| Message ID | 20230222195247.791227-1-peterx@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] mm/khugepaged: alloc_charge_hpage() take care of mem charge errors | expand |
On Wed, Feb 22, 2023 at 11:52 AM Peter Xu <peterx@redhat.com> wrote: > > If memory charge failed, instead of returning the hpage but with an error, > allow the function to cleanup the folio properly, which is normally what a > function should do in this case - either return successfully, or return > with no side effect of partial runs with an indicated error. > > This will also avoid the caller calling mem_cgroup_uncharge() unnecessarily > with either anon or shmem path (even if it's safe to do so). Thanks for the cleanup. Reviewed-by: Yang Shi <shy828301@gmail.com> > > Cc: Yang Shi <shy828301@gmail.com> > Reviewed-by: David Stevens <stevensd@chromium.org> > Acked-by: Johannes Weiner <hannes@cmpxchg.org> > Signed-off-by: Peter Xu <peterx@redhat.com> > --- > v1->v2: > - Enhance commit message, drop "Fixes:" and "Cc: stable" tag, add R-bs. > --- > mm/khugepaged.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index 8dbc39896811..941d1c7ea910 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -1063,12 +1063,19 @@ static int alloc_charge_hpage(struct page **hpage, struct mm_struct *mm, > gfp_t gfp = (cc->is_khugepaged ? alloc_hugepage_khugepaged_gfpmask() : > GFP_TRANSHUGE); > int node = hpage_collapse_find_target_node(cc); > + struct folio *folio; > > if (!hpage_collapse_alloc_page(hpage, gfp, node, &cc->alloc_nmask)) > return SCAN_ALLOC_HUGE_PAGE_FAIL; > - if (unlikely(mem_cgroup_charge(page_folio(*hpage), mm, gfp))) > + > + folio = page_folio(*hpage); > + if (unlikely(mem_cgroup_charge(folio, mm, gfp))) { > + folio_put(folio); > + *hpage = NULL; > return SCAN_CGROUP_CHARGE_FAIL; > + } > count_memcg_page_event(*hpage, THP_COLLAPSE_ALLOC); > + > return SCAN_SUCCEED; > } > > -- > 2.39.1 >
On Feb 22 14:53, Yang Shi wrote: > On Wed, Feb 22, 2023 at 11:52 AM Peter Xu <peterx@redhat.com> wrote: > > > > If memory charge failed, instead of returning the hpage but with an error, > > allow the function to cleanup the folio properly, which is normally what a > > function should do in this case - either return successfully, or return > > with no side effect of partial runs with an indicated error. > > > > This will also avoid the caller calling mem_cgroup_uncharge() unnecessarily > > with either anon or shmem path (even if it's safe to do so). > > Thanks for the cleanup. Reviewed-by: Yang Shi <shy828301@gmail.com> > > > > > Cc: Yang Shi <shy828301@gmail.com> > > Reviewed-by: David Stevens <stevensd@chromium.org> > > Acked-by: Johannes Weiner <hannes@cmpxchg.org> > > Signed-off-by: Peter Xu <peterx@redhat.com> > > --- > > v1->v2: > > - Enhance commit message, drop "Fixes:" and "Cc: stable" tag, add R-bs. > > --- > > mm/khugepaged.c | 9 ++++++++- > > 1 file changed, 8 insertions(+), 1 deletion(-) > > > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > > index 8dbc39896811..941d1c7ea910 100644 > > --- a/mm/khugepaged.c > > +++ b/mm/khugepaged.c > > @@ -1063,12 +1063,19 @@ static int alloc_charge_hpage(struct page **hpage, struct mm_struct *mm, > > gfp_t gfp = (cc->is_khugepaged ? alloc_hugepage_khugepaged_gfpmask() : > > GFP_TRANSHUGE); > > int node = hpage_collapse_find_target_node(cc); > > + struct folio *folio; > > > > if (!hpage_collapse_alloc_page(hpage, gfp, node, &cc->alloc_nmask)) > > return SCAN_ALLOC_HUGE_PAGE_FAIL; > > - if (unlikely(mem_cgroup_charge(page_folio(*hpage), mm, gfp))) > > + > > + folio = page_folio(*hpage); > > + if (unlikely(mem_cgroup_charge(folio, mm, gfp))) { > > + folio_put(folio); > > + *hpage = NULL; > > return SCAN_CGROUP_CHARGE_FAIL; > > + } > > count_memcg_page_event(*hpage, THP_COLLAPSE_ALLOC); > > + > > return SCAN_SUCCEED; > > } > > > > -- > > 2.39.1 > > > Thanks, Peter. Can we also get rid of the unnecessary mem_cgroup_uncharge() calls while we're at it? Maybe this deserves a separate patch, but after Yang's cleanup of the !NUMA case (where we would preallocate a hugepage) we can depend on put_page() do take care of that for us. Regardless, can have my Reviewed-by: Zach O'Keefe <zokeefe@google.com>
On Thu, Mar 02, 2023 at 03:21:50PM -0800, Zach O'Keefe wrote: > On Feb 22 14:53, Yang Shi wrote: > > On Wed, Feb 22, 2023 at 11:52 AM Peter Xu <peterx@redhat.com> wrote: > > > > > > If memory charge failed, instead of returning the hpage but with an error, > > > allow the function to cleanup the folio properly, which is normally what a > > > function should do in this case - either return successfully, or return > > > with no side effect of partial runs with an indicated error. > > > > > > This will also avoid the caller calling mem_cgroup_uncharge() unnecessarily > > > with either anon or shmem path (even if it's safe to do so). > > > > Thanks for the cleanup. Reviewed-by: Yang Shi <shy828301@gmail.com> > > > > > > > > Cc: Yang Shi <shy828301@gmail.com> > > > Reviewed-by: David Stevens <stevensd@chromium.org> > > > Acked-by: Johannes Weiner <hannes@cmpxchg.org> > > > Signed-off-by: Peter Xu <peterx@redhat.com> > > > --- > > > v1->v2: > > > - Enhance commit message, drop "Fixes:" and "Cc: stable" tag, add R-bs. > > > --- > > > mm/khugepaged.c | 9 ++++++++- > > > 1 file changed, 8 insertions(+), 1 deletion(-) > > > > > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > > > index 8dbc39896811..941d1c7ea910 100644 > > > --- a/mm/khugepaged.c > > > +++ b/mm/khugepaged.c > > > @@ -1063,12 +1063,19 @@ static int alloc_charge_hpage(struct page **hpage, struct mm_struct *mm, > > > gfp_t gfp = (cc->is_khugepaged ? alloc_hugepage_khugepaged_gfpmask() : > > > GFP_TRANSHUGE); > > > int node = hpage_collapse_find_target_node(cc); > > > + struct folio *folio; > > > > > > if (!hpage_collapse_alloc_page(hpage, gfp, node, &cc->alloc_nmask)) > > > return SCAN_ALLOC_HUGE_PAGE_FAIL; > > > - if (unlikely(mem_cgroup_charge(page_folio(*hpage), mm, gfp))) > > > + > > > + folio = page_folio(*hpage); > > > + if (unlikely(mem_cgroup_charge(folio, mm, gfp))) { > > > + folio_put(folio); > > > + *hpage = NULL; > > > return SCAN_CGROUP_CHARGE_FAIL; > > > + } > > > count_memcg_page_event(*hpage, THP_COLLAPSE_ALLOC); > > > + > > > return SCAN_SUCCEED; > > > } > > > > > > -- > > > 2.39.1 > > > > > > > Thanks, Peter. > > Can we also get rid of the unnecessary mem_cgroup_uncharge() calls while we're > at it? Maybe this deserves a separate patch, but after Yang's cleanup of the > !NUMA case (where we would preallocate a hugepage) we can depend on put_page() > do take care of that for us. Makes sense to me. I can prepare a separate patch to clean it up. > > Regardless, can have my > > Reviewed-by: Zach O'Keefe <zokeefe@google.com> Thanks!
diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 8dbc39896811..941d1c7ea910 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1063,12 +1063,19 @@ static int alloc_charge_hpage(struct page **hpage, struct mm_struct *mm, gfp_t gfp = (cc->is_khugepaged ? alloc_hugepage_khugepaged_gfpmask() : GFP_TRANSHUGE); int node = hpage_collapse_find_target_node(cc); + struct folio *folio; if (!hpage_collapse_alloc_page(hpage, gfp, node, &cc->alloc_nmask)) return SCAN_ALLOC_HUGE_PAGE_FAIL; - if (unlikely(mem_cgroup_charge(page_folio(*hpage), mm, gfp))) + + folio = page_folio(*hpage); + if (unlikely(mem_cgroup_charge(folio, mm, gfp))) { + folio_put(folio); + *hpage = NULL; return SCAN_CGROUP_CHARGE_FAIL; + } count_memcg_page_event(*hpage, THP_COLLAPSE_ALLOC); + return SCAN_SUCCEED; }