diff for duplicates of <87pog3b6x8.fsf@yhuang-dev.intel.com> diff --git a/a/1.txt b/N1/1.txt index 2d21440..216f9c1 100644 --- a/a/1.txt +++ b/N1/1.txt @@ -18,13 +18,13 @@ Tim Chen <tim.c.chen@linux.intel.com> writes: >> > > > > > >> > > > > > From: Huang Ying <ying.huang@intel.com> >> > > > > > ->> > > > > > A void swapcache_free_entries(swp_entry_t *entries, int n) ->> > > > > > A { ->> > > > > > A struct swap_info_struct *p, *prev; +>> > > > > > void swapcache_free_entries(swp_entry_t *entries, int n) +>> > > > > > { +>> > > > > > struct swap_info_struct *p, *prev; >> > > > > > @@ -1075,6 +1083,10 @@ void swapcache_free_entries(swp_entry_t *entries, int n) ->> > > > > > A ->> > > > > > A prev = NULL; ->> > > > > > A p = NULL; +>> > > > > > +>> > > > > > prev = NULL; +>> > > > > > p = NULL; >> > > > > > + >> > > > > > + /* Sort swap entries by swap device, so each lock is only taken once. */ >> > > > > > + if (nr_swapfiles > 1) @@ -41,7 +41,7 @@ Tim Chen <tim.c.chen@linux.intel.com> writes: >> > > > > >> > > > > How about lazy sorting approach? IOW, if we found prev != p and, >> > > > > then we can sort it. ->> > > > Yes.A A That should be better.A A I just don't know whether the added +>> > > > Yes. That should be better. I just don't know whether the added >> > > > complexity is necessary, given the array is short and sort is fast. >> > > Huh? >> > > @@ -50,14 +50,14 @@ Tim Chen <tim.c.chen@linux.intel.com> writes: >> > > 3. swapoff /dev/XXX2 >> > > 4. use only one swap >> > > 5. then, always pointless sort. ->> > Yes.A A In this situation we will do unnecessary sorting.A A What I don't +>> > Yes. In this situation we will do unnecessary sorting. What I don't >> > know is whether the unnecessary sorting will hurt performance in real ->> > life.A A I can do some measurement. +>> > life. I can do some measurement. >> I tested the patch with 1 swap device and 1 process to eat memory ->> (remove the "if (nr_swapfiles > 1)" for test).A A +>> (remove the "if (nr_swapfiles > 1)" for test). > > It is possible that nr_swapfiles > 1 when we have only 1 swapfile due -> to swapoff. A The nr_swapfiles never decrement on swapoff. +> to swapoff. The nr_swapfiles never decrement on swapoff. > We will need to use another counter in alloc_swap_info and > swapoff to track the true number of swapfiles in use to have a fast path > that avoid the search and sort for the 1 swap case. @@ -71,9 +71,3 @@ Do you think so? Best Regards, Huang, Ying - --- -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/ . -Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> diff --git a/a/content_digest b/N1/content_digest index 032f4dc..cefac7b 100644 --- a/a/content_digest +++ b/N1/content_digest @@ -9,12 +9,12 @@ "Subject\0Re: [PATCH -mm -v3] mm, swap: Sort swap entries before free\0" "Date\0Sun, 23 Apr 2017 21:16:35 +0800\0" "To\0Tim Chen <tim.c.chen@linux.intel.com>\0" - "Cc\0Huang" + "Cc\0Huang\\" Ying <ying.huang@intel.com> Minchan Kim <minchan@kernel.org> Andrew Morton <akpm@linux-foundation.org> - linux-mm@kvack.org - linux-kernel@vger.kernel.org + <linux-mm@kvack.org> + <linux-kernel@vger.kernel.org> Hugh Dickins <hughd@google.com> Shaohua Li <shli@kernel.org> " Rik van Riel <riel@redhat.com>\0" @@ -40,13 +40,13 @@ ">> > > > > > \n" ">> > > > > > From: Huang Ying <ying.huang@intel.com>\n" ">> > > > > > \n" - ">> > > > > > A void swapcache_free_entries(swp_entry_t *entries, int n)\n" - ">> > > > > > A {\n" - ">> > > > > > A \tstruct swap_info_struct *p, *prev;\n" + ">> > > > > > \302\240void swapcache_free_entries(swp_entry_t *entries, int n)\n" + ">> > > > > > \302\240{\n" + ">> > > > > > \302\240\tstruct swap_info_struct *p, *prev;\n" ">> > > > > > @@ -1075,6 +1083,10 @@ void swapcache_free_entries(swp_entry_t *entries, int n)\n" - ">> > > > > > A \n" - ">> > > > > > A \tprev = NULL;\n" - ">> > > > > > A \tp = NULL;\n" + ">> > > > > > \302\240\n" + ">> > > > > > \302\240\tprev = NULL;\n" + ">> > > > > > \302\240\tp = NULL;\n" ">> > > > > > +\n" ">> > > > > > +\t/* Sort swap entries by swap device, so each lock is only taken once. */\n" ">> > > > > > +\tif (nr_swapfiles > 1)\n" @@ -63,7 +63,7 @@ ">> > > > > \n" ">> > > > > How about lazy sorting approach? IOW, if we found prev != p and,\n" ">> > > > > then we can sort it.\n" - ">> > > > Yes.A A That should be better.A A I just don't know whether the added\n" + ">> > > > Yes.\302\240\302\240That should be better.\302\240\302\240I just don't know whether the added\n" ">> > > > complexity is necessary, given the array is short and sort is fast.\n" ">> > > Huh?\n" ">> > > \n" @@ -72,14 +72,14 @@ ">> > > 3. swapoff /dev/XXX2\n" ">> > > 4. use only one swap\n" ">> > > 5. then, always pointless sort.\n" - ">> > Yes.A A In this situation we will do unnecessary sorting.A A What I don't\n" + ">> > Yes.\302\240\302\240In this situation we will do unnecessary sorting.\302\240\302\240What I don't\n" ">> > know is whether the unnecessary sorting will hurt performance in real\n" - ">> > life.A A I can do some measurement.\n" + ">> > life.\302\240\302\240I can do some measurement.\n" ">> I tested the patch with 1 swap device and 1 process to eat memory\n" - ">> (remove the \"if (nr_swapfiles > 1)\" for test).A A \n" + ">> (remove the \"if (nr_swapfiles > 1)\" for test).\302\240\302\240\n" ">\n" "> It is possible that nr_swapfiles > 1 when we have only 1 swapfile due\n" - "> to swapoff. A The nr_swapfiles never decrement on swapoff.\n" + "> to swapoff. \302\240The nr_swapfiles never decrement on swapoff.\n" "> We will need to use another counter in alloc_swap_info and\n" "> swapoff to track the true number of swapfiles in use to have a fast path\n" "> that avoid the search and sort for the 1 swap case.\n" @@ -92,12 +92,6 @@ "Do you think so?\n" "\n" "Best Regards,\n" - "Huang, Ying\n" - "\n" - "--\n" - "To unsubscribe, send a message with 'unsubscribe linux-mm' in\n" - "the body to majordomo@kvack.org. For more info on Linux MM,\n" - "see: http://www.linux-mm.org/ .\n" - "Don't email: <a href=mailto:\"dont@kvack.org\"> email@kvack.org </a>" + Huang, Ying -7d69c18c5c7751762dfe404541a8f6209a5426d5bf284b238306a5fa8b963b50 +b44fdb87fc24e924e009044e1d7a7f00693de58392a62728ada69b70b9a9f4a1
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