From: Hugh Dickins <hughd@google.com> To: Dmitry Fink <dmitry.fink@palm.com> Cc: Andrew Morton <akpm@linux-foundation.org>, Minchan Kim <minchan.kim@gmail.com>, "linux-mm@kvack.org" <linux-mm@kvack.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org> Subject: Re: [PATCH] mmap: Fix and tidy up overcommit page arithmetic Date: Mon, 11 Jul 2011 10:33:11 -0700 (PDT) [thread overview] Message-ID: <alpine.LSU.2.00.1107111030480.1752@sister.anvils> (raw) In-Reply-To: <1310348510-16957-1-git-send-email-dmitry.fink@palm.com> On Sun, 10 Jul 2011, Dmitry Fink wrote: > - shmem pages are not immediately available, but they are not > potentially available either, even if we swap them out, they will > just relocate from memory into swap, total amount of immediate and > potentially available memory is not going to be affected, so we > shouldn't count them as potentially free in the first place. > > - nr_free_pages() is not an expensive operation anymore, there is > no need to split the decision making in two halves and repeat code. > > Signed-off-by: Dmitry Fink <dmitry.fink@palm.com> > Reviewed-by: Minchan Kim <minchan.kim@gmail.com> > Acked-by: Hugh Dickins <hughd@google.com> Just right: thanks a lot for redoing it this way, Dmitry. > --- > mm/mmap.c | 34 +++++++++++++--------------------- > mm/nommu.c | 34 +++++++++++++--------------------- > 2 files changed, 26 insertions(+), 42 deletions(-) > > diff --git a/mm/mmap.c b/mm/mmap.c > index d49736f..a65efd4 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -122,9 +122,17 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) > return 0; > > if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { > - unsigned long n; > + free = global_page_state(NR_FREE_PAGES); > + free += global_page_state(NR_FILE_PAGES); > + > + /* > + * shmem pages shouldn't be counted as free in this > + * case, they can't be purged, only swapped out, and > + * that won't affect the overall amount of available > + * memory in the system. > + */ > + free -= global_page_state(NR_SHMEM); > > - free = global_page_state(NR_FILE_PAGES); > free += nr_swap_pages; > > /* > @@ -136,34 +144,18 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) > free += global_page_state(NR_SLAB_RECLAIMABLE); > > /* > - * Leave the last 3% for root > - */ > - if (!cap_sys_admin) > - free -= free / 32; > - > - if (free > pages) > - return 0; > - > - /* > - * nr_free_pages() is very expensive on large systems, > - * only call if we're about to fail. > - */ > - n = nr_free_pages(); > - > - /* > * Leave reserved pages. The pages are not for anonymous pages. > */ > - if (n <= totalreserve_pages) > + if (free <= totalreserve_pages) > goto error; > else > - n -= totalreserve_pages; > + free -= totalreserve_pages; > > /* > * Leave the last 3% for root > */ > if (!cap_sys_admin) > - n -= n / 32; > - free += n; > + free -= free / 32; > > if (free > pages) > return 0; > diff --git a/mm/nommu.c b/mm/nommu.c > index 9edc897..76f2b4b 100644 > --- a/mm/nommu.c > +++ b/mm/nommu.c > @@ -1885,9 +1885,17 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) > return 0; > > if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { > - unsigned long n; > + free = global_page_state(NR_FREE_PAGES); > + free += global_page_state(NR_FILE_PAGES); > + > + /* > + * shmem pages shouldn't be counted as free in this > + * case, they can't be purged, only swapped out, and > + * that won't affect the overall amount of available > + * memory in the system. > + */ > + free -= global_page_state(NR_SHMEM); > > - free = global_page_state(NR_FILE_PAGES); > free += nr_swap_pages; > > /* > @@ -1899,34 +1907,18 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) > free += global_page_state(NR_SLAB_RECLAIMABLE); > > /* > - * Leave the last 3% for root > - */ > - if (!cap_sys_admin) > - free -= free / 32; > - > - if (free > pages) > - return 0; > - > - /* > - * nr_free_pages() is very expensive on large systems, > - * only call if we're about to fail. > - */ > - n = nr_free_pages(); > - > - /* > * Leave reserved pages. The pages are not for anonymous pages. > */ > - if (n <= totalreserve_pages) > + if (free <= totalreserve_pages) > goto error; > else > - n -= totalreserve_pages; > + free -= totalreserve_pages; > > /* > * Leave the last 3% for root > */ > if (!cap_sys_admin) > - n -= n / 32; > - free += n; > + free -= free / 32; > > if (free > pages) > return 0; > -- > 1.7.6
WARNING: multiple messages have this Message-ID (diff)
From: Hugh Dickins <hughd@google.com> To: Dmitry Fink <dmitry.fink@palm.com> Cc: Andrew Morton <akpm@linux-foundation.org>, Minchan Kim <minchan.kim@gmail.com>, "linux-mm@kvack.org" <linux-mm@kvack.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org> Subject: Re: [PATCH] mmap: Fix and tidy up overcommit page arithmetic Date: Mon, 11 Jul 2011 10:33:11 -0700 (PDT) [thread overview] Message-ID: <alpine.LSU.2.00.1107111030480.1752@sister.anvils> (raw) In-Reply-To: <1310348510-16957-1-git-send-email-dmitry.fink@palm.com> On Sun, 10 Jul 2011, Dmitry Fink wrote: > - shmem pages are not immediately available, but they are not > potentially available either, even if we swap them out, they will > just relocate from memory into swap, total amount of immediate and > potentially available memory is not going to be affected, so we > shouldn't count them as potentially free in the first place. > > - nr_free_pages() is not an expensive operation anymore, there is > no need to split the decision making in two halves and repeat code. > > Signed-off-by: Dmitry Fink <dmitry.fink@palm.com> > Reviewed-by: Minchan Kim <minchan.kim@gmail.com> > Acked-by: Hugh Dickins <hughd@google.com> Just right: thanks a lot for redoing it this way, Dmitry. > --- > mm/mmap.c | 34 +++++++++++++--------------------- > mm/nommu.c | 34 +++++++++++++--------------------- > 2 files changed, 26 insertions(+), 42 deletions(-) > > diff --git a/mm/mmap.c b/mm/mmap.c > index d49736f..a65efd4 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -122,9 +122,17 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) > return 0; > > if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { > - unsigned long n; > + free = global_page_state(NR_FREE_PAGES); > + free += global_page_state(NR_FILE_PAGES); > + > + /* > + * shmem pages shouldn't be counted as free in this > + * case, they can't be purged, only swapped out, and > + * that won't affect the overall amount of available > + * memory in the system. > + */ > + free -= global_page_state(NR_SHMEM); > > - free = global_page_state(NR_FILE_PAGES); > free += nr_swap_pages; > > /* > @@ -136,34 +144,18 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) > free += global_page_state(NR_SLAB_RECLAIMABLE); > > /* > - * Leave the last 3% for root > - */ > - if (!cap_sys_admin) > - free -= free / 32; > - > - if (free > pages) > - return 0; > - > - /* > - * nr_free_pages() is very expensive on large systems, > - * only call if we're about to fail. > - */ > - n = nr_free_pages(); > - > - /* > * Leave reserved pages. The pages are not for anonymous pages. > */ > - if (n <= totalreserve_pages) > + if (free <= totalreserve_pages) > goto error; > else > - n -= totalreserve_pages; > + free -= totalreserve_pages; > > /* > * Leave the last 3% for root > */ > if (!cap_sys_admin) > - n -= n / 32; > - free += n; > + free -= free / 32; > > if (free > pages) > return 0; > diff --git a/mm/nommu.c b/mm/nommu.c > index 9edc897..76f2b4b 100644 > --- a/mm/nommu.c > +++ b/mm/nommu.c > @@ -1885,9 +1885,17 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) > return 0; > > if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { > - unsigned long n; > + free = global_page_state(NR_FREE_PAGES); > + free += global_page_state(NR_FILE_PAGES); > + > + /* > + * shmem pages shouldn't be counted as free in this > + * case, they can't be purged, only swapped out, and > + * that won't affect the overall amount of available > + * memory in the system. > + */ > + free -= global_page_state(NR_SHMEM); > > - free = global_page_state(NR_FILE_PAGES); > free += nr_swap_pages; > > /* > @@ -1899,34 +1907,18 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) > free += global_page_state(NR_SLAB_RECLAIMABLE); > > /* > - * Leave the last 3% for root > - */ > - if (!cap_sys_admin) > - free -= free / 32; > - > - if (free > pages) > - return 0; > - > - /* > - * nr_free_pages() is very expensive on large systems, > - * only call if we're about to fail. > - */ > - n = nr_free_pages(); > - > - /* > * Leave reserved pages. The pages are not for anonymous pages. > */ > - if (n <= totalreserve_pages) > + if (free <= totalreserve_pages) > goto error; > else > - n -= totalreserve_pages; > + free -= totalreserve_pages; > > /* > * Leave the last 3% for root > */ > if (!cap_sys_admin) > - n -= n / 32; > - free += n; > + free -= free / 32; > > if (free > pages) > return 0; > -- > 1.7.6 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2011-07-11 17:33 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2011-07-03 19:39 [PATCH 1/1] mmap: Don't count shmem pages as free in __vm_enough_memory Dmitry Fink 2011-07-03 19:39 ` Dmitry Fink 2011-07-04 0:43 ` Minchan Kim 2011-07-04 0:43 ` Minchan Kim 2011-07-04 3:10 ` Dmitry Fink (Palm GBU) 2011-07-04 3:10 ` Dmitry Fink (Palm GBU) 2011-07-04 3:48 ` Minchan Kim 2011-07-04 3:48 ` Minchan Kim 2011-07-08 22:22 ` Hugh Dickins 2011-07-08 22:22 ` Hugh Dickins 2011-07-09 20:42 ` [PATCH] mmap: Fix and tidy up overcommit page arithmetic Dmitry Fink 2011-07-09 20:42 ` Dmitry Fink 2011-07-09 20:55 ` Dmitry Fink 2011-07-09 20:55 ` Dmitry Fink 2011-07-10 23:08 ` Minchan Kim 2011-07-10 23:08 ` Minchan Kim 2011-07-11 1:41 ` Dmitry Fink 2011-07-11 1:41 ` Dmitry Fink 2011-07-11 17:33 ` Hugh Dickins [this message] 2011-07-11 17:33 ` Hugh Dickins
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