvm_pageclean(struct vm_page *pg)
> uvmexp.active--;
> }
> if (pg->pg_flags & PQ_INACTIVE) {
> - if (pg->pg_flags & PQ_SWAPBACKED)
> - TAILQ_REMOVE(&uvm.page_inactive_swp, pg, pageq);
> - else
> - TAILQ_REMOVE(&uvm.page_inactive_obj, pg, pageq);
> + TAILQ_REMOVE(&uvm.page_inactive, pg, pageq);
> flags_to_clear |= PQ_INACTIVE;
> uvmexp.inactive--;
> }
> @@ -1253,10 +1249,7 @@ uvm_pagewire(struct vm_page *pg)
> uvmexp.active--;
> }
> if (pg->pg_flags & PQ_INACTIVE) {
> - if (pg->pg_flags & PQ_SWAPBACKED)
> - TAILQ_REMOVE(&uvm.page_inactive_swp, pg, pageq);
> - else
> - TAILQ_REMOVE(&uvm.page_inactive_obj, pg, pageq);
> + TAILQ_REMOVE(&uvm.page_inactive, pg, pageq);
> atomic_clearbits_int(&pg->pg_flags, PQ_INACTIVE);
> uvmexp.inactive--;
> }
> @@ -1304,10 +1297,7 @@ uvm_pagedeactivate(struct vm_page *pg)
> }
> if ((pg->pg_flags & PQ_INACTIVE) == 0) {
> KASSERT(pg->wire_count == 0);
> - if (pg->pg_flags & PQ_SWAPBACKED)
> - TAILQ_INSERT_TAIL(&uvm.page_inactive_swp, pg, pageq);
> - else
> - TAILQ_INSERT_TAIL(&uvm.page_inactive_obj, pg, pageq);
> + TAILQ_INSERT_TAIL(&uvm.page_inactive, pg, pageq);
> atomic_setbits_int(&pg->pg_flags, PQ_INACTIVE);
> uvmexp.inactive++;
> pmap_clear_reference(pg);
> @@ -1335,10 +1325,7 @@ uvm_pageactivate(struct vm_page *pg)
> MUTEX_ASSERT_LOCKED(&uvm.pageqlock);
>
> if (pg->pg_flags & PQ_INACTIVE) {
> - if (pg->pg_flags & PQ_SWAPBACKED)
> - TAILQ_REMOVE(&uvm.page_inactive_swp, pg, pageq);
> - else
> - TAILQ_REMOVE(&uvm.page_inactive_obj, pg, pageq);
> + TAILQ_REMOVE(&uvm.page_inactive, pg, pageq);
> atomic_clearbits_int(&pg->pg_flags, PQ_INACTIVE);
>
Re: Merge swap-backed and object-backed inactive lists
On Mon, 02 May 2022 18:39:17 +0200, Martin Pieuchot wrote: > Let's simplify the existing logic and use a single list for inactive > pages. uvmpd_scan_inactive() already does a lot of check if it finds > a page which is swap-backed. This will be improved in a next change. That looks fine to me. Calling uvmpd_scan_inactive() a single time (instead of up to three times!) seems like a win. - todd
Merge swap-backed and object-backed inactive lists
Let's simplify the existing logic and use a single list for inactive
pages. uvmpd_scan_inactive() already does a lot of check if it finds
a page which is swap-backed. This will be improved in a next change.
ok?
Index: uvm/uvm.h
===
RCS file: /cvs/src/sys/uvm/uvm.h,v
retrieving revision 1.68
diff -u -p -r1.68 uvm.h
--- uvm/uvm.h 24 Nov 2020 13:49:09 - 1.68
+++ uvm/uvm.h 2 May 2022 16:32:16 -
@@ -53,8 +53,7 @@ struct uvm {
/* vm_page queues */
struct pglist page_active; /* [Q] allocated pages, in use */
- struct pglist page_inactive_swp;/* [Q] pages inactive (reclaim/free) */
- struct pglist page_inactive_obj;/* [Q] pages inactive (reclaim/free) */
+ struct pglist page_inactive;/* [Q] pages inactive (reclaim/free) */
/* Lock order: pageqlock, then fpageqlock. */
struct mutex pageqlock; /* [] lock for active/inactive page q */
struct mutex fpageqlock;/* [] lock for free page q + pdaemon */
Index: uvm/uvm_map.c
===
RCS file: /cvs/src/sys/uvm/uvm_map.c,v
retrieving revision 1.290
diff -u -p -r1.290 uvm_map.c
--- uvm/uvm_map.c 12 Mar 2022 08:11:07 - 1.290
+++ uvm/uvm_map.c 2 May 2022 16:32:16 -
@@ -3281,8 +3281,7 @@ uvm_page_printit(struct vm_page *pg, boo
(*pr)(" >>> page not found in uvm_pmemrange <<<\n");
pgl = NULL;
} else if (pg->pg_flags & PQ_INACTIVE) {
- pgl = (pg->pg_flags & PQ_SWAPBACKED) ?
- &uvm.page_inactive_swp : &uvm.page_inactive_obj;
+ pgl = &uvm.page_inactive;
} else if (pg->pg_flags & PQ_ACTIVE) {
pgl = &uvm.page_active;
} else {
Index: uvm/uvm_page.c
===
RCS file: /cvs/src/sys/uvm/uvm_page.c,v
retrieving revision 1.164
diff -u -p -r1.164 uvm_page.c
--- uvm/uvm_page.c 28 Apr 2022 09:59:28 - 1.164
+++ uvm/uvm_page.c 2 May 2022 16:32:16 -
@@ -185,8 +185,7 @@ uvm_page_init(vaddr_t *kvm_startp, vaddr
*/
TAILQ_INIT(&uvm.page_active);
- TAILQ_INIT(&uvm.page_inactive_swp);
- TAILQ_INIT(&uvm.page_inactive_obj);
+ TAILQ_INIT(&uvm.page_inactive);
mtx_init(&uvm.pageqlock, IPL_VM);
mtx_init(&uvm.fpageqlock, IPL_VM);
uvm_pmr_init();
@@ -994,10 +993,7 @@ uvm_pageclean(struct vm_page *pg)
uvmexp.active--;
}
if (pg->pg_flags & PQ_INACTIVE) {
- if (pg->pg_flags & PQ_SWAPBACKED)
- TAILQ_REMOVE(&uvm.page_inactive_swp, pg, pageq);
- else
- TAILQ_REMOVE(&uvm.page_inactive_obj, pg, pageq);
+ TAILQ_REMOVE(&uvm.page_inactive, pg, pageq);
flags_to_clear |= PQ_INACTIVE;
uvmexp.inactive--;
}
@@ -1253,10 +1249,7 @@ uvm_pagewire(struct vm_page *pg)
uvmexp.active--;
}
if (pg->pg_flags & PQ_INACTIVE) {
- if (pg->pg_flags & PQ_SWAPBACKED)
- TAILQ_REMOVE(&uvm.page_inactive_swp, pg, pageq);
- else
- TAILQ_REMOVE(&uvm.page_inactive_obj, pg, pageq);
+ TAILQ_REMOVE(&uvm.page_inactive, pg, pageq);
atomic_clearbits_int(&pg->pg_flags, PQ_INACTIVE);
uvmexp.inactive--;
}
@@ -1304,10 +1297,7 @@ uvm_pagedeactivate(struct vm_page *pg)
}
if ((pg->pg_flags & PQ_INACTIVE) == 0) {
KASSERT(pg->wire_count == 0);
- if (pg->pg_flags & PQ_SWAPBACKED)
- TAILQ_INSERT_TAIL(&uvm.page_inactive_swp, pg, pageq);
- else
- TAILQ_INSERT_TAIL(&uvm.page_inactive_obj, pg, pageq);
+ TAILQ_INSERT_TAIL(&uvm.page_inactive, pg, pageq);
atomic_setbits_int(&pg->pg_flags, PQ_INACTIVE);
uvmexp.inactive++;
pmap_clear_reference(pg);
@@ -1335,10 +1325,7 @@ uvm_pageactivate(struct vm_page *pg)
MUTEX_ASSERT_LOCKED(&uvm.pageqlock);
if (pg->pg_flags & PQ_INACTIVE) {
- if (pg->pg_flags & PQ_SWAPBACKED)
- TAILQ_REMOVE(&uvm.page_inactive_swp, pg, pageq);
- else
- TAILQ_REMOVE(&uvm.page_inactive_obj, pg, pageq);
+ TAILQ_REMOVE(&uvm.page_inactive, pg, pageq);
atomic_clearbits_int(&pg->pg_flags, PQ_INACTIVE);
uvmexp.inactive--;
}
Index: uvm/uvm_pdaemon.c
===
RCS file: /cvs/src/sys/uvm/uvm_pdaemon.c,v
retrieving revision 1.97
diff -u -p -r1.97 uvm_pdaemon.c
--- uvm/uvm_pdaemon.c 30 Apr 2022 1
