On Tue, Oct 10, 2017 at 02:08:55PM +0800, Huang, Ying wrote: > From: Huang Ying <ying.huang@xxxxxxxxx> > > When the VMA based swap readahead was introduced, a new knob > > /sys/kernel/mm/swap/vma_ra_max_order > > was added as the max window of VMA swap readahead. This is to make it > possible to use different max window for VMA based readahead and > original physical readahead. But Minchan Kim pointed out that this > will cause a regression because setting page-cluster sysctl to zero > cannot disable swap readahead with the change. > > To fix the regression, the page-cluster sysctl is used as the max > window of both the VMA based swap readahead and original physical swap > readahead. If more fine grained control is needed in the future, more > knobs can be added as the subordinate knobs of the page-cluster > sysctl. > > The vma_ra_max_order knob is deleted. Because the knob was > introduced in v4.14-rc1, and this patch is targeting being merged > before v4.14 releasing, there should be no existing users of this > newly added ABI. > > Cc: Johannes Weiner <hannes@xxxxxxxxxxx> > Cc: Rik van Riel <riel@xxxxxxxxxx> > Cc: Shaohua Li <shli@xxxxxxxxxx> > Cc: Hugh Dickins <hughd@xxxxxxxxxx> > Cc: Fengguang Wu <fengguang.wu@xxxxxxxxx> > Cc: Tim Chen <tim.c.chen@xxxxxxxxx> > Cc: Dave Hansen <dave.hansen@xxxxxxxxx> > Reported-by: Minchan Kim <minchan@xxxxxxxxxx> It seems your script is Ccing only with Cc: tag, not other tags. Fix it so any participant of topic can get the mail. > Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx> > --- > Documentation/ABI/testing/sysfs-kernel-mm-swap | 10 --------- > mm/swap_state.c | 31 ++------------------------ > 2 files changed, 2 insertions(+), 39 deletions(-) > > diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-swap b/Documentation/ABI/testing/sysfs-kernel-mm-swap > index 587db52084c7..94672016c268 100644 > --- a/Documentation/ABI/testing/sysfs-kernel-mm-swap > +++ b/Documentation/ABI/testing/sysfs-kernel-mm-swap > @@ -14,13 +14,3 @@ Description: Enable/disable VMA based swap readahead. > still used for tmpfs etc. other users. If set to > false, the global swap readahead algorithm will be > used for all swappable pages. > - > -What: /sys/kernel/mm/swap/vma_ra_max_order > -Date: August 2017 > -Contact: Linux memory management mailing list <linux-mm@xxxxxxxxx> > -Description: The max readahead size in order for VMA based swap readahead > - > - VMA based swap readahead algorithm will readahead at > - most 1 << max_order pages for each readahead. The > - real readahead size for each readahead will be scaled > - according to the estimation algorithm. > diff --git a/mm/swap_state.c b/mm/swap_state.c > index ed91091d1e68..4d01ecff62d9 100644 > --- a/mm/swap_state.c > +++ b/mm/swap_state.c > @@ -39,10 +39,6 @@ struct address_space *swapper_spaces[MAX_SWAPFILES]; > static unsigned int nr_swapper_spaces[MAX_SWAPFILES]; > bool swap_vma_readahead = true; > > -#define SWAP_RA_MAX_ORDER_DEFAULT 3 > - > -static int swap_ra_max_order = SWAP_RA_MAX_ORDER_DEFAULT; > - > #define SWAP_RA_WIN_SHIFT (PAGE_SHIFT / 2) > #define SWAP_RA_HITS_MASK ((1UL << SWAP_RA_WIN_SHIFT) - 1) > #define SWAP_RA_HITS_MAX SWAP_RA_HITS_MASK > @@ -672,7 +668,8 @@ struct page *swap_readahead_detect(struct vm_fault *vmf, > if (page) > return page; > > - max_win = 1 << READ_ONCE(swap_ra_max_order); > + max_win = 1 << min_t(unsigned int, READ_ONCE(page_cluster), > + SWAP_RA_ORDER_CEILING); Why doesn't you check it in swap_use_vma_readahead in my original patch? My purpose in there is to avoid unnecessary function call and lookup_swap_cache in there. If you really want to do that in swap_readahead_detect itself, please move above routine to ahead of faddr = vmf->address to avoid unncessary instructions. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
