From: Michal Hocko <mhocko@suse.com> To: David Hildenbrand <david@redhat.com> Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>, Arnd Bergmann <arnd@arndb.de>, Oscar Salvador <osalvador@suse.de>, Matthew Wilcox <willy@infradead.org>, Andrea Arcangeli <aarcange@redhat.com>, Minchan Kim <minchan@kernel.org>, Jann Horn <jannh@google.com>, Jason Gunthorpe <jgg@ziepe.ca>, Dave Hansen <dave.hansen@intel.com>, Hugh Dickins <hughd@google.com>, Rik van Riel <riel@surriel.com>, "Michael S . Tsirkin" <mst@redhat.com>, "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>, Vlastimil Babka <vbabka@suse.cz>, Richard Henderson <rth@twiddle.net>, Ivan Kokshaysky <ink@jurassic.park.msu.ru>, Matt Turner <mattst88@gmail.com>, Thomas Bogendoerfer <tsbogend@alpha.franken.de>, "James E.J. Bottomley" <James.Bottomley@hansenpartnership.com>, Helge Deller <deller@gmx.de>, Chris Zankel <chris@zankel.net>, Max Filippov <jcmvbkbc@gmail.com>, linux-alpha@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-xtensa@linux-xtensa.org, linux-arch@vger.kernel.org Subject: Re: [PATCH RFC] mm/madvise: introduce MADV_POPULATE to prefault/prealloc memory Date: Fri, 19 Feb 2021 11:35:21 +0100 [thread overview] Message-ID: <YC+UaTVUn0o4Zynz@dhcp22.suse.cz> (raw) In-Reply-To: <20210217154844.12392-1-david@redhat.com> On Wed 17-02-21 16:48:44, David Hildenbrand wrote: [...] I only got to the implementation now. > +static long madvise_populate(struct vm_area_struct *vma, > + struct vm_area_struct **prev, > + unsigned long start, unsigned long end) > +{ > + struct mm_struct *mm = vma->vm_mm; > + unsigned long tmp_end; > + int locked = 1; > + long pages; > + > + *prev = vma; > + > + while (start < end) { > + /* > + * We might have temporarily dropped the lock. For example, > + * our VMA might have been split. > + */ > + if (!vma || start >= vma->vm_end) { > + vma = find_vma(mm, start); > + if (!vma) > + return -ENOMEM; > + } Why do you need to find a vma when you already have one. do_madvise will give you your vma already. I do understand that you want to finish the vma for some errors but that shouldn't require handling vmas. You should be in the shope of one here unless I miss anything. > + > + /* Bail out on incompatible VMA types. */ > + if (vma->vm_flags & (VM_IO | VM_PFNMAP) || > + !vma_is_accessible(vma)) { > + return -EINVAL; > + } > + > + /* > + * Populate pages and take care of VM_LOCKED: simulate user > + * space access. > + * > + * For private, writable mappings, trigger a write fault to > + * break COW (i.e., shared zeropage). For other mappings (i.e., > + * read-only, shared), trigger a read fault. > + */ > + tmp_end = min_t(unsigned long, end, vma->vm_end); > + pages = populate_vma_page_range(vma, start, tmp_end, &locked); > + if (!locked) { > + mmap_read_lock(mm); > + *prev = NULL; > + vma = NULL; > + } > + if (pages < 0) { > + switch (pages) { > + case -EINTR: > + case -ENOMEM: > + return pages; > + case -EHWPOISON: > + /* Skip over any poisoned pages. */ > + start += PAGE_SIZE; > + continue; > + case -EBUSY: > + case -EAGAIN: > + continue; > + default: > + pr_warn_once("%s: unhandled return value: %ld\n", > + __func__, pages); > + return -ENOMEM; > + } > + } > + start += pages * PAGE_SIZE; > + } > + return 0; > +} > + > /* > * Application wants to free up the pages and associated backing store. > * This is effectively punching a hole into the middle of a file. > @@ -934,6 +1001,8 @@ madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev, > case MADV_FREE: > case MADV_DONTNEED: > return madvise_dontneed_free(vma, prev, start, end, behavior); > + case MADV_POPULATE: > + return madvise_populate(vma, prev, start, end); > default: > return madvise_behavior(vma, prev, start, end, behavior); > } > @@ -954,6 +1023,7 @@ madvise_behavior_valid(int behavior) > case MADV_FREE: > case MADV_COLD: > case MADV_PAGEOUT: > + case MADV_POPULATE: > #ifdef CONFIG_KSM > case MADV_MERGEABLE: > case MADV_UNMERGEABLE: > -- > 2.29.2 > -- Michal Hocko SUSE Labs
WARNING: multiple messages have this Message-ID (diff)
From: Michal Hocko <mhocko@suse.com> To: David Hildenbrand <david@redhat.com> Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>, Arnd Bergmann <arnd@arndb.de>, Oscar Salvador <osalvador@suse.de>, Matthew Wilcox <willy@infradead.org>, Andrea Arcangeli <aarcange@redhat.com>, Minchan Kim <minchan@kernel.org>, Jann Horn <jannh@google.com>, Jason Gunthorpe <jgg@ziepe.ca>, Dave Hansen <dave.hansen@intel.com>, Hugh Dickins <hughd@google.com>, Rik van Riel <riel@surriel.com>, "Michael S . Tsirkin" <mst@redhat.com>, "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>, Vlastimil Babka <vbabka@suse.cz>, Richard Henderson <rth@twiddle.net>, Ivan Kokshaysky <ink@jurassic.park.msu.ru>, Matt Turner <mattst88@gmail.com>, Thomas Bogendoerfer <tsbogend@alpha.franken.de>, James E.J. Bottomle Subject: Re: [PATCH RFC] mm/madvise: introduce MADV_POPULATE to prefault/prealloc memory Date: Fri, 19 Feb 2021 11:35:21 +0100 [thread overview] Message-ID: <YC+UaTVUn0o4Zynz@dhcp22.suse.cz> (raw) In-Reply-To: <20210217154844.12392-1-david@redhat.com> On Wed 17-02-21 16:48:44, David Hildenbrand wrote: [...] I only got to the implementation now. > +static long madvise_populate(struct vm_area_struct *vma, > + struct vm_area_struct **prev, > + unsigned long start, unsigned long end) > +{ > + struct mm_struct *mm = vma->vm_mm; > + unsigned long tmp_end; > + int locked = 1; > + long pages; > + > + *prev = vma; > + > + while (start < end) { > + /* > + * We might have temporarily dropped the lock. For example, > + * our VMA might have been split. > + */ > + if (!vma || start >= vma->vm_end) { > + vma = find_vma(mm, start); > + if (!vma) > + return -ENOMEM; > + } Why do you need to find a vma when you already have one. do_madvise will give you your vma already. I do understand that you want to finish the vma for some errors but that shouldn't require handling vmas. You should be in the shope of one here unless I miss anything. > + > + /* Bail out on incompatible VMA types. */ > + if (vma->vm_flags & (VM_IO | VM_PFNMAP) || > + !vma_is_accessible(vma)) { > + return -EINVAL; > + } > + > + /* > + * Populate pages and take care of VM_LOCKED: simulate user > + * space access. > + * > + * For private, writable mappings, trigger a write fault to > + * break COW (i.e., shared zeropage). For other mappings (i.e., > + * read-only, shared), trigger a read fault. > + */ > + tmp_end = min_t(unsigned long, end, vma->vm_end); > + pages = populate_vma_page_range(vma, start, tmp_end, &locked); > + if (!locked) { > + mmap_read_lock(mm); > + *prev = NULL; > + vma = NULL; > + } > + if (pages < 0) { > + switch (pages) { > + case -EINTR: > + case -ENOMEM: > + return pages; > + case -EHWPOISON: > + /* Skip over any poisoned pages. */ > + start += PAGE_SIZE; > + continue; > + case -EBUSY: > + case -EAGAIN: > + continue; > + default: > + pr_warn_once("%s: unhandled return value: %ld\n", > + __func__, pages); > + return -ENOMEM; > + } > + } > + start += pages * PAGE_SIZE; > + } > + return 0; > +} > + > /* > * Application wants to free up the pages and associated backing store. > * This is effectively punching a hole into the middle of a file. > @@ -934,6 +1001,8 @@ madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev, > case MADV_FREE: > case MADV_DONTNEED: > return madvise_dontneed_free(vma, prev, start, end, behavior); > + case MADV_POPULATE: > + return madvise_populate(vma, prev, start, end); > default: > return madvise_behavior(vma, prev, start, end, behavior); > } > @@ -954,6 +1023,7 @@ madvise_behavior_valid(int behavior) > case MADV_FREE: > case MADV_COLD: > case MADV_PAGEOUT: > + case MADV_POPULATE: > #ifdef CONFIG_KSM > case MADV_MERGEABLE: > case MADV_UNMERGEABLE: > -- > 2.29.2 > -- Michal Hocko SUSE Labs
next prev parent reply other threads:[~2021-02-19 10:36 UTC|newest] Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-02-17 15:48 [PATCH RFC] mm/madvise: introduce MADV_POPULATE to prefault/prealloc memory David Hildenbrand 2021-02-17 15:48 ` David Hildenbrand 2021-02-17 16:46 ` Dave Hansen 2021-02-17 16:46 ` Dave Hansen 2021-02-17 17:06 ` David Hildenbrand 2021-02-17 17:06 ` David Hildenbrand 2021-02-17 17:21 ` Vlastimil Babka 2021-02-17 17:21 ` Vlastimil Babka 2021-02-18 11:07 ` Rolf Eike Beer 2021-02-18 11:07 ` Rolf Eike Beer 2021-02-18 11:27 ` David Hildenbrand 2021-02-18 11:27 ` David Hildenbrand 2021-02-18 10:25 ` Michal Hocko 2021-02-18 10:25 ` Michal Hocko 2021-02-18 10:44 ` David Hildenbrand 2021-02-18 10:44 ` David Hildenbrand 2021-02-18 10:54 ` David Hildenbrand 2021-02-18 10:54 ` David Hildenbrand 2021-02-18 11:28 ` Michal Hocko 2021-02-18 11:28 ` Michal Hocko 2021-02-18 11:27 ` Michal Hocko 2021-02-18 11:27 ` Michal Hocko 2021-02-18 11:38 ` David Hildenbrand 2021-02-18 11:38 ` David Hildenbrand 2021-02-18 12:22 ` [PATCH RFC] madvise.2: Document MADV_POPULATE David Hildenbrand 2021-02-18 12:22 ` David Hildenbrand 2021-02-18 22:59 ` [PATCH RFC] mm/madvise: introduce MADV_POPULATE to prefault/prealloc memory Peter Xu 2021-02-18 22:59 ` Peter Xu 2021-02-19 8:20 ` David Hildenbrand 2021-02-19 8:20 ` David Hildenbrand 2021-02-19 16:31 ` Peter Xu 2021-02-19 16:31 ` Peter Xu 2021-02-19 17:13 ` David Hildenbrand 2021-02-19 17:13 ` David Hildenbrand 2021-02-19 19:14 ` David Hildenbrand 2021-02-19 19:14 ` David Hildenbrand 2021-02-19 19:25 ` Mike Kravetz 2021-02-19 19:25 ` Mike Kravetz 2021-02-20 9:01 ` David Hildenbrand 2021-02-20 9:01 ` David Hildenbrand 2021-02-19 19:23 ` Peter Xu 2021-02-19 19:23 ` Peter Xu 2021-02-19 20:04 ` David Hildenbrand 2021-02-19 20:04 ` David Hildenbrand 2021-02-22 12:46 ` Michal Hocko 2021-02-22 12:46 ` Michal Hocko 2021-02-22 12:52 ` David Hildenbrand 2021-02-22 12:52 ` David Hildenbrand 2021-02-19 10:35 ` Michal Hocko [this message] 2021-02-19 10:35 ` Michal Hocko 2021-02-19 10:43 ` David Hildenbrand 2021-02-19 10:43 ` David Hildenbrand 2021-02-19 11:04 ` Michal Hocko 2021-02-19 11:04 ` Michal Hocko 2021-02-19 11:10 ` David Hildenbrand 2021-02-19 11:10 ` David Hildenbrand 2021-02-20 9:12 ` David Hildenbrand 2021-02-20 9:12 ` David Hildenbrand 2021-02-22 12:56 ` Michal Hocko 2021-02-22 12:56 ` Michal Hocko 2021-02-22 12:59 ` David Hildenbrand 2021-02-22 12:59 ` David Hildenbrand 2021-02-22 13:19 ` Michal Hocko 2021-02-22 13:19 ` Michal Hocko 2021-02-22 13:22 ` David Hildenbrand 2021-02-22 13:22 ` David Hildenbrand 2021-02-22 14:02 ` Michal Hocko 2021-02-22 14:02 ` Michal Hocko 2021-02-22 15:30 ` David Hildenbrand 2021-02-22 15:30 ` David Hildenbrand 2021-02-24 14:25 ` David Hildenbrand 2021-02-24 14:25 ` David Hildenbrand 2021-02-24 14:38 ` David Hildenbrand 2021-02-24 14:38 ` David Hildenbrand 2021-02-25 8:41 ` David Hildenbrand 2021-02-25 8:41 ` David Hildenbrand
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