| Message ID | 20230413104034.1086717-4-yosryahmed@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Ignore non-LRU-based reclaim in memcg reclaim | expand |
On 13.04.23 12:40, Yosry Ahmed wrote: > During reclaim, we keep track of pages reclaimed from other means than > LRU-based reclaim through scan_control->reclaim_state->reclaimed_slab, > which we stash a pointer to in current task_struct. > > However, we keep track of more than just reclaimed slab pages through > this. We also use it for clean file pages dropped through pruned inodes, > and xfs buffer pages freed. Rename reclaimed_slab to reclaimed, and add Would "reclaimed_non_lru" be more expressive? Then, mm_account_reclaimed_pages() -> mm_account_non_lru_reclaimed_pages() Apart from that LGTM.
On Thu, Apr 13, 2023 at 4:21 AM David Hildenbrand <david@redhat.com> wrote: > > On 13.04.23 12:40, Yosry Ahmed wrote: > > During reclaim, we keep track of pages reclaimed from other means than > > LRU-based reclaim through scan_control->reclaim_state->reclaimed_slab, > > which we stash a pointer to in current task_struct. > > > > However, we keep track of more than just reclaimed slab pages through > > this. We also use it for clean file pages dropped through pruned inodes, > > and xfs buffer pages freed. Rename reclaimed_slab to reclaimed, and add > > Would "reclaimed_non_lru" be more expressive? Then, > > mm_account_reclaimed_pages() -> mm_account_non_lru_reclaimed_pages() > > > Apart from that LGTM. Thanks! I suck at naming things. If you think "reclaimed_non_lru" is better, then we can do that. FWIW mm_account_reclaimed_pages() was taken from a suggestion from Dave Chinner. My initial version had a terrible name: report_freed_pages(), so I am happy with whatever you see fit. Should I re-spin for this or can we change it in place? > > -- > Thanks, > > David / dhildenb >
On 13.04.23 13:29, Yosry Ahmed wrote: > On Thu, Apr 13, 2023 at 4:21 AM David Hildenbrand <david@redhat.com> wrote: >> >> On 13.04.23 12:40, Yosry Ahmed wrote: >>> During reclaim, we keep track of pages reclaimed from other means than >>> LRU-based reclaim through scan_control->reclaim_state->reclaimed_slab, >>> which we stash a pointer to in current task_struct. >>> >>> However, we keep track of more than just reclaimed slab pages through >>> this. We also use it for clean file pages dropped through pruned inodes, >>> and xfs buffer pages freed. Rename reclaimed_slab to reclaimed, and add >> >> Would "reclaimed_non_lru" be more expressive? Then, >> >> mm_account_reclaimed_pages() -> mm_account_non_lru_reclaimed_pages() >> >> >> Apart from that LGTM. > > Thanks! > > I suck at naming things. If you think "reclaimed_non_lru" is better, > then we can do that. FWIW mm_account_reclaimed_pages() was taken from > a suggestion from Dave Chinner. My initial version had a terrible > name: report_freed_pages(), so I am happy with whatever you see fit. > > Should I re-spin for this or can we change it in place? Respin would be good, but maybe wait a bit more on other comments. I'm bad at naming things as well :)
On Thu, Apr 13, 2023 at 04:29:43AM -0700, Yosry Ahmed wrote: > On Thu, Apr 13, 2023 at 4:21 AM David Hildenbrand <david@redhat.com> wrote: > > > > On 13.04.23 12:40, Yosry Ahmed wrote: > > > During reclaim, we keep track of pages reclaimed from other means than > > > LRU-based reclaim through scan_control->reclaim_state->reclaimed_slab, > > > which we stash a pointer to in current task_struct. > > > > > > However, we keep track of more than just reclaimed slab pages through > > > this. We also use it for clean file pages dropped through pruned inodes, > > > and xfs buffer pages freed. Rename reclaimed_slab to reclaimed, and add > > > > Would "reclaimed_non_lru" be more expressive? Then, > > > > mm_account_reclaimed_pages() -> mm_account_non_lru_reclaimed_pages() > > > > > > Apart from that LGTM. > > Thanks! > > I suck at naming things. If you think "reclaimed_non_lru" is better, > then we can do that. FWIW mm_account_reclaimed_pages() was taken from > a suggestion from Dave Chinner. My initial version had a terrible > name: report_freed_pages(), so I am happy with whatever you see fit. > > Should I re-spin for this or can we change it in place? I don't care for the noise all the bikeshed painting has generated for a simple change like this. If it's a fix for a bug, and the naming is good enough, just merge it already, ok? -Dave.
On Thu, Apr 13, 2023 at 2:01 PM Dave Chinner <david@fromorbit.com> wrote: > > On Thu, Apr 13, 2023 at 04:29:43AM -0700, Yosry Ahmed wrote: > > On Thu, Apr 13, 2023 at 4:21 AM David Hildenbrand <david@redhat.com> wrote: > > > > > > On 13.04.23 12:40, Yosry Ahmed wrote: > > > > During reclaim, we keep track of pages reclaimed from other means than > > > > LRU-based reclaim through scan_control->reclaim_state->reclaimed_slab, > > > > which we stash a pointer to in current task_struct. > > > > > > > > However, we keep track of more than just reclaimed slab pages through > > > > this. We also use it for clean file pages dropped through pruned inodes, > > > > and xfs buffer pages freed. Rename reclaimed_slab to reclaimed, and add > > > > > > Would "reclaimed_non_lru" be more expressive? Then, > > > > > > mm_account_reclaimed_pages() -> mm_account_non_lru_reclaimed_pages() > > > > > > > > > Apart from that LGTM. > > > > Thanks! > > > > I suck at naming things. If you think "reclaimed_non_lru" is better, > > then we can do that. FWIW mm_account_reclaimed_pages() was taken from > > a suggestion from Dave Chinner. My initial version had a terrible > > name: report_freed_pages(), so I am happy with whatever you see fit. > > > > Should I re-spin for this or can we change it in place? > > I don't care for the noise all the bikeshed painting has generated > for a simple change like this. If it's a fix for a bug, and the > naming is good enough, just merge it already, ok? Sorry for all the noise. I think this version is in good enough shape. Andrew, could you please replace v4 with this v6 without patch 2 as multiple people pointed out that it is unneeded? Sorry for the hassle. > > -Dave. > -- > Dave Chinner > david@fromorbit.com
On Thu 13-04-23 10:40:34, Yosry Ahmed wrote: > During reclaim, we keep track of pages reclaimed from other means than > LRU-based reclaim through scan_control->reclaim_state->reclaimed_slab, > which we stash a pointer to in current task_struct. > > However, we keep track of more than just reclaimed slab pages through > this. We also use it for clean file pages dropped through pruned inodes, > and xfs buffer pages freed. Rename reclaimed_slab to reclaimed, and add > a helper function that wraps updating it through current, so that future > changes to this logic are contained within include/linux/swap.h. > > Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Acked-by: Michal Hocko <mhocko@suse.com>
On Thu, 13 Apr 2023 14:38:03 -0700 Yosry Ahmed <yosryahmed@google.com> wrote: > > > I suck at naming things. If you think "reclaimed_non_lru" is better, > > > then we can do that. FWIW mm_account_reclaimed_pages() was taken from > > > a suggestion from Dave Chinner. My initial version had a terrible > > > name: report_freed_pages(), so I am happy with whatever you see fit. > > > > > > Should I re-spin for this or can we change it in place? > > > > I don't care for the noise all the bikeshed painting has generated > > for a simple change like this. If it's a fix for a bug, and the > > naming is good enough, just merge it already, ok? > > Sorry for all the noise. I think this version is in good enough shape. > > Andrew, could you please replace v4 with this v6 without patch 2 as > multiple people pointed out that it is unneeded? Sorry for the hassle. I like patch 2! mm.git presently has the v6 series. All of it ;)
On Fri, Apr 14, 2023 at 2:47 PM Andrew Morton <akpm@linux-foundation.org> wrote: > > On Thu, 13 Apr 2023 14:38:03 -0700 Yosry Ahmed <yosryahmed@google.com> wrote: > > > > > I suck at naming things. If you think "reclaimed_non_lru" is better, > > > > then we can do that. FWIW mm_account_reclaimed_pages() was taken from > > > > a suggestion from Dave Chinner. My initial version had a terrible > > > > name: report_freed_pages(), so I am happy with whatever you see fit. > > > > > > > > Should I re-spin for this or can we change it in place? > > > > > > I don't care for the noise all the bikeshed painting has generated > > > for a simple change like this. If it's a fix for a bug, and the > > > naming is good enough, just merge it already, ok? > > > > Sorry for all the noise. I think this version is in good enough shape. > > > > Andrew, could you please replace v4 with this v6 without patch 2 as > > multiple people pointed out that it is unneeded? Sorry for the hassle. > > I like patch 2! > > mm.git presently has the v6 series. All of it ;) Thanks Andrew :)
diff --git a/fs/inode.c b/fs/inode.c index 4558dc2f1355..e60fcc41faf1 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -864,8 +864,7 @@ static enum lru_status inode_lru_isolate(struct list_head *item, __count_vm_events(KSWAPD_INODESTEAL, reap); else __count_vm_events(PGINODESTEAL, reap); - if (current->reclaim_state) - current->reclaim_state->reclaimed_slab += reap; + mm_account_reclaimed_pages(reap); } iput(inode); spin_lock(lru_lock); diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c index 54c774af6e1c..15d1e5a7c2d3 100644 --- a/fs/xfs/xfs_buf.c +++ b/fs/xfs/xfs_buf.c @@ -286,8 +286,7 @@ xfs_buf_free_pages( if (bp->b_pages[i]) __free_page(bp->b_pages[i]); } - if (current->reclaim_state) - current->reclaim_state->reclaimed_slab += bp->b_page_count; + mm_account_reclaimed_pages(bp->b_page_count); if (bp->b_pages != bp->b_page_array) kmem_free(bp->b_pages); diff --git a/include/linux/swap.h b/include/linux/swap.h index 209a425739a9..e131ac155fb9 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -153,13 +153,28 @@ union swap_header { * memory reclaim */ struct reclaim_state { - unsigned long reclaimed_slab; + /* pages reclaimed outside of LRU-based reclaim */ + unsigned long reclaimed; #ifdef CONFIG_LRU_GEN /* per-thread mm walk data */ struct lru_gen_mm_walk *mm_walk; #endif }; +/* + * mm_account_reclaimed_pages(): account reclaimed pages outside of LRU-based + * reclaim + * @pages: number of pages reclaimed + * + * If the current process is undergoing a reclaim operation, increment the + * number of reclaimed pages by @pages. + */ +static inline void mm_account_reclaimed_pages(unsigned long pages) +{ + if (current->reclaim_state) + current->reclaim_state->reclaimed += pages; +} + #ifdef __KERNEL__ struct address_space; diff --git a/mm/slab.c b/mm/slab.c index dabc2a671fc6..64bf1de817b2 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -1392,8 +1392,7 @@ static void kmem_freepages(struct kmem_cache *cachep, struct slab *slab) smp_wmb(); __folio_clear_slab(folio); - if (current->reclaim_state) - current->reclaim_state->reclaimed_slab += 1 << order; + mm_account_reclaimed_pages(1 << order); unaccount_slab(slab, order, cachep); __free_pages(&folio->page, order); } diff --git a/mm/slob.c b/mm/slob.c index fe567fcfa3a3..79cc8680c973 100644 --- a/mm/slob.c +++ b/mm/slob.c @@ -61,7 +61,7 @@ #include <linux/slab.h> #include <linux/mm.h> -#include <linux/swap.h> /* struct reclaim_state */ +#include <linux/swap.h> /* mm_account_reclaimed_pages() */ #include <linux/cache.h> #include <linux/init.h> #include <linux/export.h> @@ -211,9 +211,7 @@ static void slob_free_pages(void *b, int order) { struct page *sp = virt_to_page(b); - if (current->reclaim_state) - current->reclaim_state->reclaimed_slab += 1 << order; - + mm_account_reclaimed_pages(1 << order); mod_node_page_state(page_pgdat(sp), NR_SLAB_UNRECLAIMABLE_B, -(PAGE_SIZE << order)); __free_pages(sp, order); diff --git a/mm/slub.c b/mm/slub.c index 39327e98fce3..7aa30eef8235 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -11,7 +11,7 @@ */ #include <linux/mm.h> -#include <linux/swap.h> /* struct reclaim_state */ +#include <linux/swap.h> /* mm_account_reclaimed_pages() */ #include <linux/module.h> #include <linux/bit_spinlock.h> #include <linux/interrupt.h> @@ -2063,8 +2063,7 @@ static void __free_slab(struct kmem_cache *s, struct slab *slab) /* Make the mapping reset visible before clearing the flag */ smp_wmb(); __folio_clear_slab(folio); - if (current->reclaim_state) - current->reclaim_state->reclaimed_slab += pages; + mm_account_reclaimed_pages(pages); unaccount_slab(slab, order, s); __free_pages(&folio->page, order); }
During reclaim, we keep track of pages reclaimed from other means than LRU-based reclaim through scan_control->reclaim_state->reclaimed_slab, which we stash a pointer to in current task_struct. However, we keep track of more than just reclaimed slab pages through this. We also use it for clean file pages dropped through pruned inodes, and xfs buffer pages freed. Rename reclaimed_slab to reclaimed, and add a helper function that wraps updating it through current, so that future changes to this logic are contained within include/linux/swap.h. Signed-off-by: Yosry Ahmed <yosryahmed@google.com> --- fs/inode.c | 3 +-- fs/xfs/xfs_buf.c | 3 +-- include/linux/swap.h | 17 ++++++++++++++++- mm/slab.c | 3 +-- mm/slob.c | 6 ++---- mm/slub.c | 5 ++--- 6 files changed, 23 insertions(+), 14 deletions(-)